[Audio] Audio's properties?

Latelty i've been trying to messing around A.S and made a little piece of music, which later I tried to assemble. I transfered missing instruments to voicegroup I used so everything was ready. However when I played it via VBA it sounded kind off... odd. Generaly drums and gunshots. It felt like someone deleted some of their notes randomly. Looking at instrument's properties there were:
- 3 MultiSamples.
- 2 DirectSounds.
- 1 Noise.
- 1 Drum.

And here's my question: Does Pokemon Fire Red has some kind of limitation of used instrument kinds?
If yes, is it possible to baypass them?

five direct sounds can be tricked up to sixteen, but the more direct sounds in a track, the more noise. I recommend putting an ipatics mixer. The more multisamples the more friezes. two squares per track maximum (first and second) the first two will fail or two second. If I am not mistaken channel 1,2-square 3-wave 4-noise
https://www.pokecommunity.com/showpost.php?p=7559059&postcount=316