emkay Posted September 10, 2019 Share Posted September 10, 2019 17 minutes ago, patjomki said: Taking all CPU power is prohibited. ? So, how can I get variable duty cycle? Or is there a mistake in the wikipedia article? https://en.wikipedia.org/wiki/POKEY#Features "Per-channel volume, frequency, and waveform (square wave with variable duty cycle or pseudorandom noise)" Two tone is an "overlaid" result of two 16 bit channels. The have to be set "modulo", to get a recognizable waveform. If the frequency of both channels isn't set correctly, you just get weird noise. This makes variable "duty cycles" impossible. You could build those Duty Cycles using software as ROger wrote. But you also can do that, using the "Filter" to produce variable Duty Cycles. "Filter" is needed, because there is a direct common start programmable. Using Cancelling to build those Duty Cycles is much more problematic, as the Start of every Channel isn't 100% to handle. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 10, 2019 Author Share Posted September 10, 2019 I am actually going to experiment with hi pass plus SKCTL next. Try to see what modulating the first two channels with hi pass gets me. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 10, 2019 Author Share Posted September 10, 2019 1 hour ago, emkay said: Two tone is an "overlaid" result of two 16 bit channels. The have to be set "modulo", to get a recognizable waveform. If the frequency of both channels isn't set correctly, you just get weird noise. This makes variable "duty cycles" impossible. You could build those Duty Cycles using software as ROger wrote. But you also can do that, using the "Filter" to produce variable Duty Cycles. "Filter" is needed, because there is a direct common start programmable. Using Cancelling to build those Duty Cycles is much more problematic, as the Start of every Channel isn't 100% to handle. What if you use that timer reset trick pavros discovered for $Cx mod 3 bass? Quote Link to comment Share on other sites More sharing options...
emkay Posted September 10, 2019 Share Posted September 10, 2019 48 minutes ago, Synthpopalooza said: I am actually going to experiment with hi pass plus SKCTL next. Try to see what modulating the first two channels with hi pass gets me. This tune is using 2 tone with generator 4 and the high cymbal sound is high pass . The Bass , btw. ist using an approximation, to warble through all orbits of the bass generator. In the last seconds of the tune it changes to Filter modulation . It is done in the patch 8 version of Analmux' RMT patches. Quote Link to comment Share on other sites More sharing options...
emkay Posted September 10, 2019 Share Posted September 10, 2019 38 minutes ago, Synthpopalooza said: What if you use that timer reset trick pavros discovered for $Cx mod 3 bass? Could be useful to check out on the real thing. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 10, 2019 Author Share Posted September 10, 2019 Altirra emulates this correctly too i think Quote Link to comment Share on other sites More sharing options...
R0ger Posted September 10, 2019 Share Posted September 10, 2019 2 hours ago, Synthpopalooza said: What if you use that timer reset trick pavros discovered for $Cx mod 3 bass? Pavros syncs timers to polynomial generators. For full control over PWM with filter you need something different. You need to sync 2 channels to each other. Typically you will sync 1 and 3, and use "high-pass" filter on those. You can use STIMER, or setting frequency to 0 for some time. That time can be greatly decreased by setting channel 1 and 3 to 1.79MHz source. That can't be done with channels 2 and 4 though. After you reset both channels, you set them them to different frequencies for some defined time. During that time the phases of the two channels will gradually shift away from each other. You can control how much by the frequency difference and the time. Then you set them to the same frequencies. Quote Link to comment Share on other sites More sharing options...
R0ger Posted September 10, 2019 Share Posted September 10, 2019 52 minutes ago, Synthpopalooza said: Altirra emulates this correctly too i think At the moment I don't know about anything which Altirra doesn't emulate. I haven't tested some of these thing of yours though on real hardware. Might be useful if you report any discrepancies. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 10, 2019 Author Share Posted September 10, 2019 The SKCTL and reverse 16 examples I posted so far are 100% good on real hardware. The rest remains to be seen Quote Link to comment Share on other sites More sharing options...
foft Posted September 11, 2019 Share Posted September 11, 2019 8 hours ago, R0ger said: At the moment I don't know about anything which Altirra doesn't emulate. I haven't tested some of these thing of yours though on real hardware. Might be useful if you report any discrepancies. I think this particular case still needs work? I tried to download the latest altirra 3.2 to check but had config issues (crash on boot with any os), so not sure. I think the trace on here is from that, but not 100%. Pokey vs EclaireXL in that case. http://www.64kib.com/redmine/issues/67 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 11, 2019 Author Share Posted September 11, 2019 I have latest and will try it here. Quote Link to comment Share on other sites More sharing options...
R0ger Posted September 11, 2019 Share Posted September 11, 2019 6 hours ago, foft said: I think this particular case still needs work? I tried to download the latest altirra 3.2 to check but had config issues (crash on boot with any os), so not sure. I think the trace on here is from that, but not 100%. Pokey vs EclaireXL in that case. http://www.64kib.com/redmine/issues/67 Interesting. You have to reset Altirra settings sadly. I had the same issue. Quote Link to comment Share on other sites More sharing options...
foft Posted September 11, 2019 Share Posted September 11, 2019 (edited) I tried Altirra 3.2 (oddly it worked after I rebooted my pc!) and confirmed it differs from my 600XL (with an original pokey). Altirra and pokeymax in the same 600XL match, so its not down to the post-pokey circuitry. Edited September 11, 2019 by foft Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 11, 2019 Author Share Posted September 11, 2019 So in this particular case, does behavior differ for different POKEYs, or just between it and clones? Quote Link to comment Share on other sites More sharing options...
Rybags Posted September 12, 2019 Share Posted September 12, 2019 I don't think there's any audio differences among Atari's Pokey revisions. Or if the warm-up differences that are documented differ among them. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 17, 2019 Author Share Posted September 17, 2019 So here are a couple of renditions of the Area 1/Area 3 theme from the NES shooter Zanac zanac1.mp3 zanac2.mp3 Both use 2-tone mode ... in the first instance, channel 1 is silenced. In the second, channel 1 is permitted to play the carrier frequency atop the modulated one. This improves the sound, but at a cost: Channel 1 also feeds through the other channels, and when it decays, it puts an awkward volume stutter into the tune. Any ideas how to fix this? Binaries below: zanac.asm zanac.s zanac2.asm zanac2.s 2 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 17, 2019 Author Share Posted September 17, 2019 And another ... the overworld theme from Super Mario World. super mario world - overworld theme.mp3 This one uses AUDCTL=$60 and two tone mode on $Ax, which is the very famous "Save to Cassette" setting familiar to all of us. A very ringy bell timbre. The note table for this setting is up in the thread. marioworld1.asm marioworld1.s marioworld1.xex 2 Quote Link to comment Share on other sites More sharing options...
R0ger Posted September 17, 2019 Share Posted September 17, 2019 Those MP3s are from real hardware ? Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 17, 2019 Author Share Posted September 17, 2019 Altirra emulator. Haven't checked on XL ... tho I can confirm Zanac behavior is 100% accurate on a POKEY equipped Atari 7800. Quote Link to comment Share on other sites More sharing options...
R0ger Posted September 17, 2019 Share Posted September 17, 2019 11 minutes ago, Synthpopalooza said: Altirra emulator. Haven't checked on XL ... tho I can confirm Zanac behavior is 100% accurate on a POKEY equipped Atari 7800. That's what I wanted to hear. Won't have time to experiment with it too much though. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 20, 2019 Author Share Posted September 20, 2019 Can also confirm Mario Overworld 100% on real HW. Yay. 1 Quote Link to comment Share on other sites More sharing options...
emkay Posted September 28, 2019 Share Posted September 28, 2019 You know that all your energy will end in the nirvana? On the Atari almost no one wants music. There is a dedicated detune, they like. If you correct things, 99% of them will ignore or dislike it. This is the most advanced peace of music , playable on a real Atari. See the reaction to it. Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted September 28, 2019 Share Posted September 28, 2019 emkay, Trying to understand what this was all about..... Crockett sounds perfectly fine... but what's this have to do with anything? Is there suppose to be problem? 1 Quote Link to comment Share on other sites More sharing options...
777ismyname Posted September 28, 2019 Share Posted September 28, 2019 2 hours ago, emkay said: You know that all your energy will end in the nirvana? On the Atari almost no one wants music. There is a dedicated detune, they like. If you correct things, 99% of them will ignore or dislike it. This is the most advanced peace of music , playable on a real Atari. See the reaction to it. Nothing wrong with this tune, but “most advanced” is highly subjective. 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted September 30, 2019 Author Share Posted September 30, 2019 Very good. If someone makes a Miami Vice game, there you go. Does this use a lot of hi pass filter? Quote Link to comment Share on other sites More sharing options...
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