Hi,

greeting all!

I come up with a troubling problem these days.

I work with somd Sound Designers. They make some game sample datas to use for me.

Unfortunately, the unit is always so different.

eg: in fmod, for each sound use volume from 0.0~1.0; freq maybe 16000hz for a channel.

but the sample date Designer offer me is like this: vol in DB unit from -96db ~ 0db, freq use "pitch" from -3.0 ~ 3.0.

what’s worse, the relation between the 2 ways is not "linearity".

then how can I calculate the correct value of the sample datas to use?

Thank you very much for help.

- mecgouki asked 10 years ago

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If you are just getting data from them outside of fmod, just use db to linear conversion formula

Ie linear = 10^(db/10)

Pitch could be converted as

float val = basefrequency_of_sound * (2 ^ pitch);

basefrequency_of_sound would be the recorded rate of the sound ie 44khz.

- Brett Paterson answered 10 years ago

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That’s the formula for signal power, but I’ve always seen linear volumes expressed as voltage in code (+6 dB is about x2 multiplier):

linear = 10^(db/20)

The frequency formula you gave works when "pitch 1.0" means one octave. If they’re using semitones, and "pitch 12.0" means one octave, the formula becomes:

float val = basefrequency_of_sound * (2 ^ pitch/12);

- sgugler answered 10 years ago

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