Testing speakers with bluetooth HSP/HFP profile.
When I connect a bluetooth headset, set it as default sound output and set it to HSP/HFP profile, then click test button and click 'Mono' button in the appearing dialog, noise is played. paplay, mplayer and VLC play normal sound, (with deteriorated quality as expected when using HSP/HFP) so this is a testing application issue. Problem exists both with native pulseaudio HSP support and with HFP support via ofono.