On Sat, Mar 04, 2023 at 08:27:45PM +0100, Jan Stary wrote: > On Mar 04 18:46:29, [email protected] wrote: > > On Sat, Mar 04, 2023 at 06:21:08PM +0100, Jan Stary wrote: > > > > I have two devices around here. Let's call one devA and one devB. > > > > devB is my main OpenBSD workstation devA is some kind of gaming device > > > > which has a normal 2 channel audio jack. I want to connect the line out > > > > connector of devA to the line-in of devB and listen to both devices > > > > with my headphone amplifier connected to out/spdif of devB. > > > > > > Why do you want that? I mean, what are the two simultaneous things > > > you want to listen to, one comming from your game console and one > > > from your workstation? > > > Mostly it's running an audio player, a voip application or video player > > on my workstation while playing on the other device. > > That' what confuses me: you want to listen to the game play, > while simultaneously playing some other music? Yes. Or watching videos or voice chatting about the game with other players.
> > > > In analog mode this works beside the poor quality of the mainboard > > > > which seems to generate a lot of noise. > > > > > > That's not poor quality of the mainboard, > > > that's an electronic device suffering a _lot_ > > > of interference from the electronics jungle around it. > > Isn't the board shielded inside it's case? (metal) Around the metal case > > there is also a small rack where the only other component running is a > > small switch? My guess would have been that the case and the rack should > > shield the internal components so the inteference must be coming from > > the board itself? > > That's not the problem. > The on-board audio device gets interference > from all the other electronics _inside_ the case. > > > If that's not the case, is there something I can do to > > improve the situation? > > Use an USB audio card that doesn;t have to live inside the case. > > > I've often read about audio components on > > mainboards being badly shielded from other components so assumed it > > maybe coming from those. Could a dedicated sound card maybe fix that, > > provided it got better shielding? > > It will never be shielded enough; > inside the case, it will always get a lot of noise. > > > > > When switching to SPDIF the noise is gone > > > > > > Yes: the digital signal does not suffer from the analog noise. > > Of course, bad worded from my side. I wanted to point out that > > nothing, not even noise from devA out is coming with that signal. > > > > > > Does you headphone amplifier take the spdif output of your workstation? > > > (What headphone amplifier is that?) > > The headphone amplifier is a beyerdynamic A20 which takes two analog RCA > > inputs. > > So the headphine amplifier cannot take any spdif input, > having only analog inputs. > > > I was a bit testing and had a 24bit/192khz DAC laying > > around and put it in between > > Meaning, inbetween your workstation and the headphones amplifier. > So there is another device involved which you didn't even mention. Yes but it just takes the stream from spdif and converts it to analog stereo out. A headphone amplifier or any other stereo device with spdif would just do the same. I just double checked with some active speakers with direct spdif input, same result. > > with a very short RCA cable to get rid of > > that noise. > > The cable is hardly the problem. > > > Not ideal but worked as the digital signal of course not > > suffers from analog noise and the analog part is only 0.3m long now. > > So the analiog output of your gaming console > gets converted to digital by your onboard audio chip, > mixed with what the workstation itself plays (you are > running sndiod I suppoes), and that mix is sent out as spdif Yes running sndiod. > to another DAC, which converts it to analog > and sends it to your headphones amplifier. > (Except the game sound is lost somewhere along the way.) > > That seems a bot convoluted to me. Because of the noise it got I think. The initial idea was to use the analog output of the gaming console, take it from the line-in of my onboard audio chip, convert it, mix it with the normal output and send it out via analog out. Which is not really working out because of horrible noise with the onboard audio chip. While the setup is working in analog mode, besides the noise, and all other devices are getting normal/correct inputs and outputs, the issue seems somewhere in the mixing step. I think I will just go with that external card solution. But would be interesting to know if someone is actually mixing line-in and sending it out via spdif with sndiod. nebulo
