Difference between revisions of "RMS"

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(Created page with '== What is RMS == The Root Mean Square is a way to express the actual sound pressure of a piece of audio. It is a sort of averaging method that suits audio well. == Calculating …')
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Revision as of 17:26, 25 March 2010

What is RMS

The Root Mean Square is a way to express the actual sound pressure of a piece of audio. It is a sort of averaging method that suits audio well.

Calculating and displaying RMS

  1. Select a 50 ms piece of audio (uncertain here, please confirm)
  2. take each sample and multiply it by itself
  3. take all those resulting values and add them
  4. divide that by the amount of samples added (let's call that value "x")
  5. x = powf(x, 1/6);
  6. silence is now 0.00, and the max (0 dB) point is 1.00 (but higher vales CAN occur in Buzz!)
  7. scale this to the size of the graphics, leaving some space for the headroom (e.g. +6 dB)

This will display the RMS value scaled onto the x^3 curve as suggested by JoaCHIP's audio gui design page. If you want a linear representation, simply replace step 5 with x=sqrt(x).