Regarding differences between YM and AY

[XiA]

I’ve been reading the datasheets on the AY-3-8912 and the YM2149, and the only difference I can see is that while the AY chips always have 16 volume levels, the YM has 32 – but only for the hardware envelopes:

http://sc68.atari.org/developers_technicals.html

Letting the user choose AY or YM chip is possibly a good idea then, given that there seems to be specific sounds Arkos Tracker 2 can’t seem to create currently (v2.0.0a2):

https://youtu.be/ughFB9_ufqI?t=738

It’s certainly a bit of extra work, and I don’t know how important supporting the ST is for you.

[Targhan]

There are two differences, to my knowledge:
– As you pointed out, the YM has 32 envelopes, only used for hardware envelopes.
– The volume output are also different from the AY (some called it “steeper”).

I will eventually emulate these, however the difference is subtle and I’m not sure this will make a big difference. It wasn’t on my priority list because no ST sceners were interested in AT2… yet :).

As for the sound of the Lightning demo, it is already possible to do it. Simply use the “hardware to software” sound (sound type number 4) and use the “A” envelope. There is still indeed a small difference, but I don’t know if it is because of the emulation (mine or the one used for the video), or indeed because the 32-step hardware envelope.

[Author]

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