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Rub_0201
Registered: Apr 2019
Posts: 28 |
How to mute the voices of the SID?
Hi!
I want to remix my favorite SID tunes. A lot of them have nice rhythm, ideas and melody, but if I hear them more then 10 times in a loop, I get dizzy.
I want to bring more stillness and a different temper in them - making a remix.
My idea is to mute one or two of the voices of the SID and additionally fiddle around with some registers.
I did that with emulators like the C64debugger("24Hours Demo Remix" on YT) and the result is quite nice. Now I want to do it on the C64 itself.
As I am no SID programmer or musician, I have no clue how to do it on the real machine.
I understand fundamental assembly coding, but I am far from doing fancy stuff.
So I need your help! |
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Bansai
Registered: Feb 2023
Posts: 54 |
There is muting, but only for voice 3. See $D418 bit 7.
https://www.oxyron.de/html/registers_sid.html |
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aeeben
Registered: May 2002
Posts: 46 |
If you don't need the filter, you can mute voices 1-2 by routing them to filter (poke54295,1 / poke54295,2) and turning off all filter types (poke54296,15).
But Deetsay's DJ SID mixer is probably the way to go! :) |
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Stone
Registered: Oct 2006
Posts: 177 |
Some players have a lookup table for the voice offsets. Look for the byte sequence $00,$07,$0e. Then you can change whatever voice you want to mute by setting it to $19. This will redirect writes to read-only/unused registers. |
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Rub_0201
Registered: Apr 2019
Posts: 28 |
The sound result with the buffered routine is not the same. :-(
Percussion instruments sound dull and powerless.
Hearable especially on "Beat to a pulp" from NE7 (voice 3).
Any ideas?
I still look for a bug in my code, but I think it is related to the different technique/timing of writing to the IOs. |
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spider-j
Registered: Oct 2004
Posts: 505 |
As "Beat to a Pulp" uses a quite "new" routine (GT1) it's verly likely there's something wrong with your code.
I just threw the SID through my "sidanalyzer" script / code which uses the above mentioned approach and everything sounds fine to me, when (un)muting voices:
https://trans.jansalleine.com/csdb/sidanalyzer-bttp.prg |
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Rub_0201
Registered: Apr 2019
Posts: 28 |
Quote: As "Beat to a Pulp" uses a quite "new" routine (GT1) it's verly likely there's something wrong with your code.
I just threw the SID through my "sidanalyzer" script / code which uses the above mentioned approach and everything sounds fine to me, when (un)muting voices:
https://trans.jansalleine.com/csdb/sidanalyzer-bttp.prg
Thanks Spider-j!!
With your routine "Beat to a pulp" sounds like it should be . Now I hear the exact difference with muted voices 1 und 2!!
I'l do some bug hunting.... |
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Rub_0201
Registered: Apr 2019
Posts: 28 |
Well...I think there is a problem in my code and in the general aproach.
I recorded voice 3 of "Beat to a pulp" with:
1) C64jukebox with SIDPlay2 recorded with Chrome Audio extension
2) spider-j routine recorded within VICE 3.8
3) my routine recorded within VICE 3.8
#2 is better than #3, but #1 is far better than the latter.
The SID model and resampling, buffer, filter, etc. did not change this behavior in VICE.
Here are the files:
https://www.dropbox.com/scl/fo/gcjp4k8qmc9uf6vn1cg99/AEP9FGA1Yy.. |
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spider-j
Registered: Oct 2004
Posts: 505 |
@Rub_0201:
Could it be that that sidplay2 is configured to emulate 6581 SID and your VICE to emulate 8580?
Your recordings from VICE could be 8580 "filter holes" because on 6581 cutoff values from $00 are audible and on 8580 only values from $01. Although even listening to it with proper 6581 emulation the SID voice 3 does sound a bit weird. So I'm not really sure about that. Maybe not the best test case.
To get your routines right I'd start with
1.) a SID tune that doesn't use filters at all - so the even most crappy emulation shouldn't have much problems to playback
2.) and then a SID tune that uses "mild" filters AND only compare results with a somewhat current SID emulation
Another problem with the tune you're referring to is, that is was done in GT1 and nobody other than the author knows if it was ever tested on real hardware. So it may be that it sounds "better" on old / outdated emulation, because it was composed on old / outdated emulation :-) |
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Burglar
Registered: Dec 2004
Posts: 1137 |
you can mute channels with JSIDPlay2 V4.10, and u can also export to wav. personally, I only use the cli interface, but I guess same features are in the gui too. |
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Rub_0201
Registered: Apr 2019
Posts: 28 |
I hope, the emulator is acurate and the test results are similar on the real hardware.
I've set the SID to 6581 imho for the tests.
--------------------------
This song is a challenge :-) And I love this song since 35 years. Well, the Amiga version - Met Romeo Knight on X2023.
Challenge accepted - I used C64 Debugger to see the timing of the IO Writes and the new version of my play routine is good enough now!
Voice 3 only:
https://www.dropbox.com/scl/fi/adcy922bq5j06hmsqofxc/Rub_V2_vic.. |
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