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

Where I was raised (south pole of Mars, IIRC), absent any other reference, a "ratio" of 1:1 was always 0 db. But I can adapt. ChucK is like a box of chocolates -- you never know what you're going to get. - Rob

----- "Perry R Cook" wrote:

...

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.

PRC

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