pouët.net

To my ears, most Amiga demos and games that use 4-channel mods tend to have a distinctive texture to the sound, most likely due to the 8-bit nature and low sampling rates of the mods themselves, compared to PC modules that use 16-bit and sound much closer to commercial music, etc.

Well, I've heard a few demos like Metropolice, Ocean Machine, Outside Planet Earth and Incision that don't bother with mods at all, but use full-blown stereo MP2 or MP3 tracks that sound awesome in their clarity, just like MP3s in PC demos.

I read recently, and I never knew before, that Paula could be programmed to combine two 8-bit channels into one 14-bit channel and output audio of that quality - and with four channels to begin with, stereo sound is a cinch! So is this what those demos use?

Yes, that's what many demos use for streamed music (though I think they usually use ADPCM compression, MP3 is a bit too fancy for these machines, especially if you want to run a demo at the same time). 28 KHz 14-bit is still not quite the same as 44 KHz 16-bit, especially when there's filtering involved.

The Falcon can replay MP2 files if you devote the DSP to that task.

MP3 is not CD-quality anyway.

Show me one 060 demo that plays an MP3 whilst rendering something meaningful on the side, apart from what Scali pointed out. It's (modified) ADPCM afaik - and more often than not it sounds a little grainy so no 44KHz.

I was going to say Metropolice, as there's an MP3 file there in the LHA file, but then I looked further and saw a file called "soundtrack.wav", so I guess that's what's played - so why feature the MP3 separately?

I had a problem with the demo Starstruck years ago when I was recording demos - do I go for the genuine Amiga audio version (which sounds 8-bit and mono) or do I instead go for the MP3, which sounds much clearer? In the end, I had to go for the MP3, but it was a wrench because it wasn't genuine Amiga audio. Was there ever a version of Starstruck that used the same channel-combining?

So that people don't have to go to pouet and ask "where can I find a full-quality version of the soundtrack"?

:D

Hahaha, Johannes :) Yes, that's exactly why I put the mp3 in the archive :)

"Decoding ADPCM (or similar) is reasonably quick. Our implementation takes perhaps 10 scanlines on 060 for decoding a 22kHz mono stream to 14bit output." .. hardly CD quality there :)

OK, near-CD quality sound - it's a lot better than 8-bit, that's for sure!

Err, bit depth is much less important for perceived quality than sampling rate. This is true in general, and in particular there have been some blind tests recently confirming that a lot of modern (brickwalled) music sounds just the same at 8-bit and 16-bit.

What Saga said. I'd much rather listen to 32KHz 8-bit than 22Khz 16-bit (unless the music has a lot of very quiet, subtle parts).

(Why not >32Khz? Because my ears can't hear frequencies above 15.5KHz)

You can find Kalms' ADPCM encoder/decoder here by the way: https://code.google.com/p/unitedstatesofamiga/downloads/detail?name=ADPCM-Kalms-2.1.zip&can=2&q=

I guess some of the quantization noise could be moved out of the hearing range with high enough sampling rate and proper noise shaping?

If you record it on one of these, then it's CD quality
http://www.amazon.de/TDK-CD-ING-2/dp/B0000C7AZ1/ref=sr_1_fkmr0_1