Statistical analysis of multiple REW measurements - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 05-05-13, 06:40 AM
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Wayne Myers

Join Date: Jun 2012
Location: Lincoln, NE
Posts: 4,609
Re: Statistical analysis of multiple REW measurements

Quote:
jamin wrote: View Post
RMS of the Pressure works out to averaging the intensity and is the method used for spatial averaging. As noted, this method gives less weight to lower measures.

Imagine 4 measurements with one of them 20 dB down from the other 3. Straight averaging of the dB would yield a measure -5 dB below the 3 overlays. An RMS, read as intensity average, yields a decrease of only ~-1.23 dB.

The flip side is to imagine 1 of the 4 measures being say 6dB above the other 3. With RMS this leads to an increase of ~2.4 dB whereas the straight average in dB yields an increase of 1.5 dB.

I tend to come down on the side of the established RMS calculation.

IMHO, FWIW, etc.
I think I understand what you are saying. In plainspeak hearing terms, it is like saying the 1 louder measurement "stands out" and should be given more weight, while the one softer measurement is masked and gets little weighting, using the RMS of Pressure calculatinon (avg of Intensity). Much like when one looks at a frequency response curve, a little bump in the curve can be easily heard, while a little notch int he curve (or even a fairly deep one if narrow) will go unnoticed. Is that what you mean? Makes more sense looking at it that way.

Thanks for the explanation. I change my vote.
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Old 05-05-13, 06:59 AM Thread Starter
Shackster
Mark

Join Date: Feb 2013
Location: UK
Posts: 13
My System
Re: Statistical analysis of multiple REW measurements

Quote:
RMS of the Pressure works out to averaging the intensity
I'm not a 100% convinced as this will weight the measurements towards those with less attenuation of the AT fabric (for multiple measurements of one fabric)? I need to get more results and see what they are. I'm taking a break from adding Soundbloc plasterboard to one of party walls so I haven't got time to do it just yet but I think my arms and back will demand a take a break from hard labour soon
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Old 05-05-13, 08:20 AM
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Wayne Myers

Join Date: Jun 2012
Location: Lincoln, NE
Posts: 4,609
Re: Statistical analysis of multiple REW measurements

Ah, yes, good old hard labor. The things we do.....

When you get back to your measurements, what you have posted so far only goes up to several hundred Hz, attenuation is likely to be higher at high frequencies.
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