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[kewatsdop]

I posted a video about sound in Apple Lisa. It may be of interest to the readers of this forum.

The video would have not been possible without Ray's and Tom's help here, so thank you both for helping me a couple of months ago, and I have given you both credit in the video.

Based on what I've learnt, I see a huge potential to experiment with sound and maybe even grow a niche music demoscene around Apple Lisa. For that, due to the rarity of the Lisa, an emulator with faithful Lisa sound subsystem representation is needed, so I'm really looking forward to fixes to the LisaEm which would allow advanced experimentation with sound (in particular polyphony, richer basses, very low-duty square wave). I will be happy to support with tests and comparisons to a physical Lisa.

Once again thank you for the amazing suport here, and I'm hoping to contribute to this forum someday at least a fraction of what I've taken!

The video is here: https://youtu.be/zKRgtbadZ_U
There's also an accompanying article here: http://forgottencomputer.com/retro/sound/#applelisa

[rayarachelian]

I posted a video about sound in Apple Lisa. It may be of interest to the readers of this forum.

The video would have not been possible without Ray's and Tom's help here, so thank you both for helping me a couple of months ago, and I have given you both credit in the video.

Based on what I've learnt, I see a huge potential to experiment with sound and maybe even grow a niche music demoscene around Apple Lisa. For that, due to the rarity of the Lisa, an emulator with faithful Lisa sound subsystem representation is needed, so I'm really looking forward to fixes to the LisaEm which would allow advanced experimentation with sound (in particular polyphony, richer basses, very low-duty square wave). I will be happy to support with tests and comparisons to a physical Lisa.

Once again thank you for the amazing suport here, and I'm hoping to contribute to this forum someday at least a fraction of what I've taken!

The video is here: https://youtu.be/zKRgtbadZ_U
There's also an accompanying article here: http://forgottencomputer.com/retro/sound/#applelisa

That's very impressive. Thanks for this.

I've recently pushed code for RC4, give it a try and see if it works any better. The sound delay bits should be fixed now, though I'm not sure if the frequencies still work exactly the same as on a physical Lisa - this might be slightly off now, not sure. I'll have to test against a real Lisa again to ensure it's the same. Let me know if there's anything else that needs tweaking to get the sound to match.

[kewatsdop]

Ha! I didn't realize the most recent update had this fix in. Thank you! Of course I'll try it ASAP and will let you know.

[stepleton]

Congratulations on your study of Lisa audio! I'm fairly confident in guessing that you've experienced the most complicated sound ever to come out of a stock Lisa :-) I think you are absolutely right and that things can be pushed quite a bit further --- maybe even fuzzy-sounding audio sample playback is possible.

(Thanks for the shout-out, too!)

[blusnowkitty]

I think you are absolutely right and that things can be pushed quite a bit further --- maybe even fuzzy-sounding audio sample playback is possible.

if a 4.77MHz IBM 5150 can push 4-channel Amiga modules down the PC Speaker, there's no reason a Lisa can't do the same thing...

[kewatsdop]

I think you are absolutely right and that things can be pushed quite a bit further --- maybe even fuzzy-sounding audio sample playback is possible.

if a 4.77MHz IBM 5150 can push 4-channel Amiga modules down the PC Speaker, there's no reason a Lisa can't do the same thing...

@blusnowkitty
Exactly. PCs could, though, address the speaker pin directly while Lisa has to push out bits via the shift register. But that should not be limiting given proper handling of IRQs. On the plus side, Lisa has addressable pins to control volume, something PC speaker didn't have. I'm particularly curious about clever uses of that feature.

@stepleton
Thank you! Indeed, I was unable to locate any demos or software with any sound sophistication other than beeps. I hope this video challenges others to try and code much better music than my experiments. Similarly to the 1-bit demoscene productions for the ZX Spectrum, Apple II, etc.

@rayarachelian
I tried the emulator now, version https://lisaem.sunder.net/downloads/lisaem-1.2.7-RC4-2022.04.01-macos-11.0-arm64.pkg, on an M1 Mac. There is definitely improvement, as it is not crashing anymore (yay!), but the sound is not what is expected. From the attached dc42 image, on my Lisa 2 I'm getting coherent music (it should sound like this: https://soundcloud.com/adam-podstawczynski/inishcarra?utm_source=clipboard&utm_medium=text&utm_campaign=social_sharing), from the emulator I'm getting buzzing sounds only.

[rayarachelian]

@rayarachelian
I tried the emulator now, version https://lisaem.sunder.net/downloads/lisaem-1.2.7-RC4-2022.04.01-macos-11.0-arm64.pkg, on an M1 Mac. There is definitely improvement, as it is not crashing anymore (yay!), but the sound is not what is expected. From the attached dc42 image, on my Lisa 2 I'm getting coherent music (it should sound like this: https://soundcloud.com/adam-podstawczynski/inishcarra?utm_source=clipboard&utm_medium=text&utm_campaign=social_sharing), from the emulator I'm getting buzzing sounds only.

Great, that helps, I'll try your code vs LisaEm and try to get the two to match.