ACNews
#60
15 декабря 2015 |
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AY music with digital samples - in ProTracker 3.X in General Sound.
AY music with digital samples by Alone Coder Playing digital samples in CPU free time is easy. Combining AY with General Sound was also a known (yet unreleased) idea. But until now, there wasn't any editor that allowed digital samples combined with on-int AY music. For this, I used the most straightforward method: I added a special command 8snn in Pro Tracker. "s" is sample number, "nn" is for note. (General Sound plays only 3 Amiga octaves with note values #24 to #4A.) If you use this command in AY's channel A, the sample will play in General Sound's channel A. B to B. C to C. So you have 9 channels in this editor: 6 AY channels (TurboSound) plus 3 digital channels. Of course, if you want to use your music in AY only release, you can limit your channels. So what is the workflow in this experimental version of Pro Tracker? 1. Prepare a MOD file with your samples (uncycled). 2. Put it on TRD as "filename.i". 3. Run Pro Tracker. 4. Load your MOD in it (nothing happens apparently but the samples will load in General Sound). 5. Write your song :) Note, if you don't load your MOD, General Sound will buzz at 8snn command. That's because in General Sound "Play FX" command doesn't work if you use it with non-existing sample. Maybe I must clear the samples at the start of Pro Tracker? Contact me with your ideas. * * * If we play music on AY and GS at the same time, we need to synchronize the replay speed between ZX and GS (defined by framerate), and match the pitch (defined by AY clock). So we need a standard for these values. If I remember correctly: 48K: 50 Hz, 1750000 (AY is an add-on) 128K: 50 Hz, 1773400 Scorpion/KAY: 50 Hz, 1750000 ATM Turbo: 50 Hz, 1750000 ZX Evo default: 48.83 Hz, 1750000 ZX Evo 48K: 50 Hz, 1750000 ZX Evo 128K: 49.34 Hz, 1750000 Pentagon (f=14318000): 49.94 Hz, 1789750 (AY is an add-on) Pentagon 2.6ббLE: 50 Hz, 1792000 Unreal Speccy default: 50 Hz, 1774400 50 Hz is the most popular variant without doubt (a lot of programs count time with this). The only trouble is AY clock. GS was initially developed for Scorpion and KAY that have AY at 1750000 Hz. Maybe this will be the best option. ZX Evo can emulate it in 48K timing mode. Default AY clock in Unreal Speccy is strange anyway, but there is an option for 1750000 Hz in it. No 128K is known to have GS attached. So the only machine that has problems with playing such songs is Pentagon. Maybe tone values must be shifted in realtime to play there? Changing frequency tables will affect slides; changing finetune in GS samples will affect sample replay time (that's not that noticeable though). If we play samples on the same AY we can only care about correct number of t-states per frame, because AY is generally synchronous with the CPU. Pentagon is far from ideal 70000 t-states, 128K is somewhat closer. And turbo mode might be switched on... So our replayer must detect the number of t-states and change the frequency table for digital samples
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