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Bamu®
Account closed
Registered: May 2005
Posts: 1332 |
New waveforms...
Last year I have heard something about 'new' SID waveforms (found by SounDemoN)
So, when we finally can use these waveforms with a standard editor?
Does anybody have an idea?
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assiduous
Account closed
Registered: Jun 2007
Posts: 343 |
just checked TestBitX4 on a real C64 and indeed the noise doesnt sound very good(similar to Hoxs64). locking the testbit in reSID is risky atbest,because the noise emulation is not very well modeled. |
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Jammer
Registered: Nov 2002
Posts: 1289 |
well, i see that i will have to pester lasse a bit about thinking of hoxs' sid library :P resid disappoints me too often recently :P |
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Analmux
Account closed
Registered: Feb 2008
Posts: 1 |
Hello, I'm new to this forum. I come from the Atari8bit.
Pokey is the soundchip of A8. It has similar features for special waveforms supported by random shift registers, or 'polycounters'. Pokey has a few polycounters (p.c.s) with different lengths. SID has one 23bit p.c. versus Pokey has 4bit, 5bit, 9bit, 17bit p.c. All have a bitpattern that repeats after a certain time. The n-bit p.c. repeats after 2^n -1 clockcycles.
There's a standard feature to combine two 8bit registers for 16bit frequency control. By this feature some very interesting sounds can be generated. They sound like distortion guitars. It's also possible to control the desired pitch. It relies on the 9bit polycounter, which repeats itself after 511 clockcyles (=4.5 rasterlines).
Contrary to the SID, it's not needed to reset polycounters with a timer-interrupt. Pokey 'resets' itself now and then.
I can imagine that on SID the polycounter reset must be executed often, but when the timing of this interrupt is locked at f.e. once every 8 scanlines, then still a lot of interesting sounds should be possible with this, as on SID you still have the 16bit pitch register to do fine-tuning. At least this is how it works on Pokey, as 9bit polycounter resets after 4.5 scanlines.
So, how often do you need to do this reset procedure on average?
I'd be interested in precise code for doing the new waveforms on C64 (I also have a few of those). I'd like to try on one of my real machines.
I also wonder if it's possible on SID to reset or synchronize the start of a waveform with a certain display- or CPU-event.
How does SID deal with the noisegenerator anyway? Does it take samples using some kind of countdown timer which is configured by the 16bit pitch settings?
I have the experience (at least with Pokey) that it's possible to select a waveform from a continuum of possibilities if you have the correct control for relative timing between the 'sampling frequency' of a SID voice and the 'resetting process'.
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dalezy
Registered: Apr 2002
Posts: 475 |
jammer, $19 isn't too new, you should try $59 and $58+$80 in x-speed as well to get some good percussions =)
other than that, did we ever elaborate on the carrier-bug/feature that laxity's jch player came along with? when laxity's player came out i found out the random-letterhitting way that $81 being played at f0 (or fe? should check again) makes up for a good downsampled drumloop-kind of effect in case you have something drum-alike running on channel 1. that one only works in 21.g4 though, i couldn't reproduce it in 21.g5.
i wish i could explain that one, seems like it was really just an unintended bug, and to top it - i didn't even check if it works on a real sid, as i did the testing in vice. =) |
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Jammer
Registered: Nov 2002
Posts: 1289 |
Quote: jammer, $19 isn't too new, you should try $59 and $58+$80 in x-speed as well to get some good percussions =)
other than that, did we ever elaborate on the carrier-bug/feature that laxity's jch player came along with? when laxity's player came out i found out the random-letterhitting way that $81 being played at f0 (or fe? should check again) makes up for a good downsampled drumloop-kind of effect in case you have something drum-alike running on channel 1. that one only works in 21.g4 though, i couldn't reproduce it in 21.g5.
i wish i could explain that one, seems like it was really just an unintended bug, and to top it - i didn't even check if it works on a real sid, as i did the testing in vice. =)
well, i should check it on a real thing i guess because so far the only difference is audible in $49, the rest with $x9 is always the same :P i will do the test :D i guess without multispeed you won't get reasonable effects in this matter ;) |
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Soren
Registered: Dec 2001
Posts: 547 |
Damn you guys! I was using that particular bit for something else in my new player/editor, BUT I made an addition so one can use testbit aswell, not that it will ever get as amazing as what Soundemon has done with testbit, but it's the same theory, you just don't have the right wave-cycle based timing when using it in normal sid players, which is also why you can't control it as note-frequency.
So anyways, now I have 4 ways of handling my wave+freq+finetune tables... finetune being calculated ofcourse, so you can do +/- finetuning that works like on synths.
Anyways, must get back to coding... need to be able to compose again soon! :-)
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Conrad
Registered: Nov 2006
Posts: 833 |
Jeff: Many months of coding your player will for sure pay off at the end. :)
btw, anyone had a go using:
01: 61 00
02: 51 00
03: FF 01
...at 4x speed with pulse width of $00 or so?
With notes like G-2 and A#3 you can get some freaky electronic sounds, this being in GT of course - haven't tried it on the real thing yet. |
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Soren
Registered: Dec 2001
Posts: 547 |
Conrad: yep, it has paid off... worked on the player during a bit more than a year and the editor is very close to being done aswell. :-)
and about the wave stuff... it's all a matter of some simple waveshaping. |
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dalezy
Registered: Apr 2002
Posts: 475 |
conrad, i get about the same sound with any other combination where $51 is involved, been using it quite often lately =) |
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mstram
Account closed
Registered: Dec 2013
Posts: 112 |
Is this now working in Vice (2.4.x) ?
I'm seeing some tunes with xC1 waveforms, and I was wondering what they were, until I found this thread.
Or maybe Vice / Resid is just ignoring the C1 ?
I'll have to see if the tunes are on any of the "recorded by real SID -> MP3" sites, to compare the sound. |
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