Handling (mixing) external card audio?

[m00dawg]

In talking about changing the card pins in this thread , I wonder if there could be a solve for being able to mix audio in some way. There's multiple folks thinking about sound cards. I myself will be pretty over the moon with the native solution available in the X16. Nonetheless, while I was thinking about sound card examples, I thought about something like a GUS solution (which, to refresh memories, it was a sound card that has it's own RAM and had hardware accelerated sample playback). In that context, an application would just tell the card to play sample X (optionally at frequency or note Y).

Anyways point is, whatever sound cards folks come up with, the issue of how to mix the audio comes up. On the MB6582 (the 8-SID monster MidiBox), there's a passive mixer that mixes all 8 sids into a single stereo output. That design is a bit attenuated but it works and seems inexpensive (assuming there is space on the board for a few resistors and traces). Wondering if perhaps using 2 pins on the card slots for stereo audio would be nice? Although a cheaper solution might be to just have an "external audio" pin header on the board (which one could optionally jumper to ground to avoid noise), kind of like the CD audio connectors of yore.

Ramblings aside, having a means to mix audio from sound cards with the internal audio of the computer would be a nice to have. Certainly not a need to have but could avoid user headaches and enable musicians and app devs alike to get the most use of all the hardware without having to require any external mixers and things.

Given the X16 itself, as of the current proposal, will have 26 channels total (16 PSG, 8 FM, 2 DPCM) - the need for external sound solutions is perhaps lessened to a degree, but while I'm all about the chiptunes, I have a feeling the draw for an efficient DPCM card/sampler will be compelling for some. Plus the folks that really want a true SID sound, etc.

[BruceMcF]

50 minutes ago, m00dawg said:

In talking about changing the card pins in this thread , I wonder if there could be a solve for being able to mix audio in some way. There's multiple folks thinking about sound cards. I myself will be pretty over the moon with the native solution available in the X16. Nonetheless, while I was thinking about sound card examples, I thought about something like a GUS solution (which, to refresh memories, it was a sound card that has it's own RAM and had hardware accelerated sample playback). In that context, an application would just tell the card to play sample X (optionally at frequency or note Y).



Anyways point is, whatever sound cards folks come up with, the issue of how to mix the audio comes up. On the MB6582 (the 8-SID monster MidiBox), there's a passive mixer that mixes all 8 sids into a single stereo output. That design is a bit attenuated but it works and seems inexpensive (assuming there is space on the board for a few resistors and traces). Wondering if perhaps using 2 pins on the card slots for stereo audio would be nice? Although a cheaper solution might be to just have an "external audio" pin header on the board (which one could optionally jumper to ground to avoid noise), kind of like the CD audio connectors of yore.



Ramblings aside, having a means to mix audio from sound cards with the internal audio of the computer would be a nice to have. Certainly not a need to have but could avoid user headaches and enable musicians and app devs alike to get the most use of all the hardware without having to require any external mixers and things.



Given the X16 itself, as of the current proposal, will have 26 channels total (16 PSG, 8 FM, 2 DPCM) - the need for external sound solutions is perhaps lessened to a degree, but while I'm all about the chiptunes, I have a feeling the draw for an efficient DPCM card/sampler will be compelling for some. Plus the folks that really want a true SID sound, etc.

If you mean distinct from the BUS_L and BUS_R lines ... I think a pin block header would be the most practical approach for not bumping the build cost up very much.

[m00dawg]

1 minute ago, BruceMcF said:

If you mean distinct from the BUS_L and BUS_R lines ... I think a pin block header would be the most practical approach for not bumping the build cost up very much.

Yep I think you're right. Does mean more external parts for mixing more than one sound card but I think that would be pretty rare scenario and, if I'm wrong, that's a solveable problem by way of a passive mixer that then plugs into the single L/R input.

Given the buzz around sound cards (hah forgive the accidental pun) a header would be a great addition I think.