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Sound values dB rms conversion to dB 0-peak

Started by Donatas911 July 2, 2014
Good day for everyone,

A question:

How to convert a sound pressure level value in dB rms to the level in dB 0
to Peak value (having a values reference 1 micro Pascal)? As I recognized
the relation for amplitude rms x 0.707 is valid for voltage values but that
is different.

D.

	 

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On Wed, 02 Jul 2014 19:13:48 -0500, "Donatas911"
<100629@dsprelated> wrote:

>Good day for everyone, > >A question: > >How to convert a sound pressure level value in dB rms to the level in dB 0 >to Peak value (having a values reference 1 micro Pascal)? As I recognized >the relation for amplitude rms x 0.707 is valid for voltage values but that >is different.
I'd be curious where you are going with this. It is not possible to convert between RMS and peak values in the general case, only in the case where you know the waveform shape. If you know that you have a sinusoid (RMS = 0.707 peak) then you can always convert dB back to volts, apply your factor, then convert back to dB. When you do that, you'll notice that it's the same as finding the "dB value" of the factor alone and adding or subtracting it from the RMS dB. Best regards, Bob Masta DAQARTA v7.60 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusiq generator Science with your sound card!
On 03.07.14 02.13, Donatas911 wrote:
> How to convert a sound pressure level value in dB rms to the level in dB 0 > to Peak value (having a values reference 1 micro Pascal)? As I recognized > the relation for amplitude rms x 0.707 is valid for voltage values but that > is different.
You are looking for the crest factor. It depends on the waveform. sqrt(.5) = 0.707 is the crest factor of sinus waveform. Other waveforms have other crest factors. But you man convert it to dB as well as any other amplitude factor. 0.707 = -3dB. Marcel
Thanks.

I'm working with underwtare noise research. There are plenty of different
metrics used to describe a noise levels so there is a need to convert
between a rms and 0-P or P-P metrics.	 

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I think a "ideal" noise, with a gauss distribution, would have to have
an infinite pp if it is long enough.

However, in technical systems one normally clips a something like
3 x standard_deviation without loosing much.
This would set the crest factor to 1/3.

Andre


On 04.07.2014 07:47, Donatas911 wrote:
> Thanks. > > I'm working with underwtare noise research. There are plenty of different > metrics used to describe a noise levels so there is a need to convert > between a rms and 0-P or P-P metrics. > > _____________________________ > Posted through www.DSPRelated.com >