new engine: Octode 2k16

so nice... the tune is great (as usual), it doesn't really sounds like regular 1bit music. Well done. For the fuse version I don't really understand what is wrong, except maybe it sounds less "full". Did you use some postproduction effects on the zx48 version on soundcloud?

Thx guys Barely any post-production, just a tad of added bass (+3 db). For me, fuse adds quite a bit of distortion when 7 or 8 channels are active. There is some distortion on hw, but it's less intrusive and more irregular. Fuse makes the bass sound like a YM buzzer in saw mode, on hw it's more of a muddy, fuzzy kind of sound. Oddly enough with fluidcore it's the other way around - fuse sounds rather clean, whereas hw has random clicks and pops and a nasty buzz when going into higher volume levels. In any case it's surprising, since normally fuse's beeper emulation is quite excellent. Guess I should eventually talk to fred about this, but I first want to investigate a bit more myself.

Also, the more important question for me is what causes these distortions in the first place. At the moment, I have two theories.
1) Full speaker expansion is reached before the sound loop is completed, hence the sound is clipping. However, if that was the case, pulse-interleaving engines should also have that problem, but generally they don't exhibit these symptoms.
2) Speaker cone response is non-linear, ie the cone starts to expand slowly and then gradually moves faster. I think this is more likely, so I'll be looking into this.

Edit: I think I've figured it out. Third, much more logical hypothesis:

3) The problem is that I'm only looking at speaker cone expansion, but not at contraction. Now, when a string of several high volume samples is played, the speaker cone has no time contract inbetween, hence the volume starts to ramp up. For pulse-interleaving engines this is rarely a problem because there, on and off states are alternating most of the time, preventing volume ramping. But fluidcore, wtfx, and Octode 2k16 only toggle the state once or twice within a sound loop frame, so I need to add another mechanism to prevent volume ramping.

This also gives me another idea - perhaps the volume ramping phenomenon can actually used on purpose to simulate the AY buzzer effect. Hmmm... exiting days for beeper.