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Can the STE's PCM sound chip play Amiga modules?


Foebane

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Amiga was launched in 1985. Although, there were no many games until late 1987.

All it changes not fact that this thread is so f*d up with total off topic crap ...

Hopefully next year will be better .

 

I know Amiga was launched in '85.

Off-topic? This is an Atari board, right? And the Amiga was very nearly Atari, right? So how is it off-topic?

No, next year will not be better.

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Off-topic? This is an Atari board, right? And the Amiga was very nearly Atari, right? So how is it off-topic?

 

What is so hard to grasp? READ THE TITLE OF THE THREAD. :P It is OFF -TOPIC in relation to the original question and point of the thread.

"Can the STE's PCM sound chip play Amiga modules?" ;) Geez you MADE this thread so you should know this. :D
Edited by OldSchoolRetroGamer
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Because "closing" threads is generally not done, here is an idea, just ignore it or do not respond if you are sick of it, there is even an IGNORE THIS TOPIC option you can click at the top of page. ;)

 

I can't just ignore what I started, especially if any Amiga-bashing happens, which I'll have to answer to.

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Best for MOD playback is Gravis Ultrasound than Awe64gold and msdos... Samples was interesting during early 90s.So in that time Amiga 500/600/1200 was amazing computer for audio.Nowadays YM soundchip in ST provides its original sound.So in time when any mobile phone got better codec for samples.3ch YM is little miracle!

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I'd love to rehash some of the comparisons and Amiga VS ST stuff ... or business decisions, or merits of the STe or Falcon going on in this thread, but don't have the time to read through it right now. Instead, how about something on point with the original topic?

 

Hopefully noone's posted this video already:

 

 

Nice selection of MOD players on the STe (and one on the ST, plus native Amiga playback for reference). One of those uses the 50 kHz mode with multiplex mixing, which I believe is sample-interleaving (ie a 50 kHz channel effectively becomes 2 25 kHz channels by interleaving samples on a byte basis when mixing rather than adding them together). The advantage there being slightly lower CPU overhead, but more importantly the ability to keep the full 8-bit resolution intact and not deal with clipping or quality loss. (the latter would certainly occur if you mixed a bunch of 8-bit samples to 16-bit resolution and output the upper 8-bits to the sound hardware ... some PC sound drivers for 8-bit sound blaster cards do this)

 

Incidentally, the multiplex-mixed MOD player seems closest to the Amiga player to my ears at least. (though the comparison for all of the 25 kHz and 50 kHz players are pretty close ... the 12.5 kHz one is obviously another story, as is the ST player using the YM2149 for PCM)

 

 

I forget if the STe has 2 DMA sound channels or not. Wikipedia mentions stereo mode being handled with byte interleaving LRLRLR style, which implies there's only one DMA channel actually being used. Regardless of that, I was also unsure if the 50 kHz mode functioned as distinct left and right stereo channels or not. (ie given the LRLR interleave, does stereo have half the max sample rate of mono, or does the stereo mode allow for double the DMA bandwidth of mono? ... I assumed it works as one left 50 kHz 8-bit channel and one right 50 kHz 8-bit channel, so the latter case of 2x the bandwidth) It might be similar to the PWM audio in the Sega 32x in as far as having a 'mono' mode that simply writes the same data to left and right buffers while stereo just allows either to be written to individually. (with stereo and mono modes having the same resolution and frequency limits) Chilly Willy would know much more about the 32x example if he's around.

 

There's also various 8-channel mods among other things on both the Amiga and STe. (Turrican II's intro on the Amiga uses software-mixed music, going well beyond Paula's native limitations; it's rather impressive they managed to make the ST version sound such a reasonable approximation given the limitations there ... I believe that's a normal 4-channel MOD, but some other tricks might be thrown in)

 

I'm not sure if Turrican II uses the 'effects' mode of the Amiga or just software mixes in the normal 4-channel mode. Effects mode (only one left and one right channel, but with 6-bit logarithmic volume control) on the Amiga would be much more in line with the STe's capabilities and best suited for software mixing with more demand for stereo panning effects. The STe would probably have a notable advantage here between the higher sample rate and LMC 1992 mixing/effects chip to work with. (ie not as good for games, but more useful for professional audio applications)

 

The 8-bit sound limit is still a pretty big hurdle for the professional audio end of things, though, and complicates good quality software mixing (you need good optimization to avoid clipping while also avoiding overly quiet samples that end up effectively much less than 8-bit resolution). You could potentially wire the Amiga to be 16-bit mono by merging the left and right channels while in effects mode and setting the volume one one to be 255 times as loud as the other, adding together to 16-bit linear PCM (rather than the 14-bit nonlinear hack), and it could have done this out of the box if Paula simply allow for a mono switch in software. But the STE, OTOH should actually allow this to be done given the LMC 1992's functionality allowing left and right sound channels to be panned left, center, and right, or effectively leaving both as mono. (I'm not sure of the volume granularity on the LMC 1992, but if it allows any combination of settings such that one channel is approximately 255 times as loud as the other, you could get 16-bit mono out of it)

 

On a side note, the STe audio is also somewhat comparable to the Sound Blaster Pro, or somewhat more capable given the 44 kHz 8-bit mono and 22 kHz 8-bit stereo limitations of that. (it also beat that to market by 2 years) The SB Pro also had a whole mess of FM synth channels with its dual OPL2s, of course, and the somewhat more feature-rich OPL3 in the SB Pro 2.0 (and SB-16) later on, but those got fairly mediocre use, almost never in conjunction with PCM and are mostly relevant for games rather than professional audio/music applications. (I'd argue the ST would have gotten much more use out of such FM synth chips had it ever had them ... due to the UK/Euro chiptune scene: you saw plenty of that on the Mega Drive; but that's another story as well)

 

The sound hardware of the STe may not have been expressly designed for professional applications over games or home entertainment, but it certainly seems to be more useful for such and shines best next to contemporaries when used as such. (shame it wasn't added earlier, though ... like with the 1040 ST or MEGA ST, even without the LMC 1992)

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