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sfam − apply amplitude modulation to a soundfile |
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sfam [−t][−a][−r][−m MI][−A dB][−o output] soundfile |
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sfam applies amplitude modulation (or its variants, tremolo and ring modulation) to a soundfile. Amplitude modulation is implemented as |
( 1 + mi * cos(2*pi*f/sr*t) ) * inputData[t]
Ring modulation is implemented as
( mi * cos(2*pi*f/sr*t) ) * inputData[t]
In both cases, mi is restricted to values between 0 and 2.
Tremolo is implemented as
( ( sin( 2*pi*f*t/sr ) + 1.0 ) / 2.0 ) * inputData[t]
This preserves the sign of the input signal.
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sfam -a -f 40 -m 1.5 -A 72 -o out.wav inputSound.aiff applies amplitude modulation with a frequency of 40 Hz., a modulation index of 1.5, and an output level of 72 dB to the input sound inputSound.aiff and places the output in the file out.wav |
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−t |
Apply tremolo to the input sound. |
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−a |
Apply amplitude modulation to the input sound. |
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−r |
Apply ring modulation to the input sound. |
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−f n |
Frequency n (in Hertz) for amplitude or ring modulation. |
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−m n |
The "modulation index". n must be between 0-2. |
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−A n |
Desired output amplitude n given in decibels. |
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−o file |
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Place the output in file . |
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This program will only work with WAVE, AIFF, AIFC, and the old NeXT/Sun "snd" format soundfiles, that are 16-bit PCM encoded, with 1 or 2 channels. |
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Arun Chandra <arunc@evergreen.edu> sfam is free software. |