Volume control for "Analog Surround 4.0 Output" profile is incorrectly balanced.
Hey there maintainers! :)
I'm using a Lenovo ThinkPad X1 Carbon 7th Gen 20QD laptop. This laptop has four built in speakers (technically a Dolby system). When configuring the sound profile to surround 4.0, The audio is great, but the volume control is problematic. Specifically, when using the global volume slider in the GNOME top bar (can't remember its technical name. Tray, maybe?) it appears that moving it around does not affect the speaker volume (which is pinned to maximum), until you reach 0 volume, at which point it mutes. A closer inspection reveals that when sliding to the last 4-5 pixels of the slider, it incrementally reduces the volume until it reaches 0. Playing around with the "Test Speakers" widget reveals that the volume slider correctly controls the "front" speakers (near screen), but not the "rear" speakers (under keyboard, where your wrists would sit). (which, as mentioned, are pinned at max)
Switching to "Analog Surround 2.1 Output" only activates the "front" speakers, and allows correct volume control as expected. It also shows a Subwoofer in the Test Speakers widget, but it seems to be a virtual one, because it just uses the "front" speakers. (There is no subwoofer, and the "front" speakers don't do bass at all. Testing it just generates white noise.)
Switching to "Analog Stereo Output" activates the "rear" and "front" speakers and has the same issue as the 4.0 profile. Interestingly, the Test Speakers widget does not show the "rear" speakers, only the "front" ones.
I've installed Pop!_OS 18.04 and 19.04 on this system over the past week, and experienced the same issue in both. (Pop!_OS is a relatively thin mod over Ubuntu, and uses the same repositories, so it should be the same)
Steps to reproduce:
- Get the laptop model mentioned, another 4.0 or maybe even Dolby Atmos speaker system, or otherwise emulate the configuration.
- Open GNOME Settings
- Change the audio profile to "Analog Surround 4.0 Output" under the Sound tab, for your selected device.
- Open YouTube.
- Play "R U Mine" by Arctic Monkeys.
- Try to play around with the GNOME master volume slider.
Let me know which software versions and log files would help you narrow down the issue. I don't know much about C so i don't think i can directly contribute, but i'm willing to help however else i can.