[Oktalyzer](http://www.vgmpf.com/Wiki/index.php?title=Oktalyzer) was a Tracker style program for Amiga, that allowed composing and playing music with 8 channels instead of the "hardware-natural" 4.

So far I learned it achieved that by splitting the 4 8-bit channels into 8 4-bit ones. But I still don't understand how it was done from 'mathematics' point of view - it doesn't seem like you can split a DAC index into two halves and have two waveforms of comparable volume overlaid.

One would range 0-16 in 1-bit increments and the other 0-256 in 16-bit increments, resulting in one being 16 times more quiet than the other. Or you could take every other bit, achieving 16-bit increments on both, but one would still be half as loud as the other, not having access to the most significant bit. How was it done in reality?