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Author Topic: Suggestions for SMAART measurement mic.  (Read 3194 times)

Ivan Beaver

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Re: Suggestions for SMAART measurement mic.
« Reply #10 on: January 29, 2017, 10:05:55 am »



But i wrote what my needs are. Live RTA flattening some club PA systems with pinknoise.
Phase aligning different boxes. Trying to flatten my yamaha HS7's at home since my room is not treated.


If you are using Smaart as an RTA, then it really doesn't matter what measurement type mic you are using.

RTA is the wrong tool.  The dual transfer function is a MUCH better tool.

When you are talking about "phase aligning boxes", again it doesn't matter what mic you are using.

You mic could be TOTALLY off, but you are not interested in the phase of the mic.  Only the phase difference of the boxes.

So the boxes will have the same phase offset-no matter what the phase response of the mic is.

You are looking for RELATIVE phase difference-not ABSOLUTE phase response.
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Eugen Jeličić

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Re: Suggestions for SMAART measurement mic.
« Reply #11 on: January 29, 2017, 10:16:25 am »

If you are using Smaart as an RTA, then it really doesn't matter what measurement type mic you are using.

RTA is the wrong tool.  The dual transfer function is a MUCH better tool.

When you are talking about "phase aligning boxes", again it doesn't matter what mic you are using.

You mic could be TOTALLY off, but you are not interested in the phase of the mic.  Only the phase difference of the boxes.

So the boxes will have the same phase offset-no matter what the phase response of the mic is.

You are looking for RELATIVE phase difference-not ABSOLUTE phase response.

Well while the show is on the run. RTA is really practical just to see what is happening in the room. It can be helpfull to identify some mistakes in the general mix balance together with listening. But for that use, tohether with identifying feedback frequencies if problems occur during the show. Honestly, an SM57 is good enough...

For pinknoise flattening before the soundscheck a good measurement microphone is important but i tought the simple SMAART RTA analyzer is the right tool.
Why would the dual transfer function work better?

Talking about the phase response. Well tehnicaly yes you are right. The point is phase aligning different boxes in the segment where the crossover point overlaps. That means relative phase aligning in relation to eacother. Which again means that even a 57 would be good enough for this purpose since it's just a tool for comparing phase response of different boxes / it's used to measure relative phase. 
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Ivan Beaver

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Re: Suggestions for SMAART measurement mic.
« Reply #12 on: January 29, 2017, 11:57:27 am »

Well while the show is on the run. RTA is really practical just to see what is happening in the room. It can be helpfull to identify some mistakes in the general mix balance together with listening. But for that use, tohether with identifying feedback frequencies if problems occur during the show. Honestly, an SM57 is good enough...

For pinknoise flattening before the soundscheck a good measurement microphone is important but i tought the simple SMAART RTA analyzer is the right tool.
Why would the dual transfer function work better?

Talking about the phase response. Well tehnicaly yes you are right. The point is phase aligning different boxes in the segment where the crossover point overlaps. That means relative phase aligning in relation to eacother. Which again means that even a 57 would be good enough for this purpose since it's just a tool for comparing phase response of different boxes / it's used to measure relative phase.
During the show, I would agree that in many cases an RTA is the best tool-but what are you actually doing with that tool?  Are you making any "system level" adjustments based on what is on the RTA?

I would be scared to do that during a show.

The dual transfer function (when used properly-most people DO NOT use it properly), is much more immune to "other sounds".  An RTA will respond to any sound, a truck going by for example, that is not part of the actual sound coming out of the loudspeakers.

If the ONLY thing you are interested is the phase response-then yes, an mic will show you the differences.

HOWEVER- you should ALSO be concerned with the AMPLITUDE response of the two speakers are you are looking at.

So you need a flat response mic in order to show that.

Pretty much any "measurement mic"-including the Behringer, should be just fine at any freq you are trying to "align the phase". 

I would assume you are not trying to "align the phase" at 12KHz-because that is a waste of time.  If you move the mic a little bit , it will be all over the place.

But at lower freq (which is what I am assuming you are talking about), a cheap measurement mic will work just fine and give you the information you are looking for.

The tool you use depends on what job you are doing.  I don't see many people taking the BK4007s out to bar gigs or any case where it is likely to be damaged.
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Ivan Beaver
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Eugen Jeličić

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Re: Suggestions for SMAART measurement mic.
« Reply #13 on: January 29, 2017, 12:27:22 pm »

During the show, I would agree that in many cases an RTA is the best tool-but what are you actually doing with that tool?  Are you making any "system level" adjustments based on what is on the RTA?

I would be scared to do that during a show.

The dual transfer function (when used properly-most people DO NOT use it properly), is much more immune to "other sounds".  An RTA will respond to any sound, a truck going by for example, that is not part of the actual sound coming out of the loudspeakers.

If the ONLY thing you are interested is the phase response-then yes, an mic will show you the differences.

HOWEVER- you should ALSO be concerned with the AMPLITUDE response of the two speakers are you are looking at.

So you need a flat response mic in order to show that.

Pretty much any "measurement mic"-including the Behringer, should be just fine at any freq you are trying to "align the phase". 

I would assume you are not trying to "align the phase" at 12KHz-because that is a waste of time.  If you move the mic a little bit , it will be all over the place.

But at lower freq (which is what I am assuming you are talking about), a cheap measurement mic will work just fine and give you the information you are looking for.

The tool you use depends on what job you are doing.  I don't see many people taking the BK4007s out to bar gigs or any case where it is likely to be damaged.

No, usually not. But just like in the studio you can't have a 100% correct prediction of how things will sum together while you are eq-ing them channel by channel. So even if none of the instruments had any kind of 100-300hz ring or mud, that doesn't mean that in the overall mix some unexpected things might show up there. So if any kind of a "ring" shows up in the lowmids during the show, the SMAART RTA (especially with the slow spectrograph) tends to be usefull for things like this.

I am able to detect the problematic frequency by ear, relatively precise. But when you take a look at the nice big RTA it really helps you to put some things into better perspective. Helping you to touch up some of the channel eq-s a bit more or even the main mix eq if you want to generally rebalance the mix a bit.

Together with that, in case of a monitor feedback i usually know which monitor it came from since i keep looking at the stage and tracking what is the band doing. But if you had the smaart spectrograph turned on. You take a look at it and find a nice red line from a few seconds ago.
Then you can open the monitor EQ and eliminate a few dB from the problematic frequency.


2. Talking about the dual transfer function i will research a bit more about it and them possibly ask some quiestions.

3. Of course not, with the yamaha system that i run in a local club quiet much every weekend, the top boxes do combfilter but i know that it's not possible to solve that with a phase response graph since it would only work for one spot.
However i was going to try aligning the subs with the top boxes in the crossover area. (80-120hz)
I run the system crossed over at 110hz with a 24dB/octave BW cut.

4. True. The mic i need is mostly for "bar" gigs.


EDIT: What did you mean with "i should also be concerned with the amplitude response of the speakers that i'm looking at ?
If i'm aligning a dual 18 with the 2x15+1.5 top box, the levels that the sub is going to be running at compared to the top box is going to be my choice based on the type of music i'm mixing?
« Last Edit: January 29, 2017, 12:30:28 pm by Eugen Jeličić »
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Mac Kerr

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Re: Suggestions for SMAART measurement mic.
« Reply #14 on: January 29, 2017, 12:36:09 pm »

I am able to detect the problematic frequency by ear, relatively precise. But when you take a look at the nice big RTA it really helps you to put some things into better perspective. Helping you to touch up some of the channel eq-s a bit more or even the main mix eq if you want to generally rebalance the mix a bit.

Together with that, in case of a monitor feedback i usually know which monitor it came from since i keep looking at the stage and tracking what is the band doing. But if you had the smaart spectrograph turned on. You take a look at it and find a nice red line from a few seconds ago.
Then you can open the monitor EQ and eliminate a few dB from the problematic frequency.

Ivan has said it pretty well, but the quote above is the only thing you should be using an RTA for. Do not use it for guidance on whether or not you have too much of some frequency in your mix, that is what your ears are for. Use it to identify what that sound you are hearing is.

For tuning a PA you really need to learn about using the dual FFT capability of Smaart or any of the other FFT based analysis systems. Using an RTA makes you think you can fix an architectural problem with eq. You can't. Learn about Smaart, take the class, it is expensive, but it is worth it to find out all the things you don't know and have been doing wrong.

It doesn't matter what measurement mic you use.

Mac
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Eugen Jeličić

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Re: Suggestions for SMAART measurement mic.
« Reply #15 on: January 29, 2017, 12:49:36 pm »

Ivan has said it pretty well, but the quote above is the only thing you should be using an RTA for. Do not use it for guidance on whether or not you have too much of some frequency in your mix, that is what your ears are for. Use it to identify what that sound you are hearing is.

For tuning a PA you really need to learn about using the dual FFT capability of Smaart or any of the other FFT based analysis systems. Using an RTA makes you think you can fix an architectural problem with eq. You can't. Learn about Smaart, take the class, it is expensive, but it is worth it to find out all the things you don't know and have been doing wrong.

It doesn't matter what measurement mic you use.

Mac

Of course. I only look at the RTA after i hear a problem. Never to check if there are any problems that i don't hear. That doesn't make any sense.

I will get some literature / videos on that subject. That's one of the reasons i wanted a cheap measurement mic. It won't mean so much to me to improve my live mixes but i want to learn using smaart in depth.
I will first do a lot of reading and then go practice in the club i work in.
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Ivan Beaver

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Re: Suggestions for SMAART measurement mic.
« Reply #16 on: January 29, 2017, 04:19:53 pm »


2. Talking about the dual transfer function i will research a bit more about it and them possibly ask some quiestions.


You MUST use the dual transfer function when looking at the phase response anyway.  An RTA will NOT show you phase.

So while using the transfer function to look at phase-all you have to do is to look at the other screen-it is the freq response.
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Dave Garoutte

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Re: Suggestions for SMAART measurement mic.
« Reply #17 on: January 30, 2017, 07:59:34 pm »

I took the SMAART class recently, and the instructor showed us that the primary difference between the $100 mic and the $1k mic it the flatitude (yeah I know it's not a word) above 10khz. 
The more you pay, the higher the flatness goes.
His point was that even the cheap mics are flat in the range that is the most important.
The critical frequencies for sub alignment are at the crossover point; in the 80-200hz range.
He also noted that when someone knocks over your $100 mic, you don't have a heart attack.
Rational acoustics sells both cheap and expensive mics.
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Ivan Beaver

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Re: Suggestions for SMAART measurement mic.
« Reply #18 on: January 30, 2017, 09:03:52 pm »

I took the SMAART class recently, and the instructor showed us that the primary difference between the $100 mic and the $1k mic it the flatitude (yeah I know it's not a word) above 10khz. 
The more you pay, the higher the flatness goes.
His point was that even the cheap mics are flat in the range that is the most important.
The critical frequencies for sub alignment are at the crossover point; in the 80-200hz range.
He also noted that when someone knocks over your $100 mic, you don't have a heart attack.
Rational acoustics sells both cheap and expensive mics.

That is exactly why I keep the good mics for in shop usage and take the "throw aways" out when there might be any damage.

In a stadium setting there is no use in even worrying about anything above 10Khz.  You simply "aren't getting there" 800' away.
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Mark McFarlane

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Re: Suggestions for SMAART measurement mic.
« Reply #19 on: March 03, 2017, 12:17:32 am »

Another vote that the Behringer mic is good enough.   I have a calibrated Audix mic and a few Behringers.   

I 'hack calibrated' my two ECM800 Behringer mics against the Audix for fun, i.e. I stuck them in exactly the same position in front of a studio monitor and created a correction curve to make them match the calibrated Audix. Took about 20 minutes per mic. The differences between the Calibrated Audix and one ECM8000s were within +/- 1db above 100 Hz, and +/- 2dB on the second ECM8000.  Both ECM's needed larger corrections below 100Hz (up to 3dB and 6dB at 20Hz for the two mics). 

Even without the correction, performing a phase alignment of subs would be good enough with any of the uncorrected mics. With the tops on poles over the subs, standing up then sitting down would probably cause more phase misalignment than the cheap measurement mic.  With center clustered subs: moving left or right one seat would introduce more phase misalignment than the cheap mics.

The ECM8000s, along with your brain and ears, are good enough for your intended uses.

And yes, do treat your control room :)
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Mark McFarlane
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