systemsettings does not play sound when speakers are tested

[Juergen Scholz]

Steps to reproduce:
1. Open systemsettings
2. Change to multi media pane
3. Click hardware setup
4. Select audio device (internal audio for me)
5. Click "Front left" or "Front right" to test speaker/output

Expected:
The test sounds are played

What is actually happening:
No sound is put out; stdout shows a PCM error.
Amarok and others can output sound via pulseaudio

This is the console output of systemsettings with the last three lines being the output a click on any of the test buttons gives:
"/home/juergen/.config/kde.org/libphonon.conf"
libpaths ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/usr/bin")
void BackendSelection::load() "/usr/bin/phonon4qt5_backend" does not exist
qooooooooo
"/home/juergen/.config/kde.org/libphonon.conf"
libpaths ("/usr/lib/x86_64-linux-gnu/qt5/plugins", "/usr/bin")
void BackendSelection::load() "/usr/bin/phonon4qt5_backend" does not exist
qooooooooo
qooooooooo
context_state_callback "Terminated"
context_state_callback "Terminated"
context_state_callback "Terminated"
Doing update 0
Got info about card "Tahiti XT HDMI Audio [Radeon HD 7970 Series]"
Doing update 0
Got info about card "Internes Audio"
Got info about sink "Tahiti XT HDMI Audio [Radeon HD 7970 Series] Digital Stereo (HDMI)"
Got info about sink "Internes Audio Analog Stereo"
"Want ID: No; Have ID: No"
"Want ID: No; Have ID: No"
"Updating ports for device 'Tahiti XT HDMI Audio [Radeon HD 7970 Series] Digital Stereo (HDMI)' (1 ports available)"
Doing update 0
"Updating ports for device 'Tahiti XT HDMI Audio [Radeon HD 7970 Series] Digital Stereo (HDMI)' (1 ports available)"
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM 0
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM 0
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM 0

~> lsb_release -rd
Description: Ubuntu Xenial Xerus (development branch)
Release: 16.04

~> apt-cache policy systemsettings
systemsettings:
  Installiert: 4:5.5.4-0ubuntu1
  Installationskandidat: 4:5.5.4-0ubuntu1
  Versionstabelle:
 *** 4:5.5.4-0ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
        100 /var/lib/dpkg/status