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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Audio Measurement and Testing => Topic started by: Christopher Wintz on December 16, 2008, 11:21:27 pm

Title: Measurement Microphones
Post by: Christopher Wintz on December 16, 2008, 11:21:27 pm
Hey Guys,

Kind of an open ended question but I was wondering what people are using for measurment microphones.  Obviously alot of people are using Earthworks M-series, I've seen a few other boutique ones out there.  What do you guys think?

-CW
Title: Re: Measurement Microphones
Post by: Nicolas Lowman on December 16, 2008, 11:45:20 pm
If I am going into an install and tweak a system or create a preset on a dsp for a cabinet, I use the Earthworks M30. The majority of the time the Audix TR40 is sitting in my workbox. I have dropped the M30 before and had to ship it back to the factory for repair. I think it was like a couple hundred bucks to get it fixed. I haven't dropped the Audix yet, and if I do I can replace the whole thing for less than it cost me to fix the Earthworks. I remember hearing say Bob McCarthy he was using the M30 for alignment. I figure if that is good enough for him, it suits me fine. I don't see a B and K in my future that is for sure.

Nicolas
Title: Re: Measurement Microphones
Post by: Ken Freeman on December 16, 2008, 11:55:47 pm
Ditto on the Earthworks M-30.  I have attached a windscreen to mine with velcro so that when I drop it, it bounces.  Still seems to work just fine.  We drop this into a one of the little Lexicon Lamda boxes as it powers from the USB.

Ken
Title: Re: Measurement Microphones
Post by: James Feenstra on December 17, 2008, 12:06:27 am
Ken Freeman wrote on Tue, 16 December 2008 23:55

I have attached a windscreen to mine with velcro so that when I drop it, it bounces

wouldn't that change the frequency response of the mic? I'd hope you take it off before measuring anything
Title: Re: Measurement Microphones
Post by: Josh Evans on December 17, 2008, 03:14:47 am

The only thing I dont like about the M30 is that one has to use a polarity flip when using a Lectrosonics wireless transmitter, and the stupid mic clip. Mic clip can be fixed with a zip tie. The Audix is a great mic, im also using allot of DPA 4090s, and 4007s.

I like the Beyerdynamic, but I havnt found an adaptor for pistonphones.

happy holidays.
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 06:30:51 am
I started with Earthworks, then bought a B&K 4007 (used it for 3 years and then sold it for the same price), picked up a Superlux ECM99 then sold it, bought a cheaper TEF mic (same as Superlux) that I still use as back up and now have a Sound First SF101 with a titanium diaphragm as my primary. I have not dropped this but it appears to be very robust.

www.soundfirst.com

I also have a dual chamber machined metal cigar "canister" (tube) in a leather sleeve (and with threaded end caps) that just fits (diameter and length) standard measurement mic's. This has helped to keep the mic's I have owned in pristine condition.

You can search PSW and google as to the potential problem with plastic diaphragm mic's. Even though my TEF mic is still fine (I baby it), I feel I need to have a more stable/verifiable mic when I travel far to do sound system measurements and especially for "legal" work. Thus the SF101.

Since I also do SPL and noise measurements (legal work, where I could be challenged), I have a B&K 4231 calibrator. So one of the criteria for my mic's is that they are standard diameter at the tip (capsule) so I can calibrate them befor and at the end of each measurement session. Earthworks and others would require an adaptor.
Title: Re: Measurement Microphones
Post by: Ivan Beaver on December 17, 2008, 07:25:36 am
For critical things such as very low freq stuff (Below 30Hz) or loudspeaker parameter measuring I use the M30.  We have a matched pair, and the "other" of the pair sits in the office and never goes out-for use as a reference.

For field type work, such as system alignment I use my "measurement cart" which has 8 stands, 8 rolls of colored cable, Ac power etc that I just wheel in to the venue and spread the mics around.  I use 8 of the older Superlux mics and calibrate them before every use.  

The response of 8 is staying very well "matched" even after about the last 4 years of usage.  The levels are off a tad, but that is why I calibrate them to each other, to make sure the level I am seeing is realative to the others.  My purple mic has the lowest sensitivity, so everything gets padded to it.

I have heard that the new Superlux mics are not as good as the old ones, but cannot confirm nor deny that.
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 07:34:04 am
"I have heard that the new Superlux mics are not as good as the old ones, but cannot confirm nor deny that."

Same here. Ray Rayburn was selling these and he tests each batch as they came in. A year or two ago he he got in a batch and all were way off. So he no longer sells them.
Title: Re: Measurement Microphones
Post by: Jamie Taylor on December 17, 2008, 08:12:21 am
Hi Tom,

I've got a M30, which I bought about two years ago, and it came with a calibration adapter.  Would that work with your B&K calibrator?
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 08:28:32 am
Sorry. I don't know.
Title: Re: Measurement Microphones
Post by: Jens Brewer on December 17, 2008, 11:09:49 am
+1 for the M30, but it does make me nervous carrying that on road, even as well protected as it is.  If you are just starting with measurements, and are primarily using it for system tuning rather than lab work/crossover setting, I would suggest something like the TR40.  Perfectly good for what we need it for and if something bad happens to it (like a lighting guy running over it with a genie lift, ahem), you won't go into seizure.  I know that the good folks at Rational Acoustics are having a X-mas sale on such items right now.   Razz
Title: Re: Measurement Microphones
Post by: Silas Pradetto on December 17, 2008, 11:16:43 am
I use one of those cheapo DBX measurement mics that are sold for use with the Driverack 260. Are these any good? Who makes them?
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 11:45:10 am
I forget the manufacturer's name but these are the same mic as supplied with the Audio Toolbox from Sencore (originally from Terrasonde). I have had a few of these but use my SF101 when doing critical measurements (mostly SPL). 1-2 of my 'expert' sources think these mic's are not very good. But if you can do a "mic compare" procedure against another known "good" mic you may find it is OK.

The problem with all of these cheap plastic diaphragm mic's is that (obviously) they are mass produced and are sold for dirt cheap prices. More conscientious microphone manufacturers will test them (when assembled) and group them according to quality (frequency response, primarily) and then sell the best ones for more money to the buyers who then brand them. When you see the same basic mic (as far as physical appearance) sell for well under $100. (Behringer, for example) versus over $100. (Audix, others) it may be safe to assume that the pricier ones use flatter response diaphragms. But who knows ?

One of the problems with all plastic diaphragms is when they are exposed to higher temeratures (such as storage in a car trunk on a hot summer day), they stretch and then may not return to their previous state when back at cooler temperatures. So the frequency response changes. Even those diaphragms that are (pre) stretched (and possibly heat stretched) by the manufacturer may not be immune to this high-temperature condition. So I wonder how hot the inside of a shipping container gets when exposed to direct sunlight on the container ship from China and/or waiting in either port ?
Title: Re: Measurement Microphones
Post by: Mac Kerr on December 17, 2008, 11:55:24 am
Tom Young wrote on Wed, 17 December 2008 11:45

One of the problems with all plastic diaphragms is when they are exposed to higher temeratures (such as storage in a car trunk on a hot summer day), they stretch and then may not return to their previous state when back at cooler temperatures. So the frequency response changes. Even those diaphragms that are (pre) stretched (and possibly heat stretched) by the manufacturer may not be immune to this high-temperature condition. So I wonder how hot the inside of a shipping container gets when exposed to direct sunlight on the container ship from China and/or waiting in either port ?

I just took the opportunity to check my rather old, well traveled TC30k against a fairly new well cared for M30, and an Audix T40. This was done at about 8' from an L'Acoustics 108. Relative to the M30 my mic had a falling response starting at about 1k that put it down about 2dB at 20k. All the little system response dips tracked perfectly between the two mics. The Audix had a rising response relative to the M30 that put it about 4dB high at 20k, with a sharp rise above about 8k. When I can, I will send my mic in for service, but I am still fairly confident in its performance. I pack it in a plastic tube with foam ends, then in my tool bag, which goes in my suitcase, which goes in the belly of the plane many times a year. So far so good.

Mac
Title: Re: Measurement Microphones
Post by: Ian M Barfoot on December 17, 2008, 11:59:58 am
I to have an M30 which seems to be very good, not sure I would say they were too expensive for the road unless I have a slightly higher tolerance to cost. I have a number of DPA 4090's which could be used though I like those on Timpani or percussion so not always available. If it is critical I assume that Bruel & Kjar (Parents of DPA I believe) still make exceptional measurement microphones?
Title: Re: Measurement Microphones
Post by: Art Welter on December 17, 2008, 01:41:00 pm
Tom,

Last winter, after getting lousy results from some subs I was building, used one of my B & K 4004 mics (+/- 2dB 10HZ to 40KHZ) in place of the mic as supplied with the Audio Toolbox  from Terrasonde.

This is how far off I found it to be:

-10 at 20HZ, -9 at 25, -8 at 30, -6 at 40, OK at 45 & 50, -3 at 55, -2 at 60, -1 at 70.

Turned out the sub's response was fine, but the mic was not.

The Terrasonde mic also read +2dB at 200 and 250, which was as far up as I was testing, but made the subs response look even more anemic, a full 12 dB loss over a decade of frequency!

The mic that came with a DOD RTA (the RTA & mic costing only about $250) that I have had for about ten years was within a few dB of flat in the same range- go figure.

Like you and Ivan say, best to compare your test mics frequently to a known quantity.

Art Welter
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 02:55:44 pm
"If it is critical I assume that Bruel & Kjar (Parents of DPA I believe) still make exceptional measurement microphones?"

Hmmmm. Perhaps. And this partly depends on your definition of "critical".

Bruel and Kjaer 4007 (and other members of the 4000 family) are all very good and maintain their quality very well. I am not sure how robust they are. I have used a few SIM systems that had damaged 4007's but I don't know what they went through to get trashed like that. When I owned a 4007 I treated it very well because of its cost and my need for certainty. B&K introduced a cheaper model perhaps 2 years ago that is in the $700-800.00 range. I have not used these and don't know how they compare including how robust they may be.

Other measurement mic's used by acousticans and the like are available from ACO Pacific, GRAS and perhasp 1-2 others. I don't know how these compare to B&K's offerings.

I am very confident in my SF101 (enough to use it in *my* critical work) and will be able to tell in a few years if it remains 'good' as long as we would expect from a B&K.

Sorry if this is a bit vague. I guess that a simpler answer could have been that if you show up with a B&K 4007 many folks will take you very seriously.
Title: Re: Measurement Microphones
Post by: Tom Young on December 17, 2008, 04:13:00 pm
Yikes.

Guess I'll wait a few weeks and then put my ATB mic up for sale Wink

Not really surprised, though.

Thanks !
Title: Re: Measurement Microphones
Post by: Bennett Prescott on December 17, 2008, 05:59:17 pm
Ray Rayburn's site for measurement microphones is http://testmic.com/.

I have an ECM-999 from when they were good (he doesn't sell them anymore, due to aforementioned quality control issues) for my "beat it up, I don't care mic".
My "serious measurement" mic is one of his SF-101s, which has been really excellent. I haven't ever tried to measure in a snowstorm with it, but supposedly it'll do that... all I know is the thing is flatter than +/- 1dB for the entire reasonable measurement range (I don't need to measure below 20Hz or above 18kHz).

I see he now offers the SF-111, which is even better for less than twice the money!
Title: Re: Measurement Microphones
Post by: Art Welter on December 17, 2008, 07:30:35 pm
Since I only have, and only tested one of these mics, I would not want to say they all are that bad, but I bet they are not particularly consistent unit to unit..
Title: Re: Measurement Microphones
Post by: Christopher Wintz on December 17, 2008, 07:37:17 pm
Art Welter wrote on Wed, 17 December 2008 18:30

Since I only have, and only tested one of these mics, I would not want to say they all are that bad, but I bet they are not particularly consistent unit to unit..


which is why you pay more for a matched pair.

Interesting input guys.  I'm getting myself a little holiday gift and building out my SMAART work station.  I have the software and computer and am getting a Presonus USB preamp, I'll probably barrow a TC-30 from work until I save enough for as decent measurment mic.  

Do you guys find yourself needing a matched pair very often?  I thought about holding off until I could afford a matched pair of M30's, but I can't think of a test situation where the only thing that affords you is the luxary of not getting up and moving the test point yourself.

Thanks for the input though guys, very cool reading here.

Edit:  What do you guys think about the Lectroacoustics wireless test system?  It seems kinda gimmicy to me.  Does putting a wireless device in the single path really change the frequancy response THAT much?  I mean I know it's going to add a little color, but really?  Is there a dynamic issue at play that I've never heard of (compression during a-d/d-a convertsion...?...)?
Title: Re: Measurement Microphones
Post by: Steve Devino on December 17, 2008, 11:37:39 pm
FYI, the TC-30 ad M30 are identical mics other than the color of the case. Eric Blackmer once told me, it seems people need "measurement" in the model to make it real (paraphrasing).

If you do any recording the an M30 or tc30 or QTC30 pair is one of the absolute best recording mics for acoustic guitar, live choir, small orchestras, or drum overheads.

Steve
Title: Re: Measurement Microphones
Post by: Arthur Skudra on December 18, 2008, 01:15:01 am
Christopher Wintz wrote on Wed, 17 December 2008 19:37

Edit:  What do you guys think about the Lectroacoustics wireless test system?  It seems kinda gimmicy to me.  Does putting a wireless device in the single path really change the frequancy response THAT much?  I mean I know it's going to add a little color, but really?  Is there a dynamic issue at play that I've never heard of (compression during a-d/d-a convertsion...?...)?
Nothing gimmicky about the Lectrosonics TM400 set.  Being a digital hybrid wireless, they have eliminated the need for the companding circuits used in typical wireless systems.  Companding circuits would make your measurement non-linear.  EV & HME used to make test and measurement wireless systems that bypassed the companding circuit, unfortunately the demand for such systems is very low, and were discontinued.  AFAIK, the Lectrosonics TM400 is the only wireless currently available that is suitable for test and measurement.

In addition to a flat frequency response, linearity of the measurement signal is very important for making accurate measurements of sound systems using software such as Smaart.  As a side benefit, the Lectrosonics wireless is flat down to 40 Hz, most other wireless systems don't go that low.

If you do many large venues, the TM400 can prove to be invaluable!
Title: Re: Measurement Microphones
Post by: Geri O'Neil on December 18, 2008, 06:59:13 am
Arthur Skudra wrote on Thu, 18 December 2008 00:15

Christopher Wintz wrote on Wed, 17 December 2008 19:37

Edit:  What do you guys think about the Lectroacoustics wireless test system?  It seems kinda gimmicy to me.  Does putting a wireless device in the single path really change the frequancy response THAT much?  I mean I know it's going to add a little color, but really?  Is there a dynamic issue at play that I've never heard of (compression during a-d/d-a convertsion...?...)?
Nothing gimmicky about the Lectrosonics TM400 set.  Being a digital hybrid wireless, they have eliminated the need for the companding circuits used in typical wireless systems.  Companding circuits would make your measurement non-linear.  EV & HME used to make test and measurement wireless systems that bypassed the companding circuit, unfortunately the demand for such systems is very low, and were discontinued.  AFAIK, the Lectrosonics TM400 is the only wireless currently available that is suitable for test and measurement.

In addition to a flat frequency response, linearity of the measurement signal is very important for making accurate measurements of sound systems using software such as Smaart.  As a side benefit, the Lectrosonics wireless is flat down to 40 Hz, most other wireless systems don't go that low.

If you do many large venues, the TM400 can prove to be invaluable!


Amen. Absolutely some of the best money I've ever spent. That and a tablet!

Geri O
Title: Re: Measurement Microphones
Post by: John Roberts {JR} on December 18, 2008, 09:47:19 am
Arthur Skudra wrote on Thu, 18 December 2008 00:15

Christopher Wintz wrote on Wed, 17 December 2008 19:37

Edit:  What do you guys think about the Lectroacoustics wireless test system?  It seems kinda gimmicy to me.  Does putting a wireless device in the single path really change the frequancy response THAT much?  I mean I know it's going to add a little color, but really?  Is there a dynamic issue at play that I've never heard of (compression during a-d/d-a convertsion...?...)?
Nothing gimmicky about the Lectrosonics TM400 set.  Being a digital hybrid wireless, they have eliminated the need for the companding circuits used in typical wireless systems.  Companding circuits would make your measurement non-linear.  EV & HME used to make test and measurement wireless systems that bypassed the companding circuit, unfortunately the demand for such systems is very low, and were discontinued.  AFAIK, the Lectrosonics TM400 is the only wireless currently available that is suitable for test and measurement.

In addition to a flat frequency response, linearity of the measurement signal is very important for making accurate measurements of sound systems using software such as Smaart.  As a side benefit, the Lectrosonics wireless is flat down to 40 Hz, most other wireless systems don't go that low.

If you do many large venues, the TM400 can prove to be invaluable!


Putting a 2:1 compander in your audio path doubles the frequency response errors of that path between the compressor and the expander.

The compressor at the mic squashed the signal 2:1, at the receiver it gets expanded back out 1:2. Any errors in that wireless link get expanded too.

So if that path is a little sloppy, it becomes more sloppy.  The -3db point now becomes a - 6dB point. Note: if the path has known problems the compander can be designed to be less sensitive to certain frequency regions but I doubt many (any?) go to that much trouble.  

JR


Title: Re: Measurement Microphones
Post by: Christopher Wintz on December 18, 2008, 10:52:28 am
That makes alot more sense now.  I was kinda wondering what was up.  I have heard of using companding before as a means of reducing single noise in comms lines, but I didn't realize that wireless units alos compand, thanks guys.
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on December 18, 2008, 11:57:25 am
They have a new mic clip now.
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on December 18, 2008, 12:06:34 pm
It's a 1/2" to 1/4" adapter with an O ring on the 1/4" side.  Seems like it would work since the seal is maintained.
Title: Re: Measurement Microphones
Post by: Mesadude on December 18, 2008, 12:47:50 pm
anyone who ever worked with Josephson C-550?
They claim it's the most accurate measurement microphone ever made..

I love the other Josephson's i've tried so far, but never got to use the C-550.

http://www.josephson.com/c550.html

Thanks.

Willem
Title: Re: Measurement Microphones
Post by: Jake Hogberg on December 18, 2008, 04:31:33 pm
Shocking...my 50$ behringer mic has the same frequency response as both of my 600$ m30's, although I can't speak for the phase. Can't argue with that. Plus, having the best measurement mic (which might not be any better) WILL NOT matter unless you have the best signal path, and even more importantly, a complete understanding of making acoustic measurements and interpreting them. Just my opinion.
Title: Re: Measurement Microphones
Post by: Iain_Macdonald on December 18, 2008, 04:48:21 pm
Hi,

Just in case some of you might have missed it. Earthworks have a M23. This appears to have a much better price than the M30.

Iain.
Title: Re: Measurement Microphones
Post by: Tom Young on December 18, 2008, 05:22:55 pm
I failed to mention Josephson as one of the leaders in high-quality measurement mic's. They make some very good mic's.

But I am not aware that they are considered to surpass Bruel and Kjaer, who have earned (as far as I'm concerned) their reputation, with many of their acoustic test equipment devices, as the leader.
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on December 18, 2008, 09:34:05 pm
The M23 is similar to the Smaart M30 which was an OEM version for SIA.  Rational Acoustics carries something similar, perhaps it's the M23, I don't recall.
Title: Re: Measurement Microphones
Post by: Mac Kerr on December 22, 2008, 02:28:45 pm
Mac Kerr wrote on Wed, 17 December 2008 11:55

I just took the opportunity to check my rather old, well traveled TC30k against a fairly new well cared for M30, and an Audix T40. This was done at about 8' from an L'Acoustics 108. Relative to the M30 my mic had a falling response starting at about 1k that put it down about 2dB at 20k. All the little system response dips tracked perfectly between the two mics. The Audix had a rising response relative to the M30 that put it about 4dB high at 20k, with a sharp rise above about 8k. When I can, I will send my mic in for service, but I am still fairly confident in its performance. I pack it in a plastic tube with foam ends, then in my tool bag, which goes in my suitcase, which goes in the belly of the plane many times a year. So far so good.

Mac

Here is a screen shot of the 3 traces. The magenta trace is the well cared for M30, the green trace is the Audix TR40, and the dark blue trace is my well traveled TC30k. Considering the time my mic has spent in airline baggage transport or in the trunk of my car, I am pleased with its performance. When I get a chance it will go back to Earthworks for a tuneup.

This is the untouched output of an L'Acoustics 108P. The delay shown in the screen shot is irrelevant it is not from the traces I saved.

Mac

index.php/fa/19788/0/
Title: Re: Measurement Microphones
Post by: Jeff Babcock on December 22, 2008, 02:48:54 pm
Yikes, the TR40 is around 6db hotter in the 5-7K range.  I'm surprised the difference is that significant.  Makes me really think twice about trusting a single mic, perhaps I should own a couple different ones and compare their results for more critical measurement applications.

Title: Re: Measurement Microphones
Post by: Adam Robinson on December 22, 2008, 02:53:39 pm
I own a TR40 and when I tested it against others, I did not have the same result.

Title: Re: Measurement Microphones
Post by: Art Welter on December 22, 2008, 03:08:31 pm
Jeff,

Look again, the deviation is more like 2 or 3dB up high, the blue trace is down in level throughout the graph.

Not that 3 dB, a doubling of power is insignificant..

The problem is which mic is correct, the magenta and blue trace are more similar in the HF, so the green may be the one that is too “hot” on top.
Title: Re: Measurement Microphones
Post by: Art Welter on December 22, 2008, 03:11:21 pm
Adam,

The different results you got are why individual tests are so important against a known benchmark.

Title: Matching Microphones, or not...
Post by: Mac Kerr on December 22, 2008, 03:19:09 pm
Adam Robinson wrote on Mon, 22 December 2008 14:53

I own a TR40 and when I tested it against others, I did not have the same result.


Against what others? All mics will vary slightly, even 2 brand new mics of the same type. I did this test because I found that with 3 different speaker systems, dv-DOSC mains, VRX932 delays, and 108P front fills I was making very similar eq changes. I asked for the other mics to check to see if there was an issue with my measurement mic. While it is down in level it is not grossly different from the other Earthworks, so I remain fairly confident in its output. As I said, I will still get it checked at the factory, but I don't feel the differences in the 2 mics greatly effected the alignment of my system. Final tweaking was done by walking and listening to the transitions between zones and the overall coverage of the room.

Mac
Title: Re: Measurement Microphones
Post by: Jeff Babcock on December 22, 2008, 03:41:12 pm
I realize the Audix is generally hotter in the traces which accounts for some of the difference - numbers aside there is enough difference in the Audix response vs the other mics that it would likely influence me, that's all I am saying.  Obviously ears should be the final judge but that might lead me astray.
Title: Re: Measurement Microphones
Post by: Bob McCarthy on December 22, 2008, 04:26:44 pm
I own 8 Earthwoks M30s. They are sufficient for my needs, although I probably would have bought DPA 4090 series mics had they been on the market at the time I bought mine. They are now 5 years old. 2 of them will go back for rework shortly. They drift in level over time and as a result I calibrate them at every job. I never do any work with a single mic so for me relative level and freq response are more critical parameters than absolute freq response.

As for the earlier question re the B&K calibrator - it SHOULD work with the M30 adaptor. Calibrators are made to a standard and different mics have a specific adaptor mechanism to fit that.

Finally, at a recent SIM school in Germany a guy pulled out his Beringer mic and we compared it to the DPA 4007 using a dual mic transfer function. Everyone was prepared for a big laugh but the 25 cent mic did very well (this is the second time I have seen this so I was not too shocked.) So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose.
Title: Re: Measurement Microphones
Post by: Helge A. Bentsen on December 22, 2008, 09:06:43 pm
Slightly off topic:

Never tried to measure anything with a M30, but I've used it a couple of times on snare bottom, it's one of the best microphones I've used for that application  Smile  
Title: Re: Measurement Microphones
Post by: Tom Young on December 23, 2008, 07:35:30 am
"So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose."

I actually tried their measurement mic. If you ignore the phase response that results from the 4 front-aimed capsules and the one rear-aimed capsule.... they are not that bad. But make sure you use their preamp or the frequency response will be restricted to 160Hz-7kHz.

 Twisted Evil  
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on December 23, 2008, 05:54:26 pm
Tom Young wrote on Tue, 23 December 2008 06:35

"So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose."

I actually tried their measurement mic. If you ignore the phase response that results from the 4 front-aimed capsules and the one rear-aimed capsule.... they are not that bad. But make sure you use their preamp or the frequency response will be restricted to 160Hz-7kHz.

 Twisted Evil  



It's a good thing I don't drink coffee!
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on December 23, 2008, 06:01:00 pm
Bob McCarthy wrote on Mon, 22 December 2008 15:26

I own 8 Earthwoks M30s. They are sufficient for my needs, although I probably would have bought DPA 4090 series mics had they been on the market at the time I bought mine. They are now 5 years old. 2 of them will go back for rework shortly. They drift in level over time and as a result I calibrate them at every job. I never do any work with a single mic so for me relative level and freq response are more critical parameters than absolute freq response.

As for the earlier question re the B&K calibrator - it SHOULD work with the M30 adaptor. Calibrators are made to a standard and different mics have a specific adaptor mechanism to fit that.

Finally, at a recent SIM school in Germany a guy pulled out his Beringer mic and we compared it to the DPA 4007 using a dual mic transfer function. Everyone was prepared for a big laugh but the 25 cent mic did very well (this is the second time I have seen this so I was not too shocked.) So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose.


I have measured six of these against the seventh and they were all within half a dB.  They were purchased as a set of 8 for a SIM3 rig and Earthworks did a very nice job matching the frequency response.

 http://a908.ac-images.myspacecdn.com/images01/95/l_eb18244c0 a75a9834862127df64db503.jpg

I have found the Behringer mic to be acceptable for anyone using a single mic and doesn't mind the potential ridicule they might get (not from me).  I intend to get a matched set of 6 M30s, when the money is there.  I am also interested in the Beyer mic ($200).  The one I measured was perfectly matched to the M30s in the room, but I've heard they have other issues.  Any thoughts?
Title: Re: One Measurement Microphone
Post by: Mac Kerr on December 23, 2008, 06:06:21 pm
I only use 1 mic, and I spend a lot of time moving it around the room. I am happy to report my mic is perfectly matched to itself!   Laughing

Mac
Title: Re: One Measurement Microphone
Post by: Klaus {nojunk} Zimmermann on December 23, 2008, 06:55:12 pm
quick question:
any1 used a kt 6051 (from dn6k system)?  nny idea who's the original manufacturer?
tx
Title: Re: One Measurement Microphone
Post by: Josh Evans on December 24, 2008, 09:31:27 am
We could talk about this until the cows come home.

Currently I have two DPA 4090 and love them!!! Im also using two tm400 wireless units, and don't have to do the stupid ridiculous polarity flip like the M30. Im also using three small fold able stands. One I have had for a couple of years ago it was a custom job. Two of them are from Rational Acoustics, and I have another clamped to my table so that four mics.

Yes Harry the M30 has a new mic clip, but the DPA mic clip puts it to shame.  

I would buy a 4007 as long as its not my dime. Ray has some great mics, and should not be overlooked.

http://www.rationalacoustics.com/store/mic-stands-clamps

http://www.rationalacoustics.com/store/microphones
I have two of the mic cases as well.

In the picture I attached you can see the two mic stands in the case lid, and also a pouch holding the left over pieces from about 4 other measurement mics. Including an m30 that got ran over by a really big truck.... doh!

I guess measurement mics are allot like a contraceptive . They all do the same thing, and in a pinch anyone will do, but in the long run we all have our preference.

happy holidays from Dubai!

Josh
Title: Re: Measurement Microphones
Post by: Kent Clasen on December 24, 2008, 10:14:06 am
While I haven't compared mics myself, I use the Audix TR40 and have a handful of the Superlux for multi mic measurement, where I am mostly looking at relative changes in different areas.

An interesting note, I don't know if it was already discussed, I didn't read every post. Pat Brown compared measurement mics in his VOL36 Aug 08 newsletter.  He found the angle of incidence to have a major impact on the mics.  He lists several mics and the recommended angle.

He found a 10dB frequency response deviation using the same angle on every mic, but when using the proper incidence angle, only 2dB diff!

Some angles where 0, 45, and 90 degrees depending on which microphone you are using. DPA, Earthworks, Soundfirst were some he tested.
Title: Re: One Measurement Microphone
Post by: Bob McCarthy on December 24, 2008, 11:04:25 am
Josh Evans said ---
"I guess measurement mics are allot like a contraceptive . They all do the same thing, and in a pinch anyone will do, but in the long run we all have our preference."

Thanks Josh for for linking up two of my favorite subjects (acoustic measurement taking 2nd place here.)

Happy Holidaze to you

6o6
Title: Re: Measurement Microphones
Post by: Dave Barnett on December 24, 2008, 11:40:59 am
Tom Young wrote on Tue, 23 December 2008 06:35

"So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose."

I actually tried their measurement mic. If you ignore the phase response that results from the 4 front-aimed capsules and the one rear-aimed capsule.... they are not that bad. But make sure you use their preamp or the frequency response will be restricted to 160Hz-7kHz.

 Twisted Evil  


Now that's comedy.
Title: Re: Measurement Microphones
Post by: Dave Barnett on December 24, 2008, 11:49:55 am
Kent Clasen wrote on Wed, 24 December 2008 09:14

While I haven't compared mics myself, I use the Audix TR40 and have a handful of the Superlux for multi mic measurement, where I am mostly looking at relative changes in different areas.

An interesting note, I don't know if it was already discussed, I didn't read every post. Pat Brown compared measurement mics in his VOL36 Aug 08 newsletter.  He found the angle of incidence to have a major impact on the mics.  He lists several mics and the recommended angle.

He found a 10dB frequency response deviation using the same angle on every mic, but when using the proper incidence angle, only 2dB diff!

Some angles where 0, 45, and 90 degrees depending on which microphone you are using. DPA, Earthworks, Soundfirst were some he tested.


I guess they're not truly omnidirectional then?
Title: Re: Measurement Microphones
Post by: Too Tall (Curtis H. List) on December 24, 2008, 01:15:55 pm
Bob McCarthy wrote on Mon, 22 December 2008 16:26

I own 8 Earthwoks M30s. They are sufficient for my needs, although I probably would have bought DPA 4090 series mics had they been on the market at the time I bought mine. They are now 5 years old. 2 of them will go back for rework shortly. They drift in level over time and as a result I calibrate them at every job. I never do any work with a single mic so for me relative level and freq response are more critical parameters than absolute freq response.

As for the earlier question re the B&K calibrator - it SHOULD work with the M30 adaptor. Calibrators are made to a standard and different mics have a specific adaptor mechanism to fit that.

Finally, at a recent SIM school in Germany a guy pulled out his Beringer mic and we compared it to the DPA 4007 using a dual mic transfer function. Everyone was prepared for a big laugh but the 25 cent mic did very well (this is the second time I have seen this so I was not too shocked.) So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose.


A point of interest on the Behringer.

I use a 2-conductor unbalanced microphone made by Kim Giardin.
It works with the built in mic preamp in the Praxis Audpod (Interface).

The mic is a 9/32" tube with the capsule in one end.

index.php/fa/19839/0/

NOTE: On the other end of the pipe is a female RCA. Kim makes a 9/32" brass tube that is about 36" long as an extension. With the 11" mic reaches almost 4 feet to get away from mic stand reflections)

The mic cable can be no more then 30' and 25' is better or the top end rolls off.

The mic is calibrated for both freqency SPL and phase to a Top line ACO mic for hundreds of points and can be imported into several programs, including Praxis.

I asked Kim to come up with a way to make his mic balanced low impedance so I could use it over long distances.

Rather then buy the transformer/electronics or other pieces he suggested that gutting a Behringer to use everything except the capsule would be the cheapest for parts and labor.

When he started working on it he found that there is an active EQ filter built into its circuit board.

He made it work anyway (including calibration), but decided he would NEVER do that again.

Long story short, do we know of any other microphones that do this?
Title: Re: Measurement Microphones
Post by: Tom Young on December 24, 2008, 10:46:59 pm
"I guess they're not truly omnidirectional then"

Absolutely not. No mic is.

How does a mic remain omnidirectional when the mic (diaphragm) is turned to the point that direct sound does not strike it or even move it at higher frequencies where diffraction cannot occur ?

But the better designed and more expensive mic's have more even off-axis response, which is very audible in listening (when you use them for recording or sound reinforcement) and obviously has an effect when used for measurements.

If microphones (any and all) were measured and the data was provided to us at/with the level of detail that most professional loudspeakers are ..... I think we'd all be a bit surprised and possibly dismayed.
Title: Dinner conversation
Post by: Mac Kerr on December 24, 2008, 10:56:25 pm
Tom Young wrote on Wed, 24 December 2008 22:46

"I guess they're not truly omnidirectional then"

Absolutely not. No mic is.

How does a mic remain omnidirectional when the mic (diaphragm) is turned to the point that direct sound does not strike it or even move it at higher frequencies where diffraction cannot occur ?

But the better designed and more expensive mic's have more even off-axis response, which is very audible in listening (when you use them for recording or sound reinforcement) and obviously has an effect when used for measurements.

If microphones (any and all) were measured and the data was provided to us at/with the level of detail that most professional loudspeakers are ..... I think we'd all be a bit surprised and possibly dismayed.

Hmmm... Tom, didn't we just have this conversation at dinner the other night? It's interesting that your point about balloon plots for mics came up here so soon.

Mac
Title: Re: Dinner conversation
Post by: Tom Young on December 25, 2008, 07:55:58 am
What can I say ?

It was fortuitous that this subject came up befor I forgot this aspect of the subject  Wink

Time for some eggnog for breakfast........

Title: Re: Matching Microphones, or not...
Post by: Adam Robinson on December 25, 2008, 01:43:38 pm
Mac Kerr wrote on Mon, 22 December 2008 14:19

Adam Robinson wrote on Mon, 22 December 2008 14:53

I own a TR40 and when I tested it against others, I did not have the same result.


Against what others? All mics will vary slightly, even 2 brand new mics of the same type. I did this test because I found that with 3 different speaker systems, dv-DOSC mains, VRX932 delays, and 108P front fills I was making very similar eq changes. I asked for the other mics to check to see if there was an issue with my measurement mic. While it is down in level it is not grossly different from the other Earthworks, so I remain fairly confident in its output. As I said, I will still get it checked at the factory, but I don't feel the differences in the 2 mics greatly effected the alignment of my system. Final tweaking was done by walking and listening to the transitions between zones and the overall coverage of the room.

Mac


Sorry for being late on the response.  I meant in my reply above that when I tested my TR40, I found it to not have that 6db (avg) boost against other mics in my test,  like your picture showed.  All of the responses were decently close to each other.

FWIW, a while back, I did have one go wonky on me.  I sent it back to Audix and they were happy to repair it.  
Title: Re: Measurement Microphones
Post by: Brad Weber on December 30, 2008, 09:24:45 am
Bennett Prescott wrote on Wed, 17 December 2008 17:59

I see he now offers the SF-111, which is even better for less than twice the money!

Just got a SF111 from Ray a couple of weeks ago along with an "unlocked" SP395 for field survey use.  The SF111 will now be the reference for the Earthworks M30S mics I usually use on site.
Title: Re: Measurement Microphones
Post by: Tom Young on December 30, 2008, 10:58:49 am
Me, too.

I already had a SF101 and recently bought the SP395 from Ray.

Please let me know what you find it takes to get your SP395 to talk to your PC (Terralink).
Title: Re: Measurement Microphones
Post by: Christopher Wintz on January 01, 2009, 06:29:01 pm
Not to beat a dead horse, but I have more questions about measurement mics.

I picked up a Beyerdynamic MM1 the other day.  Not the greatest mic on the market, but it was well within my price range and it looks like it will be a good performer.

In the spec booklet it mentions an energy build up that can accour in front of the mic at 10+KHz, if the make is facing directly towards the source, thus throwing off the frequancy response and creating some phase issues.  Which makes sense as the wavelangth would then be smaller then the diameter of the mic.

Two questions:
Are all mics susceptible to this? (And that all measurement mics should be perpendicular to the source during measurement...)
How would you compensate for this while using a mic calibrator, do you need to?
Title: Calibration
Post by: Mac Kerr on January 01, 2009, 06:34:11 pm
Christopher Wintz wrote on Thu, 01 January 2009 18:29

How would you compensate for this while using a mic calibrator, do you need to?

A mic calibrator is used to set a known reference level in your measurement system. It has nothing to do with frequency response, it creates a calibrated level at 1kHz. Using that known level you can adjust your meter or analyzer to match that level while the calibrator is on.

Mac
Title: Re: Measurement Microphones
Post by: Tom Young on January 01, 2009, 07:24:15 pm
Yes, all microphones behave in this manner. Higher frequencies cannot bend (diffract) around the mic head and be picked up by the mic, as lower frequencies do. That being said, more expensive mic's (and especially in the measurement mic category) are designed to be flatter off axis (as well as on axis), than cheaper microphones can be. There is one exception (to this directional characteristic at high frequencies tendency) that I can think of: the diffusion sphere that Bruel and Kjaer makes for their omni-directional mic's to make them more omni-directional at very high frequencies. Look it up.

This has no bearing on calibration, which in this context is setting the microphone gain so that the SLM sensitivity results in accurate, *absolute* SPL measurements. Calibration is done most often at 1kHz (well below where the mic begins to become directional) and the driver in the calibrator faces directly into the mic diaphragm. FYI- the other "standard" calibration frequency is 250Hz. But 1kHz is significant/important because whether the SLM is in the Flat or A or C weighting position.... they are all flat (unweighted) at 1kHz.

Beyer Dynamic is basically referencing the difference between free field measurement and diffuse feild measurement.

If you google on those terms and read up on what you find, you will grasp more how this comes into play.

(edited for grammar, spelling and additional trivial calibration factoids)
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on January 01, 2009, 10:46:41 pm
Christopher Wintz wrote on Thu, 01 January 2009 17:29

Not to beat a dead horse, but I have more questions about measurement mics.

I picked up a Beyerdynamic MM1 the other day.  Not the greatest mic on the market, but it was well within my price range and it looks like it will be a good performer.

In the spec booklet it mentions an energy build up that can accour in front of the mic at 10+KHz, if the make is facing directly towards the source, thus throwing off the frequancy response and creating some phase issues.  Which makes sense as the wavelangth would then be smaller then the diameter of the mic.

Two questions:
Are all mics susceptible to this? (And that all measurement mics should be perpendicular to the source during measurement...)
How would you compensate for this while using a mic calibrator, do you need to?


You should probably just go ahead and face the mic toward the source.  Good luck finding a calibrator adapter to fit that mic.  If I remember right it's not a standard size.  Perhaps Beyer makes an adapter.  I measured one of these against an M30 a few months ago and it measured quite well.  I have heard they are not all like that so you may be one of the lucky ones.
Title: Re: Measurement Microphones
Post by: Arthur Skudra on January 02, 2009, 12:48:39 pm
Ray Rayburn scanned in a bunch of pages from an old Gen Rad manual on measurement microphones, the principles are the same regardless of the age of this material, but it would be a good read particularly about the grazing effects of microphones vs. their diameter (see "Microphones Pages 1-17").
http://www.soundfirst.com/GenRad.html

Pat Brown did an article recently (Vol 36 August 2008) comparing the response of several different measurement microphones at different angles, maybe this is a good time to become a member so you can download it from their server, and benefit from other stuff that will increase your knowledge of professional audio.  He found that the Earthworks M30 has the flattest response at 90 degrees!  Interesting stuff!
Title: Re: Measurement Microphones
Post by: Jens Brewer on January 03, 2009, 02:20:32 am
Arthur Skudra wrote on Fri, 02 January 2009 12:48

Pat Brown did an article recently (Vol 36 August 2008) comparing the response of several different measurement microphones at different angles....He found that the Earthworks M30 has the flattest response at 90 degrees!


I asked him about his methodology for that test and his choice of the 4090 as the reference.  If you look at the extremely similar deviations of the other mics in fig. 2, it leads me to believe that 4090 was the one with the predominate anomolies.

I also mentioned that EarthWorks recommends that the capsule be aimed at the source, not 90 degrees.  In fact, out of the 8 mics he tested, he determined that only 3 should be used on axis.   Rolling Eyes   I think if Pat had chosen another mic as his reference for the angle incident test, the results would have been a whole lot different.  Ultimately, for what we're using these tools for, I'd say that having a good SOP is a lot more important than worrying about your angle of incidence.  I plan to keep aiming the M30 at the target even if my 15-20kHz area gets skewed a dB or two.

+1 on joining SAC though.....the library is an excellent resource, Pat is a great teacher, and the mailing list has some deep talent.
Title: Re: Measurement Microphones
Post by: Arthur Skudra on January 03, 2009, 12:06:09 pm
Interesting you mention this Jens.  I wish Pat went into further depth with this particular article, because it seems to open up a lot of questions about methodology that are worth exploring.  Also the consistency of the data is important too, mic to mic within the same model!  How does he know the reference mic he used is correct?  And for the record, I find aiming the M30 to the source to be the optimal configuration for me, though honestly I need to spend more time digging into this further for myself.

Which begs a controversial question:

If we are willing to accept cheaper measurement microphones for live sound reinforcement optimization that may deviate in response above say 10 kHz as an acceptable alternative to the more expensive ones (that are ruler flat smooth up to 20, 30, or even 40 kHz), does measurement angle (of which deviates the most above 10 kHz) really matter that much?  How often do you find yourself tweaking a sound reinforcement system above 10 kHz?  To further clarify the context of what were doing, we're dealing with a live sound reinforcement system in a mid to large sized room, not a testing lab or recording studio.
Title: Re: Measurement Microphones
Post by: Irving Albert Hammond Jr. on January 08, 2009, 04:25:10 pm
Has anybody compared the older tr-40 to the newer tr-40a.
I'm wondering why the change if the spec sheets are identical.

Just got a new tr-40a and its aesthetically different than the older tr40's.

This new one has a flat finish and the top grill part looks different and i bought this from a reputable company so i doubt its a fake

Its also missing the omnidirectional sign at the top.
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 08, 2009, 04:54:03 pm
I was recently given a Peavey ERO 10 that certainly appears to be a measurement mic it's still in the original flighcase style box with the Peavey Architectural Acoustics logo on it.  Does anyone know anything about these?

Thanks

Charlie
Title: Re: Measurement Microphones
Post by: Tom Young on January 08, 2009, 07:03:23 pm
I read a post somewhere (a few years ago), from someone who knew what they were talking about, that categorized this mic as "pretty dang good".

I suggest that you find an opportunity to do a comparison against a known quantity and see how it looks. You need to look at both frequency (amplitude) and phase response.
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 08, 2009, 07:38:47 pm
Thanks for that Tom,

So one for the "keep pile" then.

It does look pretty well made and I guess finding out more will give me something to do while I'm on "light duties" waiting to get this damn hernia fixed.

Charlie
Title: Re: Measurement Microphones
Post by: Tom Young on January 08, 2009, 07:44:09 pm
Ouch. Hope you heal OK.

You might be able to find a spec sheet for this mic archived at Peavy's website.

It has a diamond-sputtered diaphragm, if I recall correctly. This *may* make it superior to the run-of-the-mill plastic diaphragm capsules.
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 08, 2009, 07:52:45 pm
Thanks for the good wishes Tom,

Sounds as if it's probably worth using over the TR40 for the moment until I buy another M30 to replace the one that got destroyed by some idiot dropping my bag over a balcony rather than walking it down a few steps.

Charlie
Title: Re: Measurement Microphones
Post by: Art Welter on January 08, 2009, 08:13:31 pm
Tom,

“It has a diamond-sputtered diaphragm”

Do you mean gold sputtered, or did Hartley come up with a more expensive process? ;^)

Art
Title: Re: Measurement Microphones
Post by: Jens Brewer on January 09, 2009, 03:12:48 am
Arthur Skudra wrote on Sat, 03 January 2009 12:06

If we are willing to accept cheaper measurement microphones for live sound reinforcement optimization that may deviate in response above say 10 kHz as an acceptable alternative to the more expensive ones (that are ruler flat smooth up to 20, 30, or even 40 kHz), does measurement angle (of which deviates the most above 10 kHz) really matter that much?


While important, I don't think measurement angle is as important as a good measurement game plan well executed.  And don't forget that frequency measurement is only part of what we use measurement mics for in the field (delay setting, level setting, aiming and coverage).  That in mind, the low and mid level mics can be perfectly acceptable, and in some environments may be preferable.

Quote:

How often do you find yourself tweaking a sound reinforcement system above 10 kHz?


Sometimes a mild high shelf boost is appropriate, but that is just as much a matter of listening as it is measuring.  (Although it's nice when your measurements back up what you're hearing.)

-------------

Flipping the question:  How important is mic accuracy in the very lowest 2 octaves (20-80Hz) in relation to EQing subs?  How often are you guys making more than one frequency correction (if that) in the sub bandpass?  I find that with well behaved, properly crossed and aligned systems, level setting of the subs is usually all that's needed (and any extra 'flava', if desired, can be done by ear.)
Title: Re: Measurement Microphones
Post by: Tom Young on January 09, 2009, 06:06:43 am
I was right about the diamond part but not the "sputtered" part and this may, or may not, apply to the "ERO-10" mic that Charlie has.

See:

http://www.peavey.com/assets/literature/manuals/80302370.pdf

Again: I recall that Peavey had a measurement mic with this diaphragm material. But I have no idea what model it was.
Title: Re: Measurement Microphones
Post by: Tom Young on January 09, 2009, 06:53:17 am
Low frequency measurements are considered by both sound system folks and acousticians to be difficult and questionable unless you use a special device (mic). I *think* the questionable part has to do with level, not frequency accuracy.

I often find 1-2 substantial peaks within the passband of a subwoofer. Sometimes there are 3. I apply appropriate notch filters (usually from aprox 1/3 to 2/3 octave) *but* I also do not go for anywhere near flat, as these peaks may be room (modal) related and therefore they are: 1) not even across the space and 2) they require huge amounts of attenuation. Over-compensating robs the subwoofer of headroom, which they all need ample amounts of. So reducing the peaks a reasonable amount (6-10dB) smooths the subs out but does not go too far, I find.
Title: Re: Measurement Microphones
Post by: Art Welter on January 09, 2009, 12:52:10 pm
Tom,

Well, a “diamond-coated” diaphragm is close enough to “diamond sputtered” in my book.

I had never heard of diamond-coated diaphragms before, do you know of companies other than Peavey using the process?
Title: Re: Measurement Microphones-multiple measurements
Post by: Ivan Beaver on January 09, 2009, 01:23:14 pm
A very interesting thing to do when considering sub "eq" is to take a measurement for a good number of places out in the room, in typical listening positions.

You will see all sorts of interesting responses "pop up".

I generally use multiple mics and average them together and "eq" that-as a STARTING point.

I then look at each mic individually and see if anything is really odd and then determine if that mic position is a valid one-in terms of the other positions.

Lets say all the mics show a little hump at 60 Hz.  Except 1 that has a HUGE notch at 60Hz.  The average may be zero, but is that really the case? Rolling Eyes

Sometimes you have to dig a bit deeper.

Making it "right" for one person is pretty easy,  But making it "right" for a thousand or so is often quite a different matter.

But then again-I am preaching to the choir here Laughing  Laughing .
Title: Re: Measurement Microphones
Post by: Tom Young on January 09, 2009, 01:38:45 pm
No. And that's an interesting consideration.

First of all; I wonder what is the diaphragm substrate ? Is it plastic ? Is it (therefore) any less susceptible to environmental conditions than plain old plastic diaphragms ? Why did Peavey discontinue these ? Why did (apparently) no one else employ them in their microphones ?

(and while we're at it)

When Bruel & Kjaer, Neumann and others employ "sputtered gold" diaphragms, what is the substrate ?
Title: Re: Measurement Microphones
Post by: Dave Barnett on January 09, 2009, 06:25:10 pm
Last night a customer asked me why I had a nose hair trimmer on a stand...
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 09, 2009, 07:00:01 pm
 Laughing  Laughing  Laughing  Laughing  Laughing  Laughing  Laughing  Laughing  Laughing

Dave you almost owed me a new laptop then.

Charlie
Title: Re: Measurement Microphones
Post by: Tom Young on January 09, 2009, 07:12:18 pm
......somehow that sort of makes sense when you consider you are working to reduce *comb* filtering.

(I know that is pretty lame)
Title: Re: Measurement Microphones
Post by: John Roberts {JR} on January 09, 2009, 08:18:47 pm
For people who stick their nose where it doesn't belong?

JR
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 09, 2009, 09:26:37 pm
JR,

While your on this thread I wonder if you can shed any light on this Peavey ERO 10 measurement mic? its got the AMR branding on the mic and I know you were involved in that group at Peavey.

Charlie
Title: Re: Measurement Microphones
Post by: John Roberts {JR} on January 09, 2009, 09:48:26 pm
Charlie Jeal wrote on Fri, 09 January 2009 20:26

JR,

While your on this thread I wonder if you can shed any light on this Peavey ERO 10 measurement mic? its got the AMR branding on the mic and I know you were involved in that group at Peavey.

Charlie


While I didn't work on the transducer engineering, I was "AMR boy" back in my early  days.

The ERO-10 was not designed as a measurement mic but a recording mic, and they  sounded quite good (IMO) when used right. IIRC it was an omni.

AFAIK the capsule wasn't anything special, but they are generally quite flat up to 8 kHz or so, and while not uber flat much above that have usable response as high as you need for most recording.

Peavey needed a measurement mic when they started selling their early digitally controlled analog graphic EQ, so the ERO-10 got drafted, painted black, and presto it was a Peavey measurement mic.. I think the Peavey model had a different name (PV....something).

I kind of liked using one or two of them for overheads above a drum kit (in the studio).

JR


Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 09, 2009, 09:53:18 pm
Thanks for that JR,


Looks like the TR40 will have to earns its living a while longer then, although I'm pretty sure I can always find a use for the ERO 10.

Charlie
Title: Re: Measurement Microphones
Post by: John Roberts {JR} on January 09, 2009, 11:49:24 pm
Charlie Jeal wrote on Fri, 09 January 2009 20:53

Thanks for that JR,


Looks like the TR40 will have to earns its living a while longer then, although I'm pretty sure I can always find a use for the ERO 10.

Charlie


Not to disparage anybodies mic, but is suspect many low cost "reference" mics use off the shelf capsules and are not manually trimmed.  They are quite good stock at low-mid frequencies where it matters..

I can sell you a capsule for $1 that'll probably do OK (I use two in my tuner) but you'll need to wire it into a shell and connector and add a few sundry discrete components...

JR
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 10, 2009, 12:02:00 am
Once I'm back to full working capacity when the hernias fixed I'll go buy another M30 to replace my currently banana shaped one, some idiot dropped my bag over a 20' balcony and the rest of the contents bent it a little. Of course as usual no-one knew who it was that did it so I'm left with the cost so the back up TR40 will have to do.

Charlie
Title: Re: Measurement Microphones
Post by: Nick Hickman on January 10, 2009, 07:01:28 am
John Roberts  {JR} wrote on Sat, 10 January 2009 02:48

Peavey needed a measurement mic when they started selling their early digitally controlled analog graphic EQ, so the ERO-10 got drafted, painted black, and presto it was a Peavey measurement mic.. I think the Peavey model had a different name (PV....something).

Was it the PVR1?

The Peavey PVR2 is still available.  From the way it and its packaging look, one would guess it originates from the same place as the Behringer ECM8000.  I compared my PVR2 against my M30:

http://100dB.com/misc/pvr2.png

Nick
Title: Re: Measurement Microphones
Post by: Tom Young on January 10, 2009, 08:18:46 am
It appears my recollection was flawed. Sorry about that.
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on January 10, 2009, 09:05:25 am
Nick Hickman wrote on Sat, 10 January 2009 06:01

John Roberts  {JR} wrote on Sat, 10 January 2009 02:48

Peavey needed a measurement mic when they started selling their early digitally controlled analog graphic EQ, so the ERO-10 got drafted, painted black, and presto it was a Peavey measurement mic.. I think the Peavey model had a different name (PV....something).

Was it the PVR1?

The Peavey PVR2 is still available.  From the way it and its packaging look, one would guess it originates from the same place as the Behringer ECM8000.  I compared my PVR2 against my M30:

http://100dB.com/misc/pvr2.png

Nick



Looks like you would end up with a really warm sounding system.  That might be really nice for some applications, particularly smaller systems.
Title: Re: Measurement Microphones
Post by: John Roberts {JR} on January 10, 2009, 10:51:29 am
PVR1 sounds familiar.

JR
Title: Re: Measurement Microphones
Post by: Andy Peters on January 10, 2009, 01:44:24 pm
Charlie Jeal wrote on Fri, 09 January 2009 22:02

Once I'm back to full working capacity when the hernias fixed I'll go buy another M30 to replace my currently banana shaped one, some idiot dropped my bag over a 20' balcony and the rest of the contents bent it a little. Of course as usual no-one knew who it was that did it so I'm left with the cost so the back up TR40 will have to do.


As a rule, my microphones live in their own gig bag, and nobody but me touches that bag.

We were met by loaders at the front door of the theatre on New Year's Eve. They asked if we had any audio gear which they were required by contract to hump. I said, "Nope, nothing but baby stuff!" which they immediately understood once I took the kid out of the car. The nondescript mic bag was babied.

-a
Title: Re: Measurement Microphones
Post by: Ray A. Rayburn on January 10, 2009, 03:31:29 pm
Tom Young wrote on Fri, 09 January 2009 18:38

When Bruel & Kjaer, Neumann and others employ "sputtered gold" diaphragms, what is the substrate ?


I don't think Bruel & Kjaer makes any mics with gold sputtered diaphragms, but Neumann and many other firms do.  The gold sputtering is a way of applying a very thin layer (just a few atoms thick) of gold to the surface of a polymer (plastic) diaphragm in order to make it conductive enough for use in a condenser microphone.  Gold is used because it will not corrode.
Title: Re: One Measurement Microphone
Post by: Ray A. Rayburn on January 10, 2009, 03:53:31 pm
Josh Evans wrote on Wed, 24 December 2008 14:31


I have two of the mic cases as well.


That case appears to be the CigarCaddy 2-Stick (formerly Otter Box 3140) made right here in Fort Collins Colorado.

http://www.cigarcaddy.com/products/2_stick/

Pat Brown turned me on to them, and I now pack my SF101 and SF111 mics in these cases.

http://testmic.com/

Ray A. Rayburn
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 10, 2009, 04:58:54 pm
Andy Peters wrote on Sat, 10 January 2009 18:44

Charlie Jeal wrote on Fri, 09 January 2009 22:02

Once I'm back to full working capacity when the hernias fixed I'll go buy another M30 to replace my currently banana shaped one, some idiot dropped my bag over a 20' balcony and the rest of the contents bent it a little. Of course as usual no-one knew who it was that did it so I'm left with the cost so the back up TR40 will have to do.


As a rule, my microphones live in their own gig bag, and nobody but me touches that bag.

We were met by loaders at the front door of the theatre on New Year's Eve. They asked if we had any audio gear which they were required by contract to hump. I said, "Nope, nothing but baby stuff!" which they immediately understood once I took the kid out of the car. The nondescript mic bag was babied.

-a


Which would normally be the case for me, I had the M30 at FOH with me up on the balcony dropped FOH and put the M30 in my bag to then go back down onto stage and into to my workbox where it usually lives. Went to take a leak came back and everything had been moved, and "Mr Nobody" had carried my bag Mad FWIW it was the large armoured thermos flask that did the damage on impact.

Charlie
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on January 10, 2009, 05:06:31 pm
Yea but they are cheaper from Rational Acoustics and have a fancy RA logo on them too.
Title: Re: Measurement Microphones
Post by: Charlie Jeal on January 10, 2009, 05:10:46 pm
Harry I wish the shipping rates to the UK weren't quite so silly though, or at least the ones the website quotes anyway.

Charlie
Title: Re: Measurement Microphones
Post by: Daniel Ellis on January 10, 2009, 05:23:52 pm
i just received my MICro case from rational acoustics this morning.   I felt like i got ripped off at first when I saw the cigar daddy logo, but then I looked it up and realized that I paid less through RA!


Title: Re: Measurement Microphones
Post by: Arthur Skudra on January 10, 2009, 08:47:42 pm
Charlie Jeal wrote on Sat, 10 January 2009 17:10

Harry I wish the shipping rates to the UK weren't quite so silly though, or at least the ones the website quotes anyway.

Charlie

Charlie, you should talk to Karen over at Rational Acoustics, she can send it by postal service instead of UPS, it'll save you a bundle on shipping stuff internationally.  I know I did with a bunch of cases I got recently from them.  In addition to the excellent Micro cases they sell, I really like their zipper bags as well.
Title: Re: Measurement Microphones
Post by: Ray A. Rayburn on January 10, 2009, 11:45:21 pm
HarryBrillJr. wrote on Sat, 10 January 2009 22:06

Yea but they are cheaper from Rational Acoustics and have a fancy RA logo on them too.


I provided the link to Cigar Caddy since they are the manufacturer.  However if you Google the item you will find cigar places selling them for as little as $13 - 15.  No matter who you buy it from, it is a good quality case that fits most measurement mics perfectly.
Title: Cheap Cigar Cases
Post by: Mac Kerr on January 10, 2009, 11:52:35 pm
Ray A. Rayburn wrote on Sat, 10 January 2009 23:45

HarryBrillJr. wrote on Sat, 10 January 2009 22:06

Yea but they are cheaper from Rational Acoustics and have a fancy RA logo on them too.


I provided the link to Cigar Caddy since they are the manufacturer.  However if you Google the item you will find cigar places selling them for as little as $13 - 15.  No matter who you buy it from, it is a good quality case that fits most measurement mics perfectly.

Here is one under $12.

What is the inside dimension of these? It looks too small for my TC30K.

Mac
Title: Re: Cheap Cigar Cases
Post by: BruceOlson on January 11, 2009, 03:11:12 am
Mac Kerr wrote on Sat, 10 January 2009 22:52

What is the inside dimension of these? It looks too small for my TC30K.


Yea, that was my concern as well.  The site that Ray linked to showed them as 7.88in internal. Even for my Josephson's that seems a bit close to the capsule for me.  I use the Pelican 1060 cases for my mics.  The nice thing about the cigar caddies is the foam inserts, with the 1060 I had to do the pick and pluck thing and dig into my foam stock for the cover.

The 1060 is 8.25" x 4.25" x 2.25" internal.
Title: Re: Cheap Cigar Cases
Post by: HarryBrillJr. on January 11, 2009, 07:24:48 am
Mac Kerr wrote on Sat, 10 January 2009 22:52

Ray A. Rayburn wrote on Sat, 10 January 2009 23:45

HarryBrillJr. wrote on Sat, 10 January 2009 22:06

Yea but they are cheaper from Rational Acoustics and have a fancy RA logo on them too.


I provided the link to Cigar Caddy since they are the manufacturer.  However if you Google the item you will find cigar places selling them for as little as $13 - 15.  No matter who you buy it from, it is a good quality case that fits most measurement mics perfectly.

Here is one under $12.

What is the inside dimension of these? It looks too small for my TC30K.

Mac


They will not fit the full length Earthworks Mics.  They do fit just about everything else.  They also tested the water resistance.  If I remember right the bag they are having made fits the M30.  I wish I could get a 6 pack case long enough to fit the M30 but only as thick as these little 2 pack cases.

The larger case will fit the M30 diagonally and is still smaller than the case EW provides, and a whole lot smaller than the case dbx provides.
Title: Measurement Microphones
Post by: Steve Bunting on February 10, 2009, 05:56:41 am
Has anyone got any experience with the Earthworks M23, or the S30 which Rational sells? Is this the same mic with different names? How do they compare to an M30?
Title: Re: Measurement Microphones
Post by: Brad Weber on February 10, 2009, 09:31:08 am
Steve Bunting wrote on Tue, 10 February 2009 05:56

Has anyone got any experience with the Earthworks M23, or the S30 which Rational sells? Is this the same mic with different names? How do they compare to an M30?

I have a couple of the M30S mics that these models replace.  I believe the M23 and S30 are essentially the same mic.  Pretty much a more compact version of the M30 with a flat response to 23kHz instead of 30kHz, at least that was the response I got from Earthworks prior to purchasing my mics and the specs seem to agree with that.  I think it is a reasonable option between the entry level and high end mics for system tuning, which is exactly why I bought mine.
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 04, 2010, 03:20:48 pm
Bob McCarthy wrote on Mon, 22 December 2008 15:26

I own 8 Earthwoks M30s. They are sufficient for my needs, although I probably would have bought DPA 4090 series mics had they been on the market at the time I bought mine.



Hello Bob -
I bought your book - "Sound Systems:  Design and Optimization," and appreciate it.

I'm wondering if you would comment on why you have bought DPA 4090 as opposed to M30 if you were to buy (in Dec '08 Smile ) again.  The more I've read, the more I'm inclined to agree, based mainly on the fact that the 4090 has a nickel foil diaphragm.  

Thanks,
Grant  
Title: Re: Measurement Microphones
Post by: Tom Young on February 04, 2010, 05:42:20 pm
Perhaps what Bob had in mind is that the Earthworks microphones have plastic diaphragms which can be subject to changes in response when exposed to high temps, such as being carried in a closed car/trunk during a hot summer day. Metal diaphragms are inherently more stable. I believe these two mic's cost about the same.

FYI - here are some other mic's that are worth considering:

The Soundfirst SF101 is a titanium diaphragm measurement mic that appears to be just as good as the DPA and Earthworks and is in the same ballpark price range ($750.00).

See: http://testmic.com/

The NTI (Neutric Test Instruments) M2210 mic that is available with their XL2 measurement system is also a titanium diaphragm measurement mic with extremely good (Class-1) specs. Costs a bit more ($1100.00). They also offer a Class-2 mic (M4260) that has very respectable specs for sound system optimization and costs appreciably less than the others ($450.00).

See: http://www.nti-audio.com/

(or more directly)
http://www.nti-audio.com/Home/Products/Microphones/M4260M221 0/tabid/272/Default.aspx

Bruel and Kjaer has a new and very interesting measurement mic, the 4961, with titanium diaphragm and touted to be "multi-field". It is closer to the cost of a DPA 4007 (ballpark: $1400.00). Note: it appears to not be compatible with standard phantom power and XLR inputs.

See: http://www.bksv.com/doc/bp2220.pdf

FWIW
Title: Re: Measurement Microphones
Post by: Bob McCarthy on February 04, 2010, 06:02:33 pm
I have indeed had stability issues with my M30's, both over the long haul and from day to day. At this point I go through a level calibration exercize every day that I use them. Perhaps this is due to mylar in the diaphragm - perhaps not. I am not qualified to do more than conjecture in the field of microphone design.

The reason I stated that I would have gone with ( and may at some in the future go with) the low cost DPA's is more relational, than purely technical. I have used Bruel & Kjaer (and now DPA) mics so much over the years and been let down so few times..........so few that I can hardly think of even once. I think of them as digital mics - 1 or 0 - working perfectly or dead (and this is usually easy to spot with the crushed head.)

I just have so much confidence in their mics that I would feel confident relying on them - and inevitably we RELY on mics. But, all that said - i have very little experience directly with the 4090 mics, so the book is still open.

These other mics Tom shows look interesting indeed but for me its DPA's gig to lose.

6o6
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 04, 2010, 06:17:04 pm


Tom - Thanks for clarifying that M30's have plastic diaphragms.  I suspected as much, but could not verify.  Until very recently, the SF101 was at the top of my list for the day when I could afford one.  Then I discovered that the DPA 4090 and the 4007 both have nickel foil diaphragms.  And if I read the material correctly, they both are pre-aged with temperature.  It leads me to wonder why the 4007 would enjoy the reputation of being so robust, but not the 4090.  From what little I know, titanium seems like it should be a better material, but how do the DPA's stack up durability-wise next to the SF101?

Here's some interesting info on mic construction:   http://www.dpamicrophones.com/en/Microphone-University/Techn ology-Guide/Microphone%20Stability.aspx

I hadn't heard of the NTI mics.  I presume the M4260 is a plastic diaphragm?  

Bob - Thanks again for your thoughts.

Grant

Title: Re: Measurement Microphones
Post by: Tom Young on February 04, 2010, 06:25:03 pm
Aha. Assurance. Makes sense to me Wink

I agree with your conclusion that they eiher work (perfectly) or not (at all).

In about 1997 I bought a used 4007 and when visiting a job site in greater Toronto the guys from DPA offered to lend me a 4007 and test mine while I was up there. It was "perfect", they found.

I also recall one 4007 that you and I had in the kit we rented for Dijon that was sorta "mangled" looking. Low and behold.....it didn't work.

So there you are.
Title: Re: Measurement Microphones
Post by: Tom Young on February 04, 2010, 06:36:29 pm
Grant-

All Earthworks microphones employ plastic diaphragms. I am not certain about Earthworks, but usually the better (and more expensive) plastic diaphragm mic's have pre-treated diaphragms. This helps but does not completely mitigate the need to ensure that they are not exposed to high temps.

I do note that anyone who leaves their measurement mic's in a car trunk in Death Valley during the summer is kind of asking for trouble. No matter what the diaphragms are made of Wink

I will have an answer on the NTI M4260 by Monday.

Bruel and Kjaer alludes to their new titanium diahragm as not being susceptible to magnetic fields. So how are plastic or spun-gold (4007) diaphragms susceptible to magnetic fields ?

Hmmm.
Title: Re: Measurement Microphones
Post by: Tom Young on February 08, 2010, 04:27:24 pm
Official word from NTI:

The M2210 (which is 1/2") has a titanium diaphragm

The M2460 (which is 1/4") has a plastic diaphragm.

Based on price, this is not surprising.
Title: Re: Measurement Microphones
Post by: Tom Young on February 09, 2010, 05:51:54 pm
Thanks, Ray. I stand corrected.

Curious: what is the 4007 diaphragm made from ?
Title: Re: Measurement Microphones
Post by: Bob McCarthy on February 09, 2010, 06:11:58 pm
100% pure Unobtanium.

6o6
Title: Re: Measurement Microphones
Post by: Brandon G Romanowski on February 09, 2010, 06:25:19 pm
Has anyone heard about a new Audix measurement mic?
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 09, 2010, 06:38:34 pm
This is all I can find on the new Audix:  

http://www.youtube.com/watch?v=Fizlhpuhm8g

If the diaphragm is preshrunk, I'd say it should be a real winner.  If not, it's just a plain winner.  

Grant
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 09, 2010, 06:48:07 pm
According the manual, the DPA 4007 is "nickel foil which has been coated with an ultra-thin polymer layer for optimum corrosion resistance."
http://www.dpamicrophones.com/sitecore/shell/Controls/Rich%2 0Text%20Editor/~/media/PDF/Download/Users%20Manuals/4004%204 007.pdf

As near as I can tell, the 4090 is made of the same stuff. I think it's safe to say that both the 4007 and 4090 are actual metal diaphragm, not plastic sputtered with nickel.  If this is incorrect, I'm open to correction.  

Grant
Title: Re: Measurement Microphones
Post by: Andy Peters on February 09, 2010, 07:26:14 pm
Brandon G Romanowski wrote on Tue, 09 February 2010 16:25

Has anyone heard about a new Audix measurement mic?


After I sent my two TR40s in for test (April of last year), I was told by the Audix test engineer with whom I dealt that they were working on a new measurement mic that was supposed to be as good as the Earthworks 30 but for less money. He said he hoped that it would be released in about six months but otherwise made no guarantees.

Obviously it is not ready for prime time.

-a
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 09, 2010, 07:45:52 pm
Andy Peters wrote on Tue, 09 February 2010 18:26

...I was told by the Audix test engineer with whom I dealt that they were working on a new measurement mic that was supposed to be as good as the Earthworks 30 but for less money....
-a


If this is the case, then the diaphragm will be preshrunk, and comparable to an m25, (25k bandwidth) if there were such a thing.  Again, if this is the case, it's very good news for consumers.

Grant  
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on February 11, 2010, 01:55:15 am
Rational is all over it.  I think list is around $300. but don't quote me on that.  It will blow away the old Audix.  Earthworks is going to have to step it up or lower there prices me thinks, or Harry might be getting a matched set of Audix instead of EW.
Title: Re: Measurement Microphones
Post by: HarryBrillJr. on February 11, 2010, 02:06:35 am
Andy Peters wrote on Tue, 09 February 2010 18:26

Brandon G Romanowski wrote on Tue, 09 February 2010 16:25

Has anyone heard about a new Audix measurement mic?


After I sent my two TR40s in for test (April of last year), I was told by the Audix test engineer with whom I dealt that they were working on a new measurement mic that was supposed to be as good as the Earthworks 30 but for less money. He said he hoped that it would be released in about six months but otherwise made no guarantees.

Obviously it is not ready for prime time.

-a



They showed it at NAMM.

index.php/fa/28032/0/
Title: Re: Measurement Microphones
Post by: Grant Conklin on February 11, 2010, 02:19:31 am
Harry -
A few posts back is the youtube video at namm - here it is again:  http://www.youtube.com/watch?v=Fizlhpuhm8g

It is true that list is $299, at least according to the video - these things seem like they are subject to change until the product is actually released.  

Do you happen to know anything about the capsule?  Is it pre-shrunk?  

Thanks,
Grant
Title: Re: Measurement Microphones
Post by: Grant Conklin on March 03, 2010, 09:31:42 pm
...And now the TM-1 is on the Audix website:  http://www.audixusa.com/docs/products/TM1.shtml

If it isn't obvious by now, I'm a little obsessed with measurement mics, (and construction levels - go figure) particularly with what their diaphragms are made of, since I don't know of any other way to really gauge long term stability other than reports from the field, which can be spotty.  So, I sent Audix an e-mail the other day to ask about the TM-1 diaphragm, and this is what they said:  

After the TM-1 is in day to day use we will see the real quality, stability, etc. ,  it is difficult to predetermine accurately the performance of any product until it has been in use.  It is my belief that the quality and performance of the TM1 (short term and long term) should be evaluated by those that are using the product.
“Pre-aged and pre-shrunk” to one degree or another most diaphragms are conditioned in the manufacturing process."


FWIW.  

And here's another gem I haven't heard anyone else talking about.  The Avantone AK-Type VII.  Sports a nickel diaphragm (I only know because I asked) and sells for $499.  Sweet.  
http://www.avantelectronics.com/AK-Type%20VII.htm

Grant
Title: Re: Measurement Microphones
Post by: Tom Young on March 04, 2010, 09:43:03 am
Type VII ?  I wouldn't use anything lower than a Type-II  Very Happy

Looks like a possible "find". Know anything about the company, reliability of their products, service/warranty support, etc ?

Thanks, Grant.
Title: Re: Measurement Microphones
Post by: Grant Conklin on March 04, 2010, 10:41:15 am
Hi Tom -
The only thing I know about the company is that their recording mics are being very well received by top studios and engineers.  I'm selling a CV12 which will arrive today or tomorrow, so I'll get to see the quality of their product firsthand.  
http://www.avantelectronics.com/CV-12.htm

Grant
Title: Re: Measurement Microphones
Post by: Timo Beckman on March 05, 2010, 12:10:48 pm
I'm using a matched set of 6 x DPA 4007sim micr. The 4090/91 is also ok i own 10 pieces of them but i use them on stage . I somethimes use the 4007 on stage but there a little to expensive to have them trown around by musicians or stage people . I used a 4007 in a base drum a couple of times . That was a eye opener on low end specialy for the subs in that configuration of PA

http://cid-5933da57cf499561.skydrive.live.com/browse.aspx/Al le%20DPA%20mic%5E4s%20%5E5op%203%20na%5E6%20die%20ik%20heb
Title: Re: Measurement Microphones
Post by: Bob McCarthy on March 05, 2010, 03:25:32 pm
Timo,
That is an impressive array of mics you have there! I am having serious mic envy, stuck here with my cheapo Earthworks wannabes. Embarassed

The 4007 is capable of extremely high SPLs before overload so I am not surprised that it would make an impressive kick drum mic.

6o6


Title: Re: Measurement Microphones
Post by: Josh Ricci on March 05, 2010, 03:49:19 pm
Grant Conklin wrote on Wed, 03 March 2010 20:31[/color

 

And here's another gem I haven't heard anyone else talking about.  The Avantone AK-Type VII.  Sports a nickel diaphragm (I only know because I asked) and sells for $499.  Sweet.  
http://www.avantelectronics.com/AK-Type%20VII.htm

Grant


I'm about this close to ordering a set of M30's, but this looks very interesting. Is it me or does it look almost too good to be true? I'm hesitant because I've never heard of them.
Title: Re: Measurement Microphones
Post by: Tamas Tako on March 05, 2010, 03:57:32 pm
Hi all,

I dot know if anyone mentioned it before or not.
My favorite measuring mic is (and its also quite affordable) the one what comes with the Klark DN6000 analyser.
It also can be ordered as a mic alone.
it is dead flat, and it always comes with a measured response graph (measured with B&K equipment)

any toughts?

Thanks,

Tamas
Title: Re: Measurement Microphones
Post by: Too Tall (Curtis H. List) on March 05, 2010, 04:05:27 pm
Tamas Tako wrote on Fri, 05 March 2010 15:57

Hi all,

I dot know if anyone mentioned it before or not.
My favorite measuring mic is (and its also quite affordable) the one what comes with the Klark DN6000 analyser.
It also can be ordered as a mic alone.
it is dead flat, and it always comes with a measured response graph (measured with B&K equipment)

any toughts?

Thanks,

Tamas



Hey Tamas,
It is great to hear from you again.

Please send me an email to my current email-

curtislist@gmail.cxom

remove "x"

Thanks.
Title: Re: Measurement Microphones
Post by: Timo Beckman on March 05, 2010, 04:40:11 pm
at 606
Thanx for the compliment i'm realy happy with them . But without the seminar in Montabauer from U and the one from MAGU at Grisby in Italy it would be just another set of mic's and now it's a serious tool in my work .
Title: Re: Measurement Microphones
Post by: Too Tall (Curtis H. List) on March 05, 2010, 04:50:46 pm
Hi Bob,
Many of the measurement programs made for speaker design for both Pro and home DIY were able to import a deviation file.
Not just a couple of points for SPL, but up to 300 points including phase for each point.

When using cheaper mics that are not flat in the first place it makes sense to me that measurement programs should have the capability to import deviation over 300 points or more.


Bob McCarthy wrote on Mon, 22 December 2008 16:26

I own 8 Earthwoks M30s. They are sufficient for my needs, although I probably would have bought DPA 4090 series mics had they been on the market at the time I bought mine. They are now 5 years old. 2 of them will go back for rework shortly.

They drift in level over time and as a result I calibrate them at every job.



Also I can see that you will have drift over time, but having it to the point where you need to calibrate every time you use the program surprises me.
Once you calibrate a mic does the measurement program you are using fail to save that information file when you quit the program?
I understand it drifting over a year or two, but it should not drift worth mentioning by the time you use the program again (30 days)?

Bob McCarthy wrote on Mon, 22 December 2008 16:26


I never do any work with a single mic so for me relative level and freq response are more critical parameters than absolute freq response.



I have not kept up so I don’t know how many programs that can use deviation files can use multiple microphones. I don’t believe Praxis will add multiple mics, but it might happen.
I have not checked Clio or PHS Spectraplus, etc

Note: People like Kim Giardin and others have been calibrating mics for more than a decade.
Typical charge was about $25 each. Once a year is usually enough and inexpensive.

Bob McCarthy wrote on Mon, 22 December 2008 16:26


As for the earlier question re the B&K calibrator - it SHOULD work with the M30 adaptor. Calibrators are made to a standard and different mics have a specific adaptor mechanism to fit that.

Finally, at a recent SIM school in Germany a guy pulled out his Beringer mic and we compared it to the DPA 4007 using a dual mic transfer function. Everyone was prepared for a big laugh but the 25 cent mic did very well (this is the second time I have seen this so I was not too shocked.) So as much as I love to use Beringer as a punch line I will have to hold back some times and go with my old standby: Bose.


I posted the deviation file for the Behringer ECM8000 as a graph on the LAB more than once.
One mistake made is looking at a phase difference up above 16kHz and thinking the mic is bad when all you need to do is add a couple of micro seconds for flat delay and it look wonderful.

Once a calibration file is made and used it is very difficult to see the difference between a top line ACO that was used to calibrate it in the first place and this $40 mic. I know this from use.

Where I would worry (other then drift over time) is how consistent is it off axis. This should depend on the physical size and shape of the mic body, correct?


Title: Re: Measurement Microphones
Post by: Tamas Tako on March 05, 2010, 04:58:36 pm
Too Tall (Curtis H. List) wrote on Fri, 05 March 2010 22:50


Where I would worry (other then drift over time) is how consistent is it off axis. This should depend on the physical size and shape of the mic body, correct?





This is exactly why I love my Klark 6051 mic, as it has an 1/4 inch diameter...
the factory measurement shows a +/-0.25dB deviation from dead flat from 20Hz to 20kHz.
I have also an older (12 years old) which I just checked with a B&K pistophon ,and it was still just 0.2dB shifted in level....

Not bad...

Cheers,

Tamas
Title: Re: Measurement Microphones
Post by: Bob McCarthy on March 05, 2010, 05:38:36 pm
Too Tall,

I agree that deviation files are well and good and can really help moving between mics without a brain reset.

My SIM3 has level deviation compensation and that is good up to a point............. and the point is that some of my aged (7 years and many miles) mics don't reliably hold their sensitivity steady overnight.  At this point my confidence level is less than perfect - and therefore I do a daily calibration.

Bottom line is I need to send them ALL in for snip snip here and a snip snip there and a couple of la-di-da's - or give up on them and get a new set of......????????

I would never (and have never) dialed in sensitivity numbers of multiple based on what they say on the box. That is just a 1 kHz spec. Too loose. I match multiple mic levels based on as wide a freq range as possible.
Title: Re: Measurement Microphones
Post by: Tom Young on March 06, 2010, 01:41:39 am
They don't appear to be making the DN6000 anymore.

If I recalll correctly, the provided 6051 mic is one of the generic plastic diaphragm mic's that looks like the DBX measurement mic, as well as those sold by Sencore for their audio multitesters (formerly AudioToolbox).

Like all of the Chinese made plastic diaphragm mic's, the quality depends on the diaphragm (one can buy really good ones, so-so ones and mezz-a-mezz ones - these are tested and sorted after manufacture) and the electronics, which I think are either specified by the branded manufacturer and supplied by the mic manufacturer (in China) or are installed by the branded manufacturer after delivery.

I appears that (when they made the DN6000) KT measured and calibrated this mic.

If it works for you, Tamas, that's great.
Title: Re: Measurement Microphones
Post by: Tom Young on March 06, 2010, 01:45:35 am
Grant-

Intriqued by the allure of a reasonably priced nickel-diaphragm measurement mic, I queried Avant Electronics and they said:

"Thanks so much for the email & interest in the AK-Type Vii.
It would probably be a very nice measurement mic for you although we don't lay claim to it as such..."

Hmmmm. I will try to get one to play with.

But maybe the search goes on.
Title: Re: Measurement Microphones
Post by: Tom Young on March 06, 2010, 02:00:43 am
If the Avant AK-Type VII turns out to not be viable (or worth the risk) then I suggest you take a look at the already mentioned Audix MK1.

They are supposed to be in production by April and I have not evaluated one (yet). But it looks promising as a lower cost, decent measurement mic.

http://www.audixusa.com/docs/products/TM1.shtml
Title: Re: Measurement Microphones
Post by: Grant Conklin on March 06, 2010, 02:27:48 am
Tom Young wrote on Sat, 06 March 2010 00:45


...I queried Avant Electronics and they said:

"Thanks so much for the email & interest in the AK-Type Vii.
It would probably be a very nice measurement mic for you although we don't lay claim to it as such..."




That's weird.  It seems to have everything you'd want in a measurement mic, and they claim it's  
"compared directly to the very finest European omni reference mics....  used for critical acoustical calibration measurements and  testing...  Complies with IEC651 TYPE 1 STANDARDS...  Free-field Microphone (calibration grade)...  "
But they don't claim it to be a measurement mic?  

The new TM-1 definitely scores high in the looks department.  In looking at the frequency response graph (if those can be trusted) it doesn't appear to have much over the Beyer MM1, which I have and like.  

Grant
Title: Re: Measurement Microphones
Post by: Tom Young on March 06, 2010, 07:24:16 am
Quote:

That's weird. It seems to have everything you'd want in a measurement mic, and they claim it's "compared directly to the very finest European omni reference mics.... used for critical acoustical calibration measurements and testing... Complies with IEC651 TYPE 1 STANDARDS... Free-field Microphone (calibration grade)... "  But they don't claim it to be a measurement mic?


I was just as taken aback. Maybe it's an issue of QC. Specifically, do they have the means to produce the same, exact performance from mic to mic to mic.

I don't know.
Title: Re: Measurement Microphones
Post by: BruceOlson on March 06, 2010, 03:05:23 pm
Grant Conklin wrote on Sat, 06 March 2010 01:27

Tom Young wrote on Sat, 06 March 2010 00:45


...I queried Avant Electronics and they said:

"Thanks so much for the email & interest in the AK-Type Vii.
It would probably be a very nice measurement mic for you although we don't lay claim to it as such..."




That's weird.  It seems to have everything you'd want in a measurement mic, and they claim it's  
"compared directly to the very finest European omni reference mics....  used for critical acoustical calibration measurements and  testing...  Complies with IEC651 TYPE 1 STANDARDS...  Free-field Microphone (calibration grade)...  "


That makes me suspect it even more, IEC 651 was renamed to 60651 before it was replaced by IEC 61672 in 2002. So they comply with an obsolete standard. Who cares Rolling Eyes , they sure seem not to know what they are talking about.
Title: Re: Measurement Microphones
Post by: Ivan Beaver on March 06, 2010, 03:16:58 pm
Bob McCarthy wrote on Fri, 05 March 2010 17:38

My SIM3 has level deviation compensation and that is good up to a point............. and the point is that some of my aged (7 years and many miles) mics don't reliably hold their sensitivity steady overnight.  At this point my confidence level is less than perfect - and therefore I do a daily calibration.


I would never (and have never) dialed in sensitivity numbers of multiple based on what they say on the box. That is just a 1 kHz spec. Too loose. I match multiple mic levels based on as wide a freq range as possible.

My mics are getting the same way-but hopefully I will be getting a new set soon. Very Happy

Whenever I am doing a system alignment I save a trace with the mic of the lowest output (my purple one).  I then set up each of hte other mics in the same position and adjust levels so the curves lay on top of each other.  Agreed broadband is much better than a single freq.

This not only helps to compensate for the various mic levels-but also any changes that may have occured in the mic preamp (in my case a MOTU 8 pre).

I use Systune and it will keep the levels for each of the different mics as I jump around during an alignment.
Title: Re: Measurement Microphones
Post by: Johnny Diaz on November 02, 2011, 02:59:17 pm
Since this thread is a few years old and I'm about to purchase a few mics in the $600-$700 range which mic would give best to work with Smaart?
Title: Re: Measurement Microphones
Post by: Mac Kerr on November 02, 2011, 03:14:41 pm
Since this thread is a few years old and I'm about to purchase a few mics in the $600-$700 range which mic would give best to work with Smaart?

What kind of work are you doing that you need that many mics of that quality? If you are a speaker designer doing critical measurements as part of the design process, or if you are doing installations that require that the measurements use type 1 measurement mics you will want mics of at least that level, probably significantly more expensive.

If you are doing system alignment and eq on touring systems you do not need multiples of that level of microphone. I have one Earthworks mic, and 3 Rational Acoustics mics. That's one at the $500 level, and three at the $80 level. Currently RA has an introductory offer on the ISEMcon EMX-7150 (http://www.rationalacoustics.com/store/microphones/isemcon-emx-7150.html) which is a very good value.

There are lots of useful mics available from the low of the RA 420 at $80, to several thousand dollars. It will be easier to recommend one if you give some guidance on how you intend to use it. The price range it may fall in should be a result of a search for a mic that fulfills a functional spec, not the other way around.

Mac
Title: Re: Measurement Microphones
Post by: Johnny Diaz on November 02, 2011, 03:26:41 pm
What kind of work are you doing that you need that many mics of that quality? If you are a speaker designer doing critical measurements as part of the design process, or if you are doing installations that require that the measurements use type 1 measurement mics you will want mics of at least that level, probably significantly more expensive.

If you are doing system alignment and eq on touring systems you do not need multiples of that level of microphone. I have one Earthworks mic, and 3 Rational Acoustics mics. That's one at the $500 level, and three at the $80 level. Currently RA has an introductory offer on the ISEMcon EMX-7150 (http://www.rationalacoustics.com/store/microphones/isemcon-emx-7150.html) which is a very good value.

There are lots of useful mics available from the low of the RA 420 at $80, to several thousand dollars. It will be easier to recommend one if you give some guidance on how you intend to use it. The price range it may fall in should be a result of a search for a mic that fulfills a functional spec, not the other way around.

Mac

Mac,

I will be doing system alignments and eq on fixed and mobile systems.

Johnny
Title: Re: Measurement Microphones
Post by: Mac Kerr on November 02, 2011, 03:43:46 pm
Mac,

I will be doing system alignments and eq on fixed and mobile systems.

Johnny

If you plan on doing multi mic setups, get 1 real good mic, and a few lesser mics. The differences between the great mics and the less great mics generally fall above 10kHz where we do very little in the way of system eq. In the 100Hz-10kHz range even quite cheap mics will perform as well as $1k mics.

Since your original post implied a budget in the $1800-$2100 range you may want 1 Earthworks M30, a fairly rugged measurement mic, and 2 or 3 of the ISEMcons I linked to previously. Or there may be some other upper mid priced and lower mid priced mics that tickle your fancy.

Your budget, and the care they require probably argues against something like a DPA 4007 at $1700, and although they may be serviceable, your pride may dictate better than the Behringer ECM8000 (http://www.zzounds.com/item--BEHECM8000).

HERE IS SOME INFO ON TEST MICS (http://www.testmic.com/).

Mac

Title: Re: Measurement Microphones
Post by: Chris Johnson [UK] on November 03, 2011, 08:13:17 am
AFAIK, the Lectrosonics TM400 is the only wireless currently available that is suitable for test and measurement.


Actually, the Line6 V70 system is perfect for test & measurement. It operates in 2.4Ghz, so best use 5ghz for your wireless control applications. But its virtually as flat as a piece of wire (verified on the workbench) and has negligible latency (again, easily measured and compensated for).

The downside is that its designed for lav mics so you need to use a mic that is internally powered (A-la NTI MiniSPL mic) or a little inline PSU, but its a steal for 350!

We cant buy the Lectro stuff in the UK, so its pretty much the only option for us.

Chris
Title: Re: Measurement Microphones
Post by: Hayden J. Nebus on November 05, 2011, 10:16:15 pm
If you plan on doing multi mic setups, get 1 real good mic, and a few lesser mics. The differences between the great mics and the less great mics generally fall above 10kHz where we do very little in the way of system eq.

FWIW, in a qick and dirty dual mic TF test, my TM1 stood shoulder to shoulder with a B&K 4007 right up to 10kHz, where it took a -6dB dive. The TM1 looks to be about -3dB , and the 4007  maybe+ 1.5 dB @10k on their respective datasheets. Given my application (fixed rig), for the price of a couple 58s (maybe betas) it's hard to beat that with a stick. I trust the QC at Audix a schosh more than at Uli & Co.

Thanks to Russ from TTE for lending his B&K for a minute.     
Title: Re: Measurement Microphones
Post by: Karl Winkler on November 07, 2011, 10:40:57 am

We cant buy the Lectro stuff in the UK, so its pretty much the only option for us.


Lectrosonics IS available in the UK, but the R400A receiver is not. You could use an SRa receiver or a Venue system with the HM transmitter - both are UK compliant. Check with Raycom and MTA.
Title: Re: Measurement Microphones
Post by: Gert Sanner on January 01, 2012, 05:19:18 am
I like the Beyerdynamic, but I havnt found an adaptor for pistonphones.

I can help with a link.

http://winaudiomls.de/joomla/index.php/en/shop/category/view/7 (http://winaudiomls.de/joomla/index.php/en/shop/category/view/7)
Title: Re: Measurement Microphones
Post by: Sean Barry on March 18, 2013, 09:18:11 pm
Just to be clear, I recently purchased a DBX Drive Rack 260. Will a Behringer ECM8000 be good enough to do basic RTAing in small bar gigs? As it costs half as much as the DBX mic? Thanks.

Actually, the Line6 V70 system is perfect for test & measurement. It operates in 2.4Ghz, so best use 5ghz for your wireless control applications. But its virtually as flat as a piece of wire (verified on the workbench) and has negligible latency (again, easily measured and compensated for).

The downside is that its designed for lav mics so you need to use a mic that is internally powered (A-la NTI MiniSPL mic) or a little inline PSU, but its a steal for 350!

We cant buy the Lectro stuff in the UK, so its pretty much the only option for us.

Chris
Title: Re: Measurement Microphones
Post by: David Sturzenbecher on March 18, 2013, 10:23:11 pm
Just to be clear, I recently purchased a DBX Drive Rack 260. Will a Behringer ECM8000 be good enough to do basic RTAing in small bar gigs? As it costs half as much as the DBX mic? Thanks.

Sean.
I would start a new thread to ask your question as it has very little to do with the topic of this discussion.