Raspberry Pi and Karaoke Machine (Wolfson Pi Use and its Limitation)

Hi!

I don’t know why wolfson pi don’t record 8000Hz or 16000Hz sample rate audio format

Those limitations crept in by mistake. This post explains:Re: PJSIP/PJSUA with Wolfson audio card

1. Unable to record 8000Hz/16000Hz sample rate format audio.
2. Unable to record 8-Bit audio format.
3. Unable to run 2 or more sound application using wolfson pi at the same time. (So definitely when I use it in karaoke either I hear music or I can loop back my voice).
   Getting error resource or device busy when using 2 sound instances at same time.

You could try my .asoundrc.

Save this script as /home/pi/.asoundrc (make a copy of the original first, just to be safe).

#######################################################################
#
# Use libsamplerate instead of internal resampler.
# You might have to: sudo apt-get install libasound2-plugins
# Or just comment out the next line if the internal one is good enough for your needs.
defaults.pcm.rate_converter "samplerate"

######################################################################
#
# Wolfson Audio Card for Raspberry Pi
#
pcm.wolfson_pi_soundcard {
  type hw
  card sndrpiwsp
  device 0
}
# Create a Master volume control
pcm.softvol {
  type softvol
  slave {
  pcm "pduplex"
  }
  control {
  name "Master"
  card 0
  }
}

pcm.!default {
  type asym
  playback.pcm "plug:softvol"
  capture.pcm "pduplex"
}

#####################################################################
#
# Mixing and resampling goodness :-)
#
# Several clients can record and play back simultaneously.
# The dmix and dsnoop plugins operate at 48kHz by default, i.e. the sound card will be kept at 48kHz at all times.
# All playback streams are converted to 2 channels/48kHz/16bit.
# All recording streams are converted from the card's 2 channels/48kHz/16bit
# to the requested number of channels, sample rate and bit depth.

# We define one pcm device called "playmixer" for playback.
pcm.playmixer {
  ipc_key 140324 # Any number will do, as long as it's unique in the system.
  ipc_key_add_uid true
  type dmix
  slave.pcm "wolfson_pi_soundcard"
}

# Define another one called "recmixer" for capture.
# The sound card will run at 48kHz and input is resampled to the requested rate.
pcm.recmixer {
  ipc_key 140325
  ipc_key_add_uid true
  type dsnoop
  slave.pcm "wolfson_pi_soundcard"
}

# Define a duplex device, with both in- and outputs.
pcm.duplex {
  type asym
  playback.pcm "playmixer"
  capture.pcm "recmixer"
}

# Add a "plug" plugin for the above "duplex" device.
# This is where all the converting takes place.
# Sample rate, number of channels, bit depth.
# By the way, who thought that "plug" was a good name for a plugin?
#
# Use this device for all your playback and recording resampling needs.
pcm.pduplex {
  type plug
  slave.pcm "duplex"
}

# A ctl device to keep xmms happy
ctl.pduplex {
  type hw
  card 0
}

# A DSP to keep the alsa-oss layer happy:
pcm.dsp0 {
  type plug
  slave.pcm "duplex"
}

ctl.mixer0 {
  type hw
  card 0
}

You should now be able to record at 8000 and 16000 and in 8 bit in both mono and stereo, using the "default" device.

--

Ragnar

Hi,

I am getting error

ALSA lib conf.c:1686:(snd_config_load1) _toplevel_:18:1:Unexpected char
ALSA lib conf.c:3406:(config_file_open) /home/pi/.asoundrc may be old or corrupted: consider to remove or fix it

Also I have installed the libasound2-plugins.

Any other suggestion.

~ Sumit Rai

It seems that if you copy the text from the "view plain" box, extra characters are inserted when you paste it into your editor.

I just tested that and I get the exact same errors as you do.

Try with the "expand source" and copy the text from there.

--

Ragnar

Hi Ragnar,

You rocked again 

Thanks alot, everything is now working.

~Sumit Rai

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