Перехват звука (ALSA)

man rec 

       Some systems provide more than one type of (SoX-compatible) audio driver, e.g. ALSA & OSS, or SUNAU  &  AO.   Systems  can
       also  have  more than one audio device (a.k.a. `sound card').  If more than one audio driver has been built-in to SoX, and
       the default selected by SoX when recording or playing is not the one that is  wanted,  then  the  AUDIODRIVER  environment
       variable can be used to override the default.  For example (on many systems):
          set AUDIODRIVER=oss
          play ...
       The AUDIODEV environment variable can be used to override the default audio device, e.g.
          set AUDIODEV=/dev/dsp2
          play ...
          sox ... -t oss
       or
          set AUDIODEV=hw:soundwave,1,2
          play ...
          sox ... -t alsa
       Note  that  the  way  of  setting  environment  variables  varies  from system to system - for some specific examples, see
       `SOX_OPTS' below.
       When playing a file with a sample rate that is not supported by the audio output device, SoX will automatically invoke the
       rate  effect to perform the necessary sample rate conversion.  For compatibility with old hardware, the default rate qual‐
       ity level is set to `low'. This can be changed by explicitly specifying the rate effect with a  different  quality  level,
       e.g.
          play ... rate -m
       or by using the --play-rate-arg option (see below).