If you have an old digital polysynth that you no longer use because you’re unhappy with the sounds, here’s a way to bring it back to life with some analog attitude.
If you own a monosynth that includes an external-audio input jack, you can use its filter and amp to process the output of the other synth. The term paraphonic is used to describe this scenario, where a polyphonic instrument is running all of its voices through a single VCF and VCA. Modern analog monosynths with an external-audio input include Korg Monologue, the Arturia Minibrute and Microbrute, the Novation Bass Station 2, and all of the recent synths from Moog Music.
To get started, plug the MIDI Out from your monophonic synth into the MIDI In of the older polyphonic synth. Next, plug the audio output of the polysynth into the external-audio input on your mono synth. Now you’re in business.
If you want filter the digital synth while it plays a sequence, send the same MIDI data to both synths, with the audio connections described above in place. Sometimes, it is useful to remove all but the lowest notes from the track that is controlling the monosynth: In certain cases, this will prevent the extra polyphony from potentially “confusing” the monosynth.
As I described in my article “The Integrated Studio” last month (available at emusician.com), you can use also this method to process audio from your software synths and other virtual instruments if you have an audio interface with multiple outputs. Simply route the audio from your softsynths to one of your interface’s spare audio outputs, then connect the corresponding output jack to the input of your monosynth. From there, follow the process above.