Quoting: NonjuffoI think this write-up explains the realities of digital audio playback much better than I can.

Yes, I've read that before actually.

I noticed that SPDIF outputs are shown without volume bars in ALSA mixer. Does it mean that software volume control (like in KDE) will have no effect on such setup, and using the hardware volume dial on the amplifier is the expected method? I.e. SPDIF is supposed to be just a pure signal, and the rest handled by external hardware? Or PulseAudio volume control will still have an effect on it?

Last edited by Shmerl on 9 December 2019 at 3:57 am UTC

I can’t check right this second, but I’m sure Pulse lets you adjust the volume of digital signals. I know for a fact that I can adjust the volume of audio sent via HDMI. This isn’t possible on e.g. my Mac, which forces me to use the monitor’s controls and that’s less than ideal.

You can adjust SPDIF output volume with pulseaudio controls, but pulse often seems to bundle the volume settings in unintuitive ways. For me its easier to just set SPDIF out to 100% and use application/amplifier controls instead. You can test yourself with pavucontrol what the controls actually do. You don't even need to connect anything (unless you actually want to hear something).

Setting player/SPDIF less than 100% means you start losing detail depending on the material. There is a limited number of bits after all (unless you pad with larger bit depth). I don't know if pulse forces some additional signal processing, but this should be the "purest" setup.

Just got my DAC and amplifier, and set them up over optical SPDIF from the motherboard output on the back. The sound is very clean! JDS Labs did a good job with it. Even on max amplification - there is no noise.

Last edited by Shmerl on 12 December 2019 at 11:37 pm UTC

Is there any tool that visualizes current audio output in Pulse or ALSA?

ProjectM? ..or what you mean exactly by that

I mean something similar to how Audacity displays audio graph.

Last edited by Shmerl on 19 December 2019 at 6:38 pm UTC

GLava, cli-visualizer, cava, spek, spectrum3D etc

some links also:

https://github.com/karlstav/cava
https://github.com/dpayne/cli-visualizer
http://spek.cc
https://github.com/jarcode-foss/glava


edit: ohh wait, you mean just the peaks of left and right channel?
that i dunno if there are any.

Last edited by Xpander on 19 December 2019 at 8:04 pm UTC

I mean simply the waveform graph: https://en.wikipedia.org/wiki/Waveform

That's what Audacity displays for audio by default:



Realtime audio visualizer can display it by storing some amount of history of what was played before I suppose.

Last edited by Shmerl on 19 December 2019 at 8:30 pm UTC