This thing has some really cool sounding music, but would you believe I've never actually even heard one, or seen one in reality before! In fact, I don't think I knew anything about it until this forum came along. x3 It has some pretty amazing sound capabilities, though. I wonder if there's a tracker to simulate it~?
I'd say that ZX Spectrum's soundchip (AY series) isn't really similar to the C64 SID. It provides 3 voices with frequency and envelope controlls, each voice being doubled by a noise generator also featuring an envelope. No filters, nothing fancy. Tracker software provides aditional modulation, like arpegios and envelope retriggering. http://en.wikipedia.org/wiki/AY-3-8912
SoundTracker for the ZX Spectrum:
A lot of ZX Spectrum clones don't feature the AY chip (wich is a later adition on the ZX itself), leaving the user with just a buzzer - 1bit sound. However, interesting results can come up from that as well, as it can be heard in Chronos - a classic game:
Software using buzzer: Wham!(2 tracks "poliphony), ZX-7 (imitates 8 voice poliphony!), Opus1 (probably the best sound).
There were also various extension interfaces available, such as Currah MicroSpeech (speech synthesis) or the SpecDrum (sampled percussion). Here's a track from ZX Spectrum Orchestra wich features MicroSpeech:
I said that SID is similar to the ZX chip because the way I've heard it in ZX music it sounded like SID(probably identical waveforms), unlike the chip on the NES which is based on the square wave type.
I doubt that. Editable parameters in SoundTracker for each "sample" (that's what it's called, actually it's a voice preset / tracker instrument definition) are just envelopes for wave & noise (step-based envelope, not ADSR) and pitch (also for each step). I'd say there are some PWM capabilities too, judging by hearing (I haven't been digging too deep, though I can hear some nice "fizzy" waves ), but that's pretty much it. No waveform selection (sounds like squarewave to me). Arpegios/retriggering are partially pre-set (called "ornaments").
Now, SID filter sounds quite discrete in the original hardware environment, not to mention that a lot of chiptune music uses fast arpegio techniques (1/32, 1/64, or faster - it's a "signature" sound for chiptunes). Therefore the resemblance