Hello,
thanks guys.
Well, I use only ZX SoundTracker 1.1 on Spectrum, it has no MIDI and it has only 3 channels (uses only one AY chip).
What I do is making "one half" of the song first = 3 channels. Then I make "the second part" of the song.
Both on ZX Spectrum's Soundtracker.
Then I merge both parts in Vortex-Tracker on PC (it has an ability to mix two traditional 3ch ZX songs).
I export it back to ZX Spectrum and entire TurboSound music will play from any ZX with two AY chips.
The drums and synth improvisations have been made totally live, without MIDI or anything additional (except our hands, haha).
We played the song something like 7 times and Larek was recording audio and video. Then we have chosen the best audio version (mixed mostly by Pinokio) and Larek was making the video part with all the available video material.