microphone calibration by comparison - Home Theater Forum and Systems - HomeTheaterShack.com

Old 09-24-14, 03:02 AM Thread Starter
Shackster

Join Date: May 2012
Posts: 36
microphone calibration by comparison

it's probably a stupid question :
suppose i have a calibrate micro M1 and a non calibrate one M2
using M1 i take a measure (loading M1 file in calibration space) =>A1
using M2 i take a measure in the same condition ( unloading M1 file of course) =>A2
is the export measure of (A2-A1) represent the M2 calibration file ?
if not could you explain me while
thanks
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Old 09-24-14, 06:06 AM Thread Starter
Shackster

Join Date: May 2012
Posts: 36
Re: microphone calibration by comparison

i answser to myself
http://johnr.hifizine.com/2014/09/ho...ibration-file/ seems to anwser yes to my question but i don't understand why he does not use the A-B function available in REW (allSPL/Controls/trace arithmetic/generate then export measurement as text
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Old 09-24-14, 02:13 PM
REW Author

John

Join Date: Apr 2006
Location: UK
Posts: 6,301
Re: microphone calibration by comparison

Trace arithmetic takes into account both magnitude and phase, it could be used for that but you would need to ensure the two measurements had the same time alignment.
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Old 09-26-14, 05:29 AM
New Member

Join Date: May 2014
Posts: 3
Re: microphone calibration by comparison

As John said , you need to measure both at the same time.

Given the 2 spectrum measurements ( Sr - for reference and Sc - for the mic being calibrated ) a transfer function Src/Scc ( cross spectrum divided by auto spectrum of the signals) you give a transfer function in frequency domain that clones the reference mic in gain and phase.

Thare are also practical reasons of how close you can get the mics , and avoid placing the mics in nulls of frequency response in the room ( poor S/N ratio )
Toledo is offline
Old 09-26-14, 07:28 AM Thread Starter
Shackster

Join Date: May 2012
Posts: 36
Re: microphone calibration by comparison

ok but i can't measure with both micro in the same time because REW have only one input.
I try the method in the url i write above and it's seems to be good (but it does not take phase in account)
xxxx5 is offline
Old 09-27-14, 08:39 PM
New Member

Join Date: May 2014
Posts: 3
Re: microphone calibration by comparison

Look for Mathaudio . They have a plugin that does exactly what you want . Can`t post the link here because i`m new in the forum , spam prevention won`t let me .
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