[chuck-users] dbtopow(), dbtorms(), powtodb(), powtorms() off by 100 db (Robert Poor)

Perry R Cook prc at CS.Princeton.EDU
Sun May 3 13:17:53 EDT 2009

dB just implies 20log_10.  A reference must be selected.

The most common are dBV (1 volt = 0dB), dBm (0dB = 1 milliwatt into
600 ohms), and dBSPL (watts relative to threshold of hearing at 0dB).

I suspect that the implementers of this were thinking about 
the approximate 96dB of 16 bit audio, and the +/-1.0 float 
recommended max range of STK.  Thus a range of 0.00001=0dB
to 1.0=100dB resulted.  Easy to change to any reference by
just subtracting/adding/multiplying/dividing by a constant.


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