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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: Johnny Diaz on October 10, 2012, 04:48:38 PM

Title: Microphone Calibrator
Post by: Johnny Diaz on October 10, 2012, 04:48:38 PM
So what is everyone using to calibrate their microphones in Smaart when setting up the SPL feature.
Title: Re: Microphone Calibrator
Post by: Dave Jones on October 10, 2012, 06:17:11 PM
So what is everyone using to calibrate their microphones in Smaart when setting up the SPL feature.

In my case I use an Ebay Chinese special.

http://www.ebay.com/itm/New-Digital-Sound-Level-Meter-Calibrator-94-114dB-Class-I-1-Fit-1-1-2-Mic-/251080344475?pt=LH_DefaultDomain_0&hash=item3a758e039b (http://www.ebay.com/itm/New-Digital-Sound-Level-Meter-Calibrator-94-114dB-Class-I-1-Fit-1-1-2-Mic-/251080344475?pt=LH_DefaultDomain_0&hash=item3a758e039b)

I have a nearby University that has the "good acoustics test gear" so was able to test the Chinese calibrator. It was within 02.db. I have no doubt that it will probably shift but for my uses it's fine.

Dj
Title: Re: Microphone Calibrator
Post by: Arthur Skudra on October 11, 2012, 06:33:58 PM
So what is everyone using to calibrate their microphones in Smaart when setting up the SPL feature.
I'm currently using a B&K type 4231 calibrator that I found on eBay for $250!  The reason I got it so cheap was that the auction was mislabled and didn't mention anything about B&K, which usually jacks the price up considerably!  I guess I looked at the right time, and instantly recognized what it really was in the pictures!

Otherwise I've gotten other calibrators on eBay for cheap:  Simpson 890, Quest CA-22, Larson Davis CA250 which work really well and are my backups, maybe one of these days I might sell one or two of these.

Here's a few things to look for:
1.  If you need something super accurate and reliable, then look for a type 1 calibrator.  If being off by a fraction of a dB is ok for your work (in most cases with live sound reinforcement), then a type 2 calibrator is perfectly acceptable and worth the savings.
2.  Find one with both 94 and 114 dB SPL settings.  If you're doing loud concerts, you'll appreciate the 114 calibration level.  If you're doing a corporate gig, 94 should work well.  A 1KHz tone is pretty much standard so that you are calibrated regardless of the weighting chosen (A or C weighting), though some also have a 250 Hz tone.  For Smaart use the 1K tone.
3.  The fit around the tip of the mic must be airtight when you're calibrating.  So make sure you get an adapter that is properly sized for the mics you're using.  Some manufacturers provide such an adapter with their mic.  With some mics/calibrators, you may need to have an adapter custom made by someone who has a lathe in their shop.  Harry Brill makes them as well.


Title: Re: Microphone Calibrator
Post by: Timo Beckman on October 12, 2012, 06:22:22 AM
I'm using a delta-ohm type 1 callibrator . The costs where about 850 euro here in the netherlands . The B&K was the original choice but the run up to about 1500 ex VAT so that was a bit to much for me at that time .
I do calibrate each mic on each start of a measurement .
I did check if the level was accurate with SIM3 and the value i have to give a mic within the branches menu .
The level was off by about 0,14db if i remember correctly....meaning it's acurate enough to do the job
Title: Re: Microphone Calibrator
Post by: Johnny Diaz on October 12, 2012, 12:22:26 PM
How about the link below?  I don't need it to be precise within 1-2db is fine.

http://www.rationalacoustics.com/store/microphones/isemcon-sc-1.html
Title: Re: Microphone Calibrator
Post by: Ivan Beaver on October 13, 2012, 09:43:31 AM
Just to add to the other valuable comments-a calibrator is ONLY good at the freq of generation.

It does not "flatten out the response" or check or set for any deviations in response.

If there is a "hole" at the calibration freq"-then the whole thing will be off.

It only does level.

It is also a good idea to have your calibrator-calibrated from time to time.  That is-going back to a standard reference.

The best way is to send it back to the manufacturer or to a certified calibration house.

You can compare it to other calibrators-and if they all agree-then you are probably OK.

As the old saying goes  "A man with 1 meter is sure-A man with 2 meters is sure of nothing".
Title: Re: Microphone Calibrator
Post by: Timo Beckman on October 14, 2012, 06:50:12 AM
As the old saying goes  "A man with 1 meter is sure-A man with 2 meters is sure of nothing".

I wish there was a like button on this forum or if there is one i wish i coulld find it  8)
Title: Re: Microphone Calibrator
Post by: Dave Mason on April 19, 2015, 04:52:13 PM
Conventional SLMs with snouts are easy, provided you have a standard (somewhat expensive) calibrator and usually adapters for the 1" / 15/16" / 1/2" etc. snout.  Smartphones running SLM apps are hard, unless you have a plug-in snouted mic.  Otherwise AFAIK nobody sells  portable calibrators that work with smartphones.  Instead you probably need a sound booth or an outdoor setup for comparison with a calibrated SLM.
Title: Re: Microphone Calibrator
Post by: Timo Beckman on April 20, 2015, 10:43:46 AM
You might take a look at the ISEMcon SC1.
Title: Re: Microphone Calibrator
Post by: Hayden J. Nebus on April 21, 2015, 06:34:58 PM
You might take a look at the ISEMcon SC1.

We have an SC1. It's built very well and has been precise  thus  far.


Timo, how often should these be recalibrated?
Title: Re: Microphone Calibrator
Post by: Timo Beckman on April 23, 2015, 08:36:02 AM
Don't know  ???
That's a nice question for the Isemcon guy's. I'll have to get back to you for that or ask yourself.....
Title: Re: Microphone Calibrator
Post by: Timo Beckman on April 23, 2015, 05:24:39 PM
Don't know  ???
That's a nice question for the Isemcon guy's. I'll have to get back to you for that or ask yourself.....

I had to ask but every 1 or 2 years it's a good thing to recalibrate @Hayden