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Ubuntu gives a strange hissing sound when PC is on idle. Headphones are plugged in too and both headphones and speakers are working.

The hissing sound comes when my PC is on idle and no sound is being played. When any sort of sound plays, the hissing sound goes away, while it returns when playback stops.

Tried unplugging headphones and using speakers alone. Still not fixed.

There is no such hissing on headphones and there is NO PROBLEM with the speakers since they work fine on Windows.

So the sound card is a Realtek ALC887-VD Generic one and the speaker is a Philips SPA9080B connected to the PC via rear motherboard generic output.

One more thing, the only other time I hear such a sound is when my PC is turned off but the speakers aren't. So my best guess is that MAYBE Ubuntu is kind of cutting off connection to the rear ports when PC is idle? MAYBE related power-saving?

Volker Siegel
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Rishikant
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  • Without knowing your soundcard/setup, my first suggestion is to pluck the speaker jack in the headphone port and the other way. does the 'hiss' is moving to the headphones? Than I would open a terminal and use alsamixer (maybe it need to be installed via sudo apt install alsamixer) and take a look at the slider. use cursor left/right to select a slider and up/down to change the volume. Of there is a button below, also try m to mute. ... Maybe windows does not use 100% volume or is muting the channel, when there is no output. At first we need to find the control, than we find a solution. – LupusE Sep 15 '20 at 13:21
  • Connected speaker jack to front headphone port and vice-versa. Still the hissing. And NO, there is no hissing in the headphones when connected to rear jack. Even when Windows volume is on 100%, there no hissing and further, Windows is not muting anything at all. There is no problem with Windows as well as the speakers. – Rishikant Sep 15 '20 at 14:56
  • Your suggestion regarding power saving may be correct. So please try this solution to turn off power saving: https://askubuntu.com/questions/1230833/annoying-click-popping-sound-on-ubuntu-20-04 – raj Sep 15 '20 at 15:08
  • Turns out we were going in the right direction! The issue was related to power saving. Unfortunately, the link you shared was for Intel Audio. Mine is Realtek. After a bit for looking around, commented out the line "load-module module-suspend-on-idle" in /etc/pulse/defualt.pa and restarted pulseaudio. Viola ! Issue fixed. Thanks for the help ! – Rishikant Sep 15 '20 at 15:13
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    @Nmath Done. I am new to this forum so didn't think about it. – Rishikant Sep 15 '20 at 15:45

2 Answers2

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Okay so as guessed, the issue turned out to be because of power saving, where pulse audio muted the playback devices which were idle. Now since the speaker was muted, it started giving out it's usual hissing sound. To fix it,

  1. Open /etc/pulse/default.pa with sudo privileges

  2. Comment out the line : load-module module-suspend-on-idle

  3. Restart pulseaudio with : systemctl restart --user pulseaudio

Rishikant
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I have the same issue after the TLP module being installed. The cause is that TLP, by default, disables the power-saving mode of the speaker when AC is plugged. And in TLPUI, I changed the value to 1, which means to enable the power-saving mode when using AC. Then the hissing sound is off automatically and I have the TLP module working as well.

Hope this also helps.

Salom
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