# Possible alsa error?

**URL:** <https://www.ruby-forum.com/t/possible-alsa-error/231019>\
**Category:** GNU Radio\
**Created:** [July 17, 2014, 4:29pm UTC](https://www.ruby-forum.com/t/possible-alsa-error/231019 "2014-07-17T16:29:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [July 17, 2014, 4:29pm UTC](https://www.ruby-forum.com/t/possible-alsa-error/231019/1 "2014-07-17T16:29:17Z")

</div>

Hello,

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  
Block paths:  
/home/drdc/target/share/gnuradio/grc/blocks  
/home/drdc/.grc\_gnuradio  
Loading: “/home/drdc/Documents/8 ip switch test.grc”

> > >

Done  
Showing: “/home/drdc/Documents/8 ip switch test.grc”  
Generating: “/home/drdc/Documents/InputSwitchTest.py”  
Generating: “/home/drdc/Documents/InputSwitchTest.py”  
Executing: “/home/drdc/Documents/InputSwitchTest.py”  
Using Volk machine: avx\_32\_mmx

> > >

Done

After the flowgraph is restarted I get the error message that can be  
seen  
in the attached screen shot.

Some background:  
To get the USB sound card to work at all I have