On 13/02/25 16:39, Doug Lee wrote:
I find that these sound similar except that, at low frequencies, the second sounds twice as fast as the
first; but I was expecting the second to involve an audible vibrato-type effect instead of an amplitude
effect:
play "|sox -n -p synth 0 sin 440 vol .4" synth 60 sin am 1-500
play "|sox -n -p synth 0 sin 440 vol .4" synth 60 sin fm 1-500
^^
I suspect I misunderstand the nature of fmod here. I thought the amplitude of the second wave would alter
the frequency of the first.
The only difference between amod and fmod is tha amod takes the synthed
wave as being from 0 to 1
and fmod takes it as being from -1 to +1. That's all.
"fmod" is not a frequency modulator; it is a phase modulator that
changes the offset
into a delayed version of the input, the same as the Yamaha DX7 is not
FM but is PM.
The result is kinda similar and it does change the frequency of the signal
but only as a function of the slope of the modulating wave.
SoX doesn't have a true frequency modulator (except for "bend") but may yet.
M
_______________________________________________
Sox-users mailing list
Sox-users@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/sox-users
