Sending an inaudible noise to SPDI/F Optical output

Hello community :slight_smile:

In the past, I’ve founded a little trick that enable a permanently inaudible audio signal to the optical spdi/f output. In my configuration I use an optical to a 5.1 logitech Z5500 system.
But the system always shut down the transmission data after a few second… This can be annoying for all the systems sounds etc, but mainly some games I have will start without any sound…

(A bug in Pipewire ? Or other ?)

Problem is, I cannot find again this little trick to do…
Is anybody here using the same system and had any idea to recreate this again ?

Many many thanks !

I know what you mean. I’ve experienced this more notably when using external speakers, like a soundbar. For example, when performing a speaker test using the Test feature, the first test, possibly even the second, won’t be audible at all! Eventually sound kicks in and we’re good.

image

For the most part I’ve put it down to a quirk of the external speakers, and some will indeed go into standby if the audio is silent for a period of time. However I can also confirm that even with analogue headphones on a completely different system, there is a very slight cutoff from the beginning of the first test. Instead of “front left” it sounds more like “…ront left”.

I wonder if this might be related?
Arch Wiki > Pipewire > Noticeable audio delay or audible pop/crack when starting playback

Hi. I think you mean this:

Some devices implement their own detection of silence and suspension. For them disabling node suspention alone won’t work. It’s possible to work around them by adding a small amount of noise, making it so the output never goes fully silent:

See the link posted by @Bink above for details.

Hello :slight_smile:
I will try both methods and keep you informed :wink:
Thanks !

Hello everybody !
Good and bad news…

The good news is : Firt method described on the Arch-Wiki seems to work ! No more ‘cutted’ sound.
The bad news is … Now I don’t have any sound on any games via Lutris. (Steam is not impacted) I see my soundcard switching from Starphip/Matisse 5.1 to Digital Stereo, and then back to Starship/Matisse 5.1, My logitech detect a stream (Dolby Digital) But no sound at all…

Tryied with wine-ge & umu-launcher, same problem. Can’t understand…

Any idea ?

Maybe lib32-pipewire and lib32-libpipewire are missing ?

True,
Thooses was not installed. (Is this normal ?)

Unfortunately, no changes. Still have no sound at any games.

Mistake of my part too : The only game has working sound is WreckFest (on steam), any other titles, even on steam, has no sound at all…

They might be required for proton / wine and such. Have you installed them now and performed a reboot ?

I have tried to disable the auto suspension via wireplumber as well, but I’m not really certain if it works at the moment. In my case it’s a different issue, as I’m connected via line out to an stereo amp and I’ve got line noise in case there is no audio signal. I can’t really tell if the dropin conf file is applied and in use.

Wasn’t aware that the services are running in user space and that they had to be restarted with --user explicitly.
According to pactl info it should work. Only issue is that I don’t find any documentation about the dither methods and didn’t pursued that further yet.

Steam audio works just fine after the changes. At least for the one game I tested.

Hello !
Yes, installed, rebooted.
Nothing changed. Impossible to get any sound on my games.

all I can tell you is, when you launch a game, you can see little banner 1st swith to Digital Stereo ( Why ?) And then back ton SPDIF Starship/Matisse 5.1 sound.
The controller of my Logitech 5.1 detect a stream input, but this stream input seems to be “blank”

All other system sound working fine.
Even if I put a movie with 5.1 DD bitstream.
BUT : Only if I let it WITHOUT SPDIF Audio Passtrough !
If I check this box > Black Screen, and no more sound.

In my opinion the problem is here : With the Spdif passtrough. But, where ? And Why ?

I hope you can help me more :slight_smile:

Best regards.

Sadly I can’t give you helpful insights about SPDIF audio passthrough, as I don’t have any optical ports on my machine. My whole audio setup consists currently on plain old stereo via the analog line out to an external amplifier.

You have other options to connect that Logitech 5.1 surround system. Besides the SPDIF input it provides digital coax as well as an analog 5.1 input. Have you tried one of these instead ? Furthermore, is there even an IEC958 output listed in your sound settings ( that should be the SPDIF output) ? Maybe this thread helps, the user was able to get SPDIF output by using the stereo duplex profile instead of pro audio by using alsamixer.

Don’t see it mentioned here, unless I missed it, but have you already tried resetting your Pipewire config?

Do a full system update, then rename the following folder and reboot. It may or may not work, but it’s worth a shot.

mv .local/state/wireplumber .local/state/wireplumber-bkp

OMG friends, I’ve found it !
With all settings by default, The audio output from the video card is activated too, I’ve always deactivated it in the past, with no problems.
Don’t ask me why, but this time, it’s not working anymore.

If I let the default basic settings, just select my internal audio card as default, when I launch any game, now it’s switching to TU106 SPDIF HDMI for a second, then back to my Starship/Matisse internal audio 5.1 settings.

Don’t ask me why, I’absolutely don’t know :grin: But it’s working back !
Probably another bug with this stupid nvidia card again …
Anyway, again this community helped me a lot ! Many many thanks for all of you !
Have a nice sunday :slight_smile:

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