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ColEm Emulator for Windows, Android, and Linux

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19 hours ago, GarageResearch said:

I think the problem there is that the voice is done via some PSG hack, since AY891x PSG does not provide sampled output capabilities. Such hacks are not emulated by ColEm at the moment.

FYI, the AY code from MAME supports it... You could check that out.

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29 minutes ago, bhall408 said:

FYI, the AY code from MAME supports it... You could check that out.

I have a policy of writing my own code. Having said that, it is more or less clear what is going on. The software stalls a PSG sound channel, then manipulates its volume in real-time, as if it were a DAC of sorts.

 

Since PSG emulation in ColEm works in terms of frequencies/volumes, rather than audio samples (letting you record PSG music into MIDI), simulating this pseudo "DAC" behavior is very messy. I do have it on the todo list, but the two or three games using this "feature" make it a low priority.

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13 minutes ago, GarageResearch said:

Since PSG emulation in ColEm works in terms of frequencies/volumes, rather than audio samples (letting you record PSG music into MIDI), simulating this pseudo "DAC" behavior is very messy. I do have it on the todo list, but the two or three games using this "feature" make it a low priority.

One nice side effect of using the frequencies is that (at least to me) the result sounds much nicer/"upscaled" to taking the more hardware faithful approach. Downside is lower compatibility (AY was also used on Vectrex, which had a bunch of original era games that made use of sampled sounds).

 

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3 hours ago, bhall408 said:

One nice side effect of using the frequencies is that (at least to me) the result sounds much nicer/"upscaled" to taking the more hardware faithful approach. Downside is lower compatibility (AY was also used on Vectrex, which had a bunch of original era games that made use of sampled sounds).

 

The DAC trick mentioned above is pretty much the only incompatibility, as far as AY891x is concerned. YM2608/YM2612 and other FM chips really require a sample-based approach.

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On 7/30/2020 at 7:56 PM, GarageResearch said:

I think the problem there is that the voice is done via some PSG hack, since AY891x PSG does not provide sampled output capabilities. Such hacks are not emulated by ColEm at the moment.

Oh ok no worries, thank you!! Love the emulator regardless!!  Thank you!!!

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