[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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