I've really done it this time. I'm running Debian Stretch Testing, Kernel v. 4.3.0-1-amd64. With X Server I use the LXDE desktop environment.
I had been using pulseaudio without any trouble. I tried to install audacity v. 2.1.2. I compiled it from source, but when I open audacity, it doesn't read any audio input or output sources. If I try to open a file and play it back, it says, 'Error while opening sound device. Please check the playback device settings and the project sample rate.' The playback device setting drop-down menu is greyed out, however, as is the input device setting. Incidentally, I have audacity installed on a Windows 10 virtual machine (VBox), and it works fine, but I need audacity on the host machine as well. Frustrated with this, I attempted a possible fix of using 'pavususpender'. This did not help at all. I then attempted to download Ardour, as an alternative to audacity, compile it from source, and install it. I was lacking several package dependencies, however, so I began installing them through the apt package manager: boost library, pkg-config, glib-2.0, glibmm-2.4, sndfile, liblo, taglib, vamp-sdk, vamp-hostsdk, rubberband, and clang. I installed the -dev version of all these packages where applicable. I still haven't been able to complete the installation of Ardour, for reasons which are not the object of this inquiry. Now pulseaudio won't work at all, in addition to several other programs. Issuing 'pulseaudio' returns 'pid.c: Daemon already running; main.c: pa_pid_file_create() failed.' however if I issue 'pavucontrol', a dialog box flashes for an instant and then disappears, and the volume control gui tool never opens. The volume control keyboard shortcuts still work (I still have sound), but they must be going through alsa. Even more inexplicably, the same thing happens if I try to open up a pdf file with evince, and when I try to use the firefox browser. A dialog box flashes for an instant, but the program never opens. The screenshot accessory has also stopped working. Chromium-based browsers are still working just fine, however, and for viewing pdf files I can still use Master PDF Editor 3. These are all the previously fully functional programs which have stopped functioning since this debacle that have so far come to my attention. Having audacity working would be a nice luxury, but now my first priority is getting firefox going again, since there are some web-based tasks I must perform on a regular basis which do not work properly in chromium browsers. Thanks in advance for any light you may shed upon me in my state of ignorance. Levi
