Cybernoid Posted December 14, 2004 Share Posted December 14, 2004 Just a little 6-bit 4kHz sampling PCM demo. :wink: Run this in the emulator with 128k memory...wait... then listen... Happy Holidays! gatesxmas.zip Quote Link to comment Share on other sites More sharing options...
Cybernoid Posted December 14, 2004 Author Share Posted December 14, 2004 Here is another experiment with some higher fidelity audio. This time the audio is sampled at 16kHz, but I am doing some tricks to vibrate the speaker faster than the ear can hear it to cause some half volume samples. This creates a pseudo-7bit PCM playback and works great on the emulator. I need to try this on the real hardware. I would guess that it might cause some frequency aliasing, and you might hear some unwanted high frequencies... pcm_test1.zip Quote Link to comment Share on other sites More sharing options...
Cybernoid Posted December 14, 2004 Author Share Posted December 14, 2004 Oops. Had a bug in the code. This fixes a few hisses and pops... plastic_pop.zip Quote Link to comment Share on other sites More sharing options...
Goochman Posted December 15, 2004 Share Posted December 15, 2004 Im not actually sure what I am supposed to be hearing - though I tried it on Atariwin 3.1 emu Quote Link to comment Share on other sites More sharing options...
Cybernoid Posted December 16, 2004 Author Share Posted December 16, 2004 Well, you are just supposed to hear some audio. Just as I expected, the 6bit+ doesn't work on the real hardware, showing that frequency aliasing is not really emulated properly. Well, it works but with a horrible hiss. 6bit PCM at 13.3KHz sampling rate it not that bad though... Quote Link to comment Share on other sites More sharing options...
Sheddy Posted December 18, 2004 Share Posted December 18, 2004 Nice one Cybernoid - Pretty good sound quality Just curious regarding your first one - 6 Bit, 4Khz. (I'm too lazy to dissable your code I guess) If your're not wiggling the volumes faster than the sample rate like the other example, how're you doing it then? thanks! Quote Link to comment Share on other sites More sharing options...
miker Posted December 18, 2004 Share Posted December 18, 2004 maybe use some more mem-banks Quote Link to comment Share on other sites More sharing options...
Cybernoid Posted December 18, 2004 Author Share Posted December 18, 2004 Nice one Cybernoid - Pretty good sound quality Just curious regarding your first one - 6 Bit, 4Khz. (I'm too lazy to dissable your code I guess) If your're not wiggling the volumes faster than the sample rate like the other example, how're you doing it then? thanks! Thanks! Yeah, that one was pure 6bit. Here are a few more 6bit 13.3kHz samples, and the source code. These sound great on the real hardware. The code uses all 4 pokey voices in volume only mode for an effective 6bit range. There are some more experiments I am working on, so it may still be possible to do better than 6bit. I am ultimately working on a player for the MaxFlash Cart and for MyIDE. The Flash Cart code is written, but I still have a few more questions for Steve... I have talked to Mr. Atari as well. ~C~ wavplay.zip Quote Link to comment Share on other sites More sharing options...
Cybernoid Posted December 19, 2004 Author Share Posted December 19, 2004 Oops, forgot the Samples... sixbitpcm.zip Quote Link to comment Share on other sites More sharing options...
Sheddy Posted December 20, 2004 Share Posted December 20, 2004 Thanks for sharing the code Cybernoid - I'll be looking at it with a fine tooth comb - My experiments with combining channel volumes on samples were awful! In fact I was even thinking that when using volume only the full excursion of the speaker was effected by just one channel. Nice to know it can be done Quote Link to comment Share on other sites More sharing options...
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