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Repose
Registered: Oct 2010
Posts: 225 |
Ultimate reverse engineering
This person took 32 chips of every revision, connected them to a custom clock source and ran them independently, to read out the OSC3/ENV3 of every combination, plus analog recordings. He wrote an emulator which recreates every register setting and measures all the variations within and between chips. Its an amazing amount of work. He also reverse engineered CIA's as well, as those are needed for "real sid" type tunes, which require emulating the entire machine for music playback.
https://www.youtube.com/watch?v=pePq68HaI7M
Emulating the SID the HARD way.
plgDavid
Here is one of the "torture test" tunes which require very accurate emulation of a specific model, it sounds amazing:
https://www.youtube.com/watch?v=BVevORuyQ_8
Jammer - Club Stylier
Club Stylier
Forever 2010 - #1 |
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iAN CooG
Registered: May 2002
Posts: 3193 |
Sounds correctly in
Sidplay/w 2.6 (ReSIDfp V0.0.2 Engine)
Sidplay 3 (ReSIDfp V2.4.0a Engine) (but at a bit lower volume)
VICE VSID (3.2 and 3.71 tested)
too bad doesn't sound correctly in ACID64 3.x+JsidDevice |
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Repose
Registered: Oct 2010
Posts: 225 |
Yes, I made the mistake of assuming that DeepSID was using the reSID engine.
DeepSID "WebSID Player" and VLC are the two which failed for me. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Quote:DeepSID "WebSID Player" and VLC are the two which failed for me.
Deepsid is really only "okish" for relatively "normal" tunes without samples or any other trickery. VLC uses a very old libplaysid iirc, like reSID from 20 years ago :) |
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Repose
Registered: Oct 2010
Posts: 225 |
I am using Sidplay 3 now, but its really really quiet. I'm wondering if I can compile this myself... |
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NoiseEHC
Registered: Feb 2005
Posts: 51 |
Just two fast little related questions:
What is considered the "best" SID emulation engine? Is it ReSIDfp?
I have seen "resonance fix" patched sidplay26w versions like a decade ago. Are those patches already merged into ReSIDfp mainline? Or were they pointless to begin with?
I ask these question because I will need something to play back sound in a sound editor for my player. Obviously either it should play on a real C64 or the best emulator. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Current reSID and reSIDfp are pretty much on par. The difference is mostly the way filter can be tweaked to your liking, and perhaps the defaults for them. Its mostly a matter of taste. All fixes have gone into both since Leandro is maintaining libresid(fp) |
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Grue
Registered: Dec 2001
Posts: 162 |
Think that resid is the most accurate emulation what comes into digital parts of the sid chip. Unfortunately it doesn't sound much like the actual 6581's.
Resid-fp sounds much more like it
I bought this new chipsynth c64 and it has the best sounding 6581 emu I've heard so far, but currently 8580 is lacking distortion (I already made a bug report and its being worked on)
Problem with the 6581 is that the manufacturing process was quite crap what came into producing analog parts of the filter circuitry, lots of variance there and every chip sounds different.
Some of you have noticed that there are 2 external capacitors connected to the sid chip. Datasheet states that those should be matched pair but commodore didn't care and used cheapest available option, instead of accuracy. Also I'm quite sure that the internal parts connected to the different cap sizes are not linear to each other either.
You can tune 6581 filter cutoff by changing capacitor values, and if those are not matched to the same value you can imagine how that affects with everything else in the equation.
I like the resid-fp and chipsynth64 approach to measure the output instead of going to ideal solution from the engineering point of view. Both of those emulators have plenty of different filter curves for us to enjoy.
Which is more accurate then? Its up to your own ears and likings. And if you're not obsessed with sid sounds you shouldn't even care which emulator is the best, just enjoy the tunes. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Commodore even used totally wrong caps on some boards :) (eg in all SX64, but also some regular boards) |
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McMeatLoaf
Registered: Jan 2005
Posts: 108 |
There's a demo of it here you can download and run:
https://www.plogue.com/downloads.html
(10 min per session and you can't save, otherwise it seems to be the same as the full version)
The emulated filter IMHO sounds quite different from reSID-fp or Sidplay3 and clearly closer to real chips. Too bad a few of the emulated chips seem to glitch on some David Dunn tunes, e.g. Elite (both subtunes). |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Quote:The emulated filter IMHO sounds quite different from reSID-fp or Sidplay3 and clearly closer to real chips.
I am willing to bet: In a proper blind test, most ppl will still not be able to tell what is what :) |
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