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Comparing ARMSID and real 6581 SID

I
've set up a YouTube channel for posting my music, mostly to give myself an incentive to keep writing and hopefully improve those skills.

I recently posted a version of this eastern-sounding piece rendered by the notation software. An exercise in using the pentatonic minor for that eastern flavour.

I've now made recordings of the C64 playing the piece. First of all I made a 3-voice version (not yet posted) and then an 8-voice version using multi-tracking.

That's the first version you hear in this video, played on my 'bionic 64' which is fitted with an ARMSID.

Curious about how this would compare with the same music played by a real 6581 SID, I did the same recording using an all-original 64 and made a video with one recording after the other. My observations are below but judge for yourself.


In the 'pure' tones it's hard to hear a difference. But there is definitely a difference when there are many voices playing together and using pulse-wave modulation (varying the duty-cycle). These more complex sounds are all a little cleaner with the ARMSID and sound grittier with the real one.

I think this is consistent with the difference between the 6581 or 8580. I didn't realise this before now but the ARMSID auto-detects and decides which of the two SIDs to emulate. To be a fair comparison here I need to check that it is emulating the 6581 as it should be.

I do note a very strange glitch in the middle of D in the ARMSID version where a couple of notes mysteriously end early. I can't see anything unusual about those notes and the other 64 plays them (running the same program) without the same problem.
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