(in my opinion the main work should be some kind of alsa-jack-only overlay on devuan, mainly because possibly all the desktop environments and other apps pull either pulseaudio or pipewire and thus cause problems

That in a nutshell, describes @rations' jack-bridge project, a much more complex and encompassing system that I think might do what you are asking. And there's some more nice frontend projects for the alsamixer, saw one that was really nice the other day, it was done in QT which I don't much like, but it was very nice and complete and did split volume controls into right-left channels whereas mine doesn't.

Think of those projects as thoroughbred racehorses that can do it all.

My project, is just a donkey, not too pretty, stubborn at times, but day-in and day-out it just gets the basic jobs done and does them fast as hell for a donkey.

At this point, most anything else I could do would be feature-creep and bloated code. Gonna keep this thing small and simple, there's already other folks working on more sophisticated stuff, i'm going to stick to my little niche and just try to make it the best it can be by little improvements to behavior and some expanded stuff as more testing is done to accommodate more types of soundcards and scenarios.

It can be done in the mixer for sure, and I haven't seen it done or tried it myself but I would think it's absolutely possible in the EQ as well.

Have been experimenting with the eqalizer a bit. Not with Your tool, just with the basics.

alsamixer -D equal will show the sliders of the EQ. Alsamixer provides keystrokes to split a stereo track and adjust the two channels seperately. More or less, here in devuan not all strokes seem to work, but anyway.

On my notebook i am using qasmixer anyway and for a few years.
quasmixer provides a field for user defined devices. Entering "equal" there shows the eualizer controls, and they are working. There does not seem to be a way to split stereo channels, but  channels that have already been split using alsamixer appear split in qasmixer as well, and they are grouped nicely. And the can be operated perfectly from that interface.
Which means that that little and well established program serves 90% of my needs.

So that kind of behavior might be what should be expected for Your little tool as well.

(in my opinion the main work should be some kind of alsa-jack-only overlay on devuan, mainly because possibly all the desktop environments and other apps pull either pulseaudio or pipewire and thus cause problems: after the upgrade to excalibur, my intentionally alsa only machine had pulled pipewire and started the daemon. Which caused audio from freetube not to work. An overlay to devuan might provide dummy packages to resolve those nasty dependencies.

For my current problem with one sided hearing loss that result is really cool: i would just need to run a mono track, adjust the bad side range by range until i hear that frequency range appearing in the center, and i'll end up with a nice overall setting. Being able to enjoy music again is *really* cool.

So I figured out the other bug, wrong command that was a holdover from earlier experiments, so my bad of course. Tickled though that I did figure it out just by looking at the code, didn't have to do any searches or doc-reading and my fix worked the first time with a bonus that I got to eliminate a now un-used function so the script is a little smaller, I think i'm getting better at C.

I'll get it packaged up as 3.1-2 and uploaded here in a bit.
EDIT: All done, it's up now.

Did find a bug though, the new preset-edit window works fine, until you try to move the window and then it leaves a nice trail for you. *sigh*
I've had problems from the get-go with that thing, and mostly seems like yad issues, the version in daedalus is ancient, really could use something newer.
Back to the drawing board.

AlsaTune currently just treats those as a regular slider, but if I set it at 40% in AT, it will in reality fall to 33% on the backend. And when you close then re-open AT the value will now be correct at 33%
Thankfully I only have a couple of these, and on controls I don't ordinarily use.

But another fly-in-the-ointment, some sliders for volume can also be incremental with values other than 1, so they are stepped-channels, just a LOT of steps.

Last fun thing I get to deal with in this adventure of sound with ALSA, is that the backend controls (at least on my test machines) aren't linear even if they read 1 through 100 in the alsamixer TUI, so those numbers will always be off from the AT frontend as I tried to normalize the scale some.

I will go and test the EQ more, the whole thing needs a lot more testing really, it's experimental stuff and needs some people smarter than me to take a look.

Thanks ilargi!

Thanks @fsmithred!

Working on version 3.0-1 now, i've written a little dash/yad script to open an editable text-info window to mod/delete EQ presets in the presets.csv file. Rather than add another button my idea is to take the existing "Save Pre-set" button and change it to "Save/Edit" with a tooltip that explains. So a normal left-click would save a named pre-set as it does now, but a right-click would open the yad window to edit the presets.csv file.

Just noticed: is there any possibility to adjust the EQ for the right and left channel seperately? That would open the possibility to adjust it according to the hearing curves which in my case are really different.

That's a great question! It can be done in the mixer for sure, and I haven't seen it done or tried it myself but I would think it's absolutely possible in the EQ as well.

Unfortunately both are beyond the scope of this simple utility project, at least for the present and forseeable future. Something like that would need it's own branch as I want to keep the main project an uber-simple drop-in base system. But again it's a great question...i'll do some thinking on it, thanks!

Great job!
You may need to make a minor change in the README.txt file for the path to .asoundrc file, so that it reads  /usr/share/alsatune instead of /usr/share/mxeq.

@ilargi
Thank you! And arrrgh, lol, you're right of course...I swear, if I had a dollar for every time I rolled up something and forgot to update all the documentation...seriously, when my wife hears me say i'm about to squash a new Vuu-do iso she always asks if i've updated the release notes.

Will fix that asap. Working on Vuu-do updates this week and i'll get all that sorted too. EDIT: It was bugging me, had another couple spots I hadn't completed the conversion to alsatune as well, so I fixed it and re-packaged and uploaded. Thanks for catching that!!

@Calamity, thank you! There are some nice mixers out there for alsa, just saw a new project somebody did in QT for the mixer and it's really nice and very complete with some features power-users and audiophiles might appreciate.  Mine is a little more simple and pedestrian, but it should get the job done for most folks.

I think the EQ pane could use a show / hide switch akin to Winamp Classic / XMMS interface. And perhaps make the window width resizable, although it's already a very nice and usable project.

ALSA deserves its own graphical mixer!