Spectrum Computing

When you're listening to AY music or playing games with AY sound, what do you use, mono or stereo? The original 128K machines as released by Sinclair and Amstrad were of course mono, but stereo hardware mods are common and most emulators have a stereo sound option.

By 'hard-panned stereo', I mean that the side channels are panned 100% to the left and right, so that if you're listening with headphones, each ear can only hear one of the side channels. Think early Beatles stereo mixes, and a lot of other '60s music. This configuration is common in emulators as well as in hardware.

'Soft-panned stereo' is the less extreme version where the side channels are only slightly panned, say by around 50%. Not so many Spectrum emulators do this, but AY emulators usually have the option as well as some hardware mods.

So which one do you use? If you use more than one just pick the one you prefer the most.

Strictly mono for me. The AY chip was not meant to be a stereophonic sound source; channels were meant to be mixed together internally, much like they are mixed down in analog synthesizes.

I think the confusion comes either from the imprecise terminology used by GI, or by those who read into the term “channel” incorrectly. A more appropriate choice would be “voice,” rather than “channel.” So, the AY chip doesn’t offer three channels of sound, but rather three-voice polyphony. (To be even more pedantic, though, the AY simply has three tone generators.)

In the early days of stereo recordings, especially before digital reverbs, the two channels available to the end user were regarded as a novelty, rather than a true source of stereophony. Nor were there practical means of capturing a true stereo source aside from recording everything with a pair of microphones. I don’t think there even were pan knobs on early consoles, so hard-panning was probably due to the engineers arbitrary patching individual channels of multitrack tapes to the two channels of the master tape. Besides, early studio tape recorders had a low track count, and multiple overdubbing was either technically unfeasible or prohibitively expensive.

Going back to the AY chip, though. Multiplexing was a common technique for AY music and sound effects. It worked precisely because there was no spacial separation between the voices. Introducing faux (arbitrary, rather) stereo, only causes confusion and the sense of disconnect of sound and gameplay in most cases, in my book.

By stereo, I'm presuming you are referring to one AY sound chip having its channels (tone generator outputs) mixed to the left and right stereo output. Rather than two AY chips, one connected to the stereo left channel and the other connected to the stereo right channel.

Mark

Heh, well this poll turned out even more skewed than the Manic Miner one did.

Ast A. Moore wrote: ↑Sat Jun 30, 2018 11:12 am Strictly mono for me. The AY chip was not meant to be a stereophonic sound source; channels were meant to be mixed together internally, much like they are mixed down in analog synthesizes.

I think it's going a bit far to say that the AY was intended to be used in mono only and so it's the 'one true way' of listening. The datasheet mentions that "these channels may be individually amplified through separate channels for more exotic sound systems". So it sounds like they were at least considering stereo. The Amstrad CPC even had stereo output from the AY chip when using the headphone jack.

Ast A. Moore wrote: ↑Sat Jun 30, 2018 11:12 am I think the confusion comes either from the imprecise terminology used by GI, or by those who read into the term “channel” incorrectly. A more appropriate choice would be “voice,” rather than “channel.” So, the AY chip doesn’t offer three channels of sound, but rather three-voice polyphony. (To be even more pedantic, though, the AY simply has three tone generators.)

What 'confusion' are you talking about? People deliberately make stereo AY interfaces and AY music designed to be listened to in stereo. I don't think it's because they were confused when reading the documentation.

Ast A. Moore wrote: ↑Sat Jun 30, 2018 11:12 am Going back to the AY chip, though. Multiplexing was a common technique for AY music and sound effects. It worked precisely because there was no spacial separation between the voices. Introducing faux (arbitrary, rather) stereo, only causes confusion and the sense of disconnect of sound and gameplay in most cases, in my book.

Yes, some games do suffer when played with stereo sound because they simply weren't designed for it. But a lot of modern games and music are taking advantage of stereo and don't have these issues. Going the other way, some AY tunes are designed to be heard in stereo but don't work as well in mono. It's common to have parts duplicated across both side channels in a way so that they combine and sound 'heavier' when listening in stereo. When played in mono, this can result in the two channels being out of phase with each other, so they cancel each other out and the effect is lost.

djnzx48 wrote: ↑Sun Jul 01, 2018 6:11 am Heh, well this poll turned out even more skewed than the Manic Miner one did.

Were you looking for a different result?

djnzx48 wrote: ↑Sun Jul 01, 2018 6:11 am I think it's going a bit far to say that the AY was intended to be used in mono only and so it's the 'one true way' of listening. The datasheet mentions that "these channels may be individually amplified through separate channels for more exotic sound systems". So it sounds like they were at least considering stereo. The Amstrad CPC even had stereo output from the AY chip when using the headphone jack.

CPC music can be a bit hit and miss in stereo as many developers went with the assumption that people would just use the built in mono speaker and thus worked with what sounded good on that (although the system, including BASIC itself, was geared around a left, right and centre channel). The later Plus models output sound entirely through stereo speakers in the monitor and some of the exclusives there make better use of the stereo effect (the pack in Burnin' Rubber game pans the car engine sounds depending on how you pass them for example).

I wasn't really hoping for any specific result, although I admit I am a bit surprised that no one here uses stereo at all. I just made the poll to find out what people use and see if there's any point in doing games with stereo sound. Looks like I got my answer.

I have a stereo module from Ben for a +3 (single AY, just rerouting the output channels). Just have not got around to fitting it yet...

I have a stereo AY system for a ZX81 (two AY chips).

Mark

I also have one of Ben's stereo mods fitted to my +3. The output goes into a line mixer which can be toggled between mono and stereo. One day I may get around to adding an ABC/ACB switch, too.