BlueCat thingy won't help. Yes, you can load an instrument in it but how you'll feed audio in this instrument if it hasn't audio input? It "understands" MIDI only, there is no any input for audio in it.

 

Sometimes if you grovel and beg on the developer forum, they add it for you. I wish this was a universal VST feature on every synth and effect, being able to route external audio somewhere in their signal path...

Off the top of my mind, the Arturia Moog Modular could be used to do really great things with external audio.

 

The full code could be reversed, at least theoretically but it most certainly would be more efficient to rewrite the whole plugin.

It might even be possible to build an external audio input for plugins that don't have one. You would have to find the memory address of the generated audio stream and create a different stream that writes to the same address and overwrites the synths audio stream, but i wouldn't want to spend my time trying to achieve it. I rather would suggest to use a different synth that supports it.

Most of the time the effect or filter sections are not worth it anyways, with a few exceptions.. at least in my opinion.. and the synths that have good ones do provide a fx version a lot of the time.

 

but, some or not.

 

wow! thanks man! i did not expect a concise answer like that. thank you

 

List of the Ones I know :
Synthmaster 2
Surge
Cherry Audio Voltage

 

Also

Korg MS-20
Arturia Minimoog (I think)
G-Force Imposcar