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Discussion Starter #1
Hi everyone, as a NPO we're experimenting multiamplification with an HT amplifier (Yamaha RX-V663) that provides a "measurement tool" for calibration (the well-known Ypao microphone).

Even if we obviously know that it's not the best method to obtain good results, what level of accuracy do you think it can have?

Thanks in advance to anyone that can/will help with constructive suggestions.
 

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When I used it (a little while back), YPAO was almost useless in the low end, exactly where REQ is most needed.
 

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Discussion Starter #4
Sorry for the misunderstanding (we haven't clearly stated the intent, obviously), but we do not want to use the Ypao FUNCTION - we will use software like REW of course - but only the tool (microphone).
 

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There is no way to gauge the accuracy of the YPAO mic without a frequency response plot of it generated by a lab. It will work fine if your only interest is acoustics measurements (such as ETC), but if you want accurate frequency response measurements, that requires a calibrated mic. Otherwise you have no way of knowing if you're seeing the frequency response of the speakers or the mic itself.

Regards,
Wayne
 

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Discussion Starter #6
Thanks for the infos.

Another question: is possible to calibrate it easily ?

To be more clear: if we use a (couple of ?) calibrated mic to measure some signals then compare to the same measured by the Ypao mic, is possible to obtain a calibration "by difference" ?

Thanks again for any hints/suggestions you can/will provide.
 

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There is a long mic shootout thread on AVS about this.

My personal experience is that most certainly the Denon/Marantz Audessey mic's and the Onkyo/Pioneer mics are suitable for use with REW, at least in the sub 100hz region.

I used both and got great results eq'ing multiple subs.

I now use the Dayton Audio Omnimic so can vouch for the accuracy of these mics.

I don't have direct experience with the Yamaha mic but I'd be willing to bet it will be great for this purpose too.

Hope this helps. Good luck.
 

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I've calibrated a couple hundred Yamaha receivers, among others. Not to sound harsh, but the ypao mic cali rarely gets the distance right, rarely gets the crossover right, and rarely gets the level right. Why would I trust it with the EQ? A Rat Shack spl meter (or even your phone) and a measuring tape will get you more accurate results.

That said, I WOULD prefer the YPAO calibration to no calibration at all.

As for your experiment, it is my understanding that YPAO and other mics that are included with receivers are calibrated to work with only their specific AVRs.
 

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Don't think because the reported physical distance appears wrong that it's actually incorrect. The "distance" is more accurately "timing" of the signal to/for each channel. There's a few things that can effect the delivery "time" of sound including room acoustic/environment variables and amp processing time. Example: In the case of a sub with an internal amp>> the distance reported by YAPO (or any other calibration app) may be different than the actual physical distance because of the additional processing time of the built in sub amp. It may only be a millisecond or two/three of additional time but those few milliseconds translated into "feet at the speed of sound" can easily equate to an adjustment of 1-2 (or whatever) feet to compensate for the additional processing time of the subs internal amp. Sound travels at 1.13 feet per millisecond so a sub with an internal amp with say, exactly 2ms processing time, YAPO may put that sub 2.26 feet further out than it's physical distance to compensate for the additional sub amp processing time. I read about this topic in a manufacturers white paper on room compensation a while back.
 

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Don't think because the reported physical distance appears wrong that it's actually incorrect. .......................................................... YAPO may put that sub 2.26 feet further out than it's physical distance to compensate for the additional sub amp processing time. I read about this topic in a manufacturers white paper on room compensation a while back.
You are correct in this statement. That does not change the fact that YPAO doesn't make correct/effective EQ in the bass, including the subwoofer.
 

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You are correct in this statement. That does not change the fact that YPAO doesn't make correct/effective EQ in the bass, including the subwoofer.
Absolutely. Subwoofer measured distance can vary from physical distance by several inches or feet. However, distance from mains and surrounds should always line up with physical distance as their wavelength is much smaller and should be based on the initial impulse response rather than measurements that involve reflections. YPAO rarely gets these measurements right. If they are off, even by a few inches, the result is a smear in imaging.
 
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