13 Multichannel Audio

# Multichannel Audio

So far, in terms of sound production, we've explored triggering synths
and recorded sounds via the fns `play`, `synth` and `sample`. These have
then generated audio which has played through our stereo speaker
system. However, many computers also have the ability to input sound,
perhaps through a microphone, in addition to the ability to send sound
out to more than two speakers. Often, this capability is made possible
through the use of an external sound card - these are available for all
platforms. In this section of the tutorial we'll take a look at how we
can take advantage of these external sound cards and effortlessly work
with multiple channels of audio in and out of Sonic Pi.
