all right....I have not used KDE which is the normal desktop for Kubuntu in years. Can you confirm if Phonon is installed.

post the output to
If and only if you see hits for phonon....this next link may help
https://userbase.kde.org/Phonon

2) For now, leave the hdmi cables out until you have a chance to report if hardware keys can interact with your Xorg settings to do a dual monitor setup. Also.....it make it easier to trouble shoot I prefer we fix one issue in case you are right and the hdmi interfers with your aplay settings.

3) Now let me re-visit your aplay list in English from alsa info
Now your alsa info link shows that
but that is not helpful to a new linux Alsa user. its the aplay device information above that matters.

Let me explain it in umm windows terms.
you have one card .....alsa counts cards from zero

you have 6 devices ....alsa counts devices from zero
but the only analog device is device 0.

It is possible for the pins to need a re-configure but for now take a screenshot of the following command
upload it to a host site....I use ingur.com and then link to it.

EDIT we need -c0 because without it....alsamixer returns only one or two controls that PA has control over which is not helpful at all.

I will show mine as example
https://imgur.com/EKL2V6D

you may notice I have no control to enable or disable "auto mute"
b) that if headphones were inserted....they are muted and no volume set
c) to unmute them....I would use the keyboard arrow key (->) to get to that control
---press m key to unmute....if I press m a second time it mutes
---then press page up or up arrow to raise volumes

the mixer levels are initially controlled at boot up by the mixer level file at /var/lib/alsa called asound.state

so show us yours by
it is pointless saving mixer levels with headphones unmuted and volumes set unless we keep TWO mixer levels
but that will require another command to reset from mixer level one to level two
AND it is easier to use pavucontrol to change mixer levels for a linux newbie.

2 members found this post helpful.

Next.....this next bit can be confusing so alsa can use a system wide config called
/etc/asound.conf
but it is better for you with your devices we create a home config file called

.asoundrc.....NOTE the dot makes it a hidden file. Not sure if you already have any so show the output to
Lets assume you have none....because of Pulseaudio (=PA)

so we create one by copy and paste into a terminal as a normal user.
pwd should show /home/<your-login-name>

when you run
you should see similar screenshot to this
https://imgur.com/3paN2tT

now do a full reboot.....and redo this command
and report if you still see HDMI or analog (PCH)

2 members found this post helpful.

Got some hits but I didn't found any tip that sounded related to my issues.


Agree, it is better to tackle one thing at the time.

I see, now things are becoming more clear.

I did run the alsamixer with the arguments you recommended and I took two screenshots: one without the headphone and one with it plugged. I noticed that the alsamixer did the auto unmute thing and setted the headphone volume automatically as well.

Here's the gallery with both screens.

This command didn't found such file. I did a ls at the directory and it is indeed empty.

Hi

Your mic (called capture in screenshot) is active with raised volumes. As laptops have inbuilt mic I suggest you go back into the alsamixer command you used for screenshot then retest.

But the .asoundrc....post 17 is more important

Right arrow to mic...press SpaceBar to disable and retest

2 members found this post helpful.

Yes, no asound.conf on /etc/.

I created the .asoundrc inside /home/myuser/ with the code you posted, rebooted and it still shows both codecs as before:

But somethings changed, but for the worse: now there is no sound whatsoever. The speakers are mute, same as the headphones, and if I try to run alsamixer on Terminal, I get a bunch of errors as this screen shows.

Other thing I've noticed is that the KDE sound widget shows the volume at 100% in a "ficticious output" (this is the literal translation from "saída fictícia" as shown to me here). The sound related function keys - mute, sound down and sound up - stopped working as well.

right there may be corruption in your .asoundrc file.

I need you to post the full output of
due to image that claims .asoundrc may be old or corrupted.

I have the same file....and speaker-test works for me.....and does alsamixer -c0

2 members found this post helpful.

As follows:

Here's a screenshot.

YIKES!!!

use your text editor to delete this part of last line reboot and redo the codec command please, and alsamixer command

and from the top line

that corrupt file would occur if you copy and paste into a text editor,
but I asked you to do it into a terminal.

LOL

2 members found this post helpful.

let me reveal what you should see again please.

2 members found this post helpful.

Sorry, I got confused about creating the file on the Terminal itself and thought it would be a good idea to check things out with nano. In the end, I pasted everything and didn't payed enough attention.

Now everything seems to be right about the .asoundrc file.

But the situation is the same:

- no sound over speakers and headphones
- sound related function keys are caput
- alsamixer won't work
- it still lists both codecs

Here's the screenshot.

Took out the . Sorry again.

Now, things improved:

- speaker sound is back
- function keys are working
- alsamixer runs

What isn't right:

- it still lists both codecs
- headphone sound remains very low and distorted

Pics of both alsamixer and commands outputs.

EDIT see below
In last image....speaker volume of zero shows "auto mute" is working correctly to mute speakers and give some volume to headphones.

I am guessing you have raised headphone volume to max as you can not hear them?


.
Has that changed?

in post 19 I asked you to mute the capture device which is mic (input).
Lets see if we can eliminate mic feedback as causing distortion?

I would have liked to show you an alsa config for your model ALC256 but according to link
https://chromium.googlesource.com/ch...dio-Models.txt

I can not spot any alc256 reference.

2 members found this post helpful.

OK we have attempted to force alsa to use the correct card number (zero) and the correct device number (zero)

can you now use your menu to search for either pulseaudio volume control or
pavucontrol....if not not found...run command

then open that new app....this is PA graphical mixer control

go to the tab for configuration....for the built in audio
Pull down the profile and choose Analog Stereo Duplex.

take a screenshot if you have any problems please.

It will be bed time for me soon

2 members found this post helpful.

YIKES forget post 27....I have just confirmed on my system I get HDMI codec too.

cat /proc/asound/card0/codec* | grep Codec
Codec: Realtek ALC887-VD
Codec: Intel Kabylake HDMI

different sound device but same CPU.

therefore we need to see if PA can fix

2 members found this post helpful.

The mic on mute didn't made any difference. It still sounds very low and distorted.

Done as you suggested, but everything remains the same: speakers sound great, headphones works through USB-C dongle, but not from the headphone jack.

pavucontrol related pics.

I can't thank you enough for your time, patience and help!