io4 pipewire Arch 16 vs 24 2-ch vs 4-ch help understanding?

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chrisco23
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Joined: Sun Feb 28, 2021 10:43 pm

io4 pipewire Arch 16 vs 24 2-ch vs 4-ch help understanding?

Post by chrisco23 »

I have a bit of a Frankenstein setup that is in fact working but it feels kludgy, requires small changes to qpwgraph every run, and I'm hoping someone can enlighten me some as to exactly how and why it is working the way it is, and how I might be able to make it a little more sane.

For now, I just want to understand the basics, so even though yes I will be later doing music with probably zrythm, possibly qtractor, I have this scenario:

Arch Linux
pipewire + wireplumber
Alesis io4

https://paste.pics/L90KR
https://paste.pics/L90LC

For this example, I'm just watching a youtube chess video. I expect 2 channels out, then I'd like to have my io4 interface send 2 channels to my stereo amplifier (HK 3385, use it for all audio always), but also the same 2 channels to a pair of Edifier bookshelves that sit on my desk.

The main amp sends audio out to 2 floorstanding speakers. I bought the Edifiers partly because the treble on the floorstandings are borderline broken, but the bookshelves give me more options in my studio. I control the amp and the Edifiers with 2 separate remote controls.

Now if you're still with me, you can see in the pic of qpwgraph the strange wiring I've been doing, but when I start qpwgraph, it shows 4 outputs coming from Chromium, going in to the io4 (No idea why it says "surround", not trying for surround, just 4 speakers). I then draw the connect lines as shown to get the desired effect. EVERY time I start qpwgraph, or pause then start playing again, Chromium for more than say, a minute.

Questions:

  1. Would there be a way to just save the weird-frankenstein connections? (not just the graph, which saves the components but not their connections as shown). Ideally then this would start every time I run qpwgraph, even every time I boot the laptop.

  2. I only found this out today: There is a switch on the back of the io4 for 16-bit or 24-bit. It's always been on 16. When I put it to 24, suddenly I see only 2 channels going out from Chromium and into the io4 (and no more "Surround", only "Analog"). This I can kind of grok, the part about 2 channels. I've only really been picturing 2 channels all along, but going to 4 speakers. Should I be using this 24-bit switch? But if so, how can I still get the outs (L/R) to my 4 speakers? I don't know if I should be thinking about changes within qpwgraph? with the io4? both??

I know it's a weird setup so thanks for wading through me trying my best to explain it.

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