I am using an 8 channel USB sound card as an audio source and the first test I do is to ensure that the audio signals can be seen in the attached QT scope block screen shot. This works perfectly when the PC is first started, however when I stop the flow graph and then start it again I get an alsa error message.
When the flow graph is working correctly I get the following message:
<<< Welcome to GNU Radio Companion 3.7.5git-0-g2bb2b314 >>>
Preferences file: /home/drdc/.grc
Loading: "/home/drdc/Documents/8 ip switch test.grc"
Showing: "/home/drdc/Documents/8 ip switch test.grc"
Using Volk machine: avx_32_mmx
After the flowgraph is restarted I get the error message that can be seen in the attached screen shot.
To get the USB sound card to work at all I have