This post focuses on the process of recording your MIDI sequenced tracks to audio tracks.
Bouncing is the process of recording one or more tracks of audio to one or more other tracks of audio. I think the term comes from the days when tape channels were limited and multiple tracks of audio had to be condensed to a mono track or stereo pair. Why is it called ‘bouncing’, specifically? Because ‘rerecording’ is boring and ‘flootzing’ made the engineer crack up, reducing the efficiency of the session.
These days we have all the audio tracks we could ever need in our computers. But bouncing is still quite useful for many reasons. One of the best reasons is the preservation of sequenced instruments such as synths or samplers, especially virtual instruments. The fact of the matter is that MIDI is completely dependent on the MIDI instrument to produce the sound. If your precious vintage synth were to kick the bucket or if you loose the dongle for your favorite virtual instrument, you won’t be able to play back the track. Bouncing to audio has two advantages: a) if the instrument is a virtual instrument, you’ll save the CPU usage imposed by real-time playback b) should something ever happen to your instrument, you can still work with the audio track.
It doesn’t make sense to get rid of the MIDI altogether. Obviously the MIDI part is easily editable while the audio track isn’t. Therefore, only bounce the audio once you’re pretty sure the MIDI sequence is in its final or close-to-final form.
Most modern sequencer/multitrack software packages offer flexible internal routing to allow a virtual instrument’s audio track to be routed into the input of a record-armed audio track. My sequencer of choice, Cubase, finally supports this sort of routing with the latest release, version 4.1. I’ve been waiting for that patch for years, I’ve gotta say. Users of earlier Cubase incarnations will have to do what I did for years: take a digital out from your interface, loop it back to the digital in of your interface, and route the virtual instrument out the digital out, recording an audio track from the digital in. Don’t monitor that input or you may get some NASTY digital feedback (probably not – but digital feedback is awful so don’t do it anyway!) Refer to your DAW’s documentation or various forums on the ‘net to find out exactly how yours works. If your instrument is simply a hardware device, just take the audio outputs of the instrument into your audio interface and record it back in as you playback the sequence (using the digital I/O if it’s available).
You’ll want to have your buffer size rather high to avoid CPU hiccups. Also, name your audio tracks before you hit record so that the file names are named appropriately.
Each of these tracks will have to be recorded in real-time, although if you have a lot of I/O and a nice machine you can probably get away with bouncing multiple tracks at once. Make sure to listen to each bounce to ensure that no hiccups or other weirdness occurs because if they do, they’ll be on your audio track. Obviously, it’s best to leave your computer alone while tracking these things. Don’t play Doom in the background or anything, unless you’re Rewired into Doom’s audio engine (that’s a joke, folks).
Once I’m done with the bounces, I usually drag my audio tracks into line with the other audio tracks, then drag my MIDI tracks down to the bottom (muting them and disabling the virtual instrument to save CPU).
If you find you have to edit the part, re-enable the MIDI track and instrument, edit, and record over the previous audio bounce.