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+--- Thread: Inverted speaker stereo polarity (/showthread.php?tid=9555)
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Inverted speaker stereo polarity - slyecho - 04-01-2020
Hi,
I've been using my Pinebook Pro since January and one of the first things I notices about the speakers is that one of the speakers is in reverse polarity from the other.
This results in audio that sounds very weird with almost a kind of a fake "surround" effect.
Here is one video that you can play to verify this situation yourself.
https://www.youtube.com/watch?v=kUT6ZhFdLkA
This only appears on the speakers, not the headphones. I also tried to look if it is easy to reverse the cables but it's unfortunately not and the cables are very thin and I'm not confident enough of my soldering to hack it in hardware.
One way to fix it in software is to use alsamixer and then enable either "R invert" or "L invert", however, now the headphones have incorrect audio.
I'm curious if your Pinebook Pro has similar issues and how did you solve them. I will probably try to hack it on the hardware level at some time in the future.
RE: Inverted speaker stereo polarity - Arwen - 04-01-2020
(04-01-2020, 06:26 AM)slyecho Wrote: Hi,
I've been using my Pinebook Pro since January and one of the first things I notices about the speakers is that one of the speakers is in reverse polarity from the other.
This results in audio that sounds very weird with almost a kind of a fake "surround" effect.
Here is one video that you can play to verify this situation yourself.
https://www.youtube.com/watch?v=kUT6ZhFdLkA
This only appears on the speakers, not the headphones. I also tried to look if it is easy to reverse the cables but it's unfortunately not and the cables are very thin and I'm not confident enough of my soldering to hack it in hardware.
One way to fix it in software is to use alsamixer and then enable either "R invert" or "L invert", however, now the headphones have incorrect audio.
I'm curious if your Pinebook Pro has similar issues and how did you solve them. I will probably try to hack it on the hardware level at some time in the future.
Thank you for the clear description of the problem, and the 2 solutions. (Even though you have not implemented the actual re-wiring...).
I've updated the Pinebook Pro's Wiki, trouble shooting section below with this information:
Wiki - Pinebook Pro - Sound issues
As usual, feel free to correct, improve or comment, (good or politely bad).
RE: Inverted speaker stereo polarity - slyecho - 04-04-2020
Thanks, I was just curious if others have come across this.
RE: Inverted speaker stereo polarity - Dendrocalamus64 - 04-04-2020
https://www.youtube.com/watch?v=Oinqd_MYO6U
Sounds like my ANSI PBP from the last batch has this too.
RE: Inverted speaker stereo polarity - xmixahlx - 04-07-2020
the audio setup of my pbp is correct. i follow the latest kernel and alsa state from manjaro git. if you are on the latest manjaro it is probably correct for you, too.
RE: Inverted speaker stereo polarity - manawyrm - 04-09-2020
Yes, the issue with the playback polarity of the speakers is well known.
Manjaro has a special handler that will change the polarity when switching from headphones to speakers:
https://gitlab.manjaro.org/tsys/hpdet-pinebookpro/-/blob/master/audio_jack_plugged_in.sh
(which is why @xmixahlx reports that it works for them)
RE: Inverted speaker stereo polarity - slyecho - 04-10-2020
OP here, I forgot to mention that I also have the ANSI version and that I'm running Manjaro too.
I have the community package pinebookpro-audio installed that is referencing the same Gitlab URL, howver there are no polarity commands in my system.
It seems to be an older version of the package.
So I cloned and installed it manually and the switching works now when I plug in headphones.
RE: Inverted speaker stereo polarity - manawyrm - 04-13-2020
(04-10-2020, 10:17 AM)slyecho Wrote: I have the community package pinebookpro-audio installed
Oops, sorry about that. I've asked the maintainer of that package to build a new version with the inversion fix included.
Thanks for the info, it should be fixed for everyone soon
RE: Inverted speaker stereo polarity - zaius - 04-14-2020
(04-13-2020, 05:43 AM)manawyrm Wrote:(04-10-2020, 10:17 AM)slyecho Wrote: I have the community package pinebookpro-audio installed
Oops, sorry about that. I've asked the maintainer of that package to build a new version with the inversion fix included.
Thanks for the info, it should be fixed for everyone soon
Thanks
Although what happens if Pine fixes the hardware? I don't see how the OS could know how the speakers are wired, so then the user would have to toggle it if they got a new fixed PBP or fixed it themselves.
RE: Inverted speaker stereo polarity - Der Geist der Maschine - 04-14-2020
(04-14-2020, 11:53 AM)zaius Wrote:(04-13-2020, 05:43 AM)manawyrm Wrote:(04-10-2020, 10:17 AM)slyecho Wrote: I have the community package pinebookpro-audio installed
Oops, sorry about that. I've asked the maintainer of that package to build a new version with the inversion fix included.
Thanks for the info, it should be fixed for everyone soon
Thanks
Although what happens if Pine fixes the hardware? I don't see how the OS could know how the speakers are wired, so then the user would have to toggle it if they got a new fixed PBP or fixed it themselves.
The current script could check for the existence of a file which users of new pinebook pros would need to touch. Perhaps users of a new Pinebook Pro will be asked not to install that package in the first place.
It would not surprise me if information in /var/lib/alsa/asound.state is enough, though.
There is not much to worry.