Using external usb soundcard

GNU Radio
1

Hi,

i want to use an external usb sound device. It works without any
problems when playing back music. I dont know how the audio sink block
or gnuradio works with this extern sound device. Howto tell gnuradio to
read all possible sample rate values and use this device ?

Andy

2

Hi Andy,
assuming a modern linux.
In the Audio sink/source, you can enter the device name; potential names
can be found by running
aplay -L

GNU Radio doesn’t know anything about the supported rates of sound
cards; you will need to try that one out beforehand. As far as I know,
ALSA applications also simply try until they get no error.
44.1kHz is universally supported; haven’t met a proper sound card that
couldn’t work with it.

Best regards,
Marcus

3

Hi Marcus,

Hi Andy,
assuming a modern linux.
Ubuntu 14, yes i think this is a modern linux.
In the Audio sink/source, you can enter the device name; potential names
can be found by running
aplay -L

GNU Radio doesn’t know anything about the supported rates of sound
cards; you will need to try that one out beforehand. As far as I know,
ALSA applications also simply try until they get no error.
44.1kHz is universally supported; haven’t met a proper sound card that
couldn’t work with it.
Yes, the “sound” playback works know.

My soundcard support sample rates up to 192khz. So iam asking me how
this sample rate could be set manual or the automatic selected
samplerate could be veryfied. In the audio sink block max. 48khz could
be set.

Best regards,
Marcus
Thank you,
Andy

4

Ubuntu 14, yes i think this is a modern linux.
let’s not start a discussion about favourite linux distros :wink:

My soundcard support sample rates up to 192khz. So iam asking me how
this sample rate could be set manual or the automatic selected
samplerate could be veryfied. In the audio sink block max. 48khz could
be set.

What device name are you using? If you happen to use “” or “default”,
it’s probably the pulse audio server in between you and the ALSA device
making it impossible to use that rate.

Best regards,
Marcus

5

Hi Marcus

My soundcard support sample rates up to 192khz. So iam asking me how
this sample rate could be set manual or the automatic selected
samplerate could be veryfied. In the audio sink block max. 48khz could
be set.

What device name are you using? If you happen to use “” or “default”,
it’s probably the pulse audio server in between you and the ALSA device
making it impossible to use that rate.
i use the device name: front:HD,0

aplay -L:

sysdefault:CARD=HD
AUREON XFIRE8.0 HD, USB Audio
Default Audio Device
front:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
Front speakers
surround40:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer
speakers
iec958:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
Direct sample mixing device
dmix:CARD=HD,DEV=1
AUREON XFIRE8.0 HD, USB Audio #1
Direct sample mixing device
dmix:CARD=HD,DEV=2
AUREON XFIRE8.0 HD, USB Audio #2
Direct sample mixing device
dsnoop:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
Direct sample snooping device
dsnoop:CARD=HD,DEV=1
AUREON XFIRE8.0 HD, USB Audio #1
Direct sample snooping device
dsnoop:CARD=HD,DEV=2
AUREON XFIRE8.0 HD, USB Audio #2
Direct sample snooping device
hw:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
Direct hardware device without any conversions
hw:CARD=HD,DEV=1
AUREON XFIRE8.0 HD, USB Audio #1
Direct hardware device without any conversions
hw:CARD=HD,DEV=2
AUREON XFIRE8.0 HD, USB Audio #2
Direct hardware device without any conversions
plughw:CARD=HD,DEV=0
AUREON XFIRE8.0 HD, USB Audio
Hardware device with all software conversions
plughw:CARD=HD,DEV=1
AUREON XFIRE8.0 HD, USB Audio #1
Hardware device with all software conversions
plughw:CARD=HD,DEV=2
AUREON XFIRE8.0 HD, USB Audio #2
Hardware device with all software conversions

cheers,
Andy

6

can you try any of the hw names?
Other than that, this might just be ALSA strangeness; as far as I have
had a glimpse at the code, about 2 years back, the audio blocks don’t do
anything “special”.