## “Help! No Volume Mute under Plasma 5!”

One of the subjects I blog about, is a computer I named ‘Plato’, which is running Debian / Stretch (Debian 9), and the desktop manager of which is Plasma 5, which is the successor to KDE 4.x .

One of the features which KDE 4 definitely had, was an icon in the notification-tray, from which we could control our volume levels easily, as well as to mute the sound temporarily, eventually to be unmuted again, at which point the earlier, unmuted settings should be remembered. At first glance it would seem that Plasma 5 has done away with this capability. Trying to solve this can cause people to spend hours searching the Internet, changing their Plasma 5 preferences, and maybe even forgetting their Plasma 5 preferences, because they disabled all their System Sounds from there.

Under Plasma 5, we really only need to have 2 packages installed, in order to control our volume-levels, etc., assuming that we have gotten our hardware recognized first. Those packages would be:

1. ‘plasma-pa’
2. ‘pavucontrol’

The first of these packages integrates with Plasma, and is also responsible for the icon in the notification tray. The second package gives us more control, over our sound-levels specifically, since Plasma 5 uses the Pulse Audio sound-server by default.

If we can see the icon in the notification tray, then a detail which we may overlook after we left-click on that icon, is a tiny little loudspeaker-symbol, on the left end of one of the volume sliders:

Left-clicking on this little symbol will cause the volume-bar to the right of it to become slightly pale, which will mean, that the device in question has been muted. I’m saying that ‘we’ could overlook that we even have this feature, because earlier, ‘I’ did not know that I have this feature.

But, this is only what the ‘plasma-pa’ package can show us. The ‘pavucontrol’ package gives us the ability to fine-tune our sound-levels as shown below:

Now, there’s an aspect to how this setup now works, which is slightly more complicated than how KDE 4 used to handle it. The Pulse Audio server attempts to adjust playback as well as recording levels, on a per-application basis. Thus, the view above is almost empty, because there were no applications playing back any sounds, at the moment I recorded this screen-shot.

A frustrating fact which can exist with this, is that some applications will only play a sound for 2 seconds, during which an additional volume-bar appears in the GUI, and after which that volume-bar disappears again, even if we did not have enough time to adjust one volume level. This happens to result from the design-decision, that volume-control should exist at the per-application level. Hence, even if we use media-control keys on our keyboard, those keys will only affect the one main application which happens to be playing, at any given moment. They won’t affect System Sounds.

But this description might sound like I have to say, ‘There is no problem,’ when in fact, under Debian / Stretch, There Is a problem. That problem, as I see it, lies in the fact that by default, the one volume-bar which the GUI has shown above, for all System Sounds, may not even work.

(Updated 04/26/2018 … )

## Another Reason, for me Not To Set Up JACK as the Back-End For PulseAudio

According to This Posting, I had written that hypothetically, it might make some sense for me to set up ‘JACK‘ as the back-end, by which ‘PulseAudio‘ sends its sound output, full-time. As opposed to the notion not making sense, to allow a few scripts to do so temporarily, that are being run by the ‘QJackCtl‘ GUI.

Well there is still a reason, why this might not be so. Doing so would be consistent, with setting up a Debian system completely according to our own preferences, and then if something does not work, we are up to our own devices to fix it.

My laptop ‘Klystron’ is a Kanotix / Spitfire system, which is also Debian-based, but in which the exact configuration has been done for me, by the Kanotix team, from their Live Disk (which can actually be written onto a USB-Key). This means that there is an advantage to me, in keeping certain configuration details conform to what the Kanotix people prescribed. If I did run into trouble with it, they would have some chance of maybe suggesting solutions, but only on the assumption that mine is still functioning within their parameters.

The way those parameters are, the current back-end to the PulseAudio sound server is displayed in the GUI as being “gstreamer“, and yet good compatibility with all things ALSA is maintained…

If I was to reconfigure my computers completely, for example because I wanted to change them to use the ‘GNOME desktop manager’ for instance, instead of ‘KDE‘, then the Kanotix team would say ‘Sorry, we are not familiar with the details of your system anymore. Therefore, we cannot help you.’

Yet, more generally, Debian allows deep changes to a configuration.

Dirk