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   rec.audio.tech      Theoretical, factual, and DIY topics in      41,683 messages   

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   Message 40,142 of 41,683   
   glen herrmannsfeldt to dpierce@cartchunk.org   
   Re: dBFS   
   21 Nov 10 07:06:07   
   
   XPost: rec.audio.pro, comp.dsp   
   From: gah@ugcs.caltech.edu   
      
   In comp.dsp Dick Pierce  wrote:   
      
   (snip, I wrote)   
      
   >> In EE, RMS can mean different things.   
      
   > Not in any "EE" I ever encountered. It means one thing:   
      
   >    sqrt(sum(X1^2 + X2^2 ... +Xn^2) / n)   
      
   It used to be, for DVMs, that was called True RMS.  When   
   they figured out how to actually do that electrically.   
      
   Maybe they all do now, so it isn't a problem anymore,   
   but it didn't used by be that way.  Also, it isn't   
   for the peak-to-peak reading VTVM, normally calibrated   
   with an RMS (assuming sine) scale.   
      
   > Now, what's partly at the root of this discussion is that   
   > if we were to scale our system such that we called   
      
   >    max(abs(X1, X1 ...Xn))   
      
   > "full scale," what is the ratio of the RMS value of that   
   > set to the full scale value of that set.   
      
   -- glen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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