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DAC+ADC Pro issue with Alsaloop

Hznberg

February 03, 2020 10:24

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Hi,

Playback works as usual fine with hifiberry products, but analog in via Alsaloop gives underrun for playback hw:0,0. No sound.

As I compare the "standard" Dac+ADC with the Pro version, are physical jumpers still necessar?. Mine came without.

I bought the card for the ADC functionality primarily...any idea how to solve?

Regards,

Ronnie

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7 comments

• 1
  
  HiFiBerry team February 03, 2020 11:17

  alsaloop is a beast. It needs to right set of parameters to run stable.
  On HiFiBerryOS, we're using these:
  
  /bin/alsaloop -P default -r 48000 -f S32_LE -t 100000 -S 1
  
  Also make sure, no other process is using either input or output already.

  There are no jumpers on the DAC+ ADC that need to be set. Have a look at the data sheet here:
  https://www.hifiberry.com/docs/data-sheets/datasheet-dac-adc-pro/

  Best regards,
  Daniel

   

  Edited by HiFiBerry team February 03, 2020 11:18
• 1
  
  Hznberg February 13, 2020 18:20

  Hi Daniel, 

  Works now almost glitchfree with : alsaloop -C hw:1,0 -P default -r 48000 -f S32_LE -t 100000. 

  Sensitive beast.

  Thanks and regards,

  Ronnie

   

• 1
  
  pander February 17, 2020 01:45

  For my Raspberry Pi 2 Model B with Raspbian Buster, this works:

  arecord -d5 -c2 -fS16_LE -r48000 -Ddefault:CARD=sndrpihifiberry /tmp/tst.wav
  arecord -d5 -c2 -fS16_LE -r48000 -Ddefault /tmp/tst.wav
  arecord -d5 -c2 -fS16_LE -r48000 /tmp/tst.wav
  
  aplay -Ddefault /tmp/tst.wav
  aplay -Vstereo /tmp/tst.wav
  
  alsaloop -c2 -fS32_LE -S1 -t100000 -Cdefault:CARD=sndrpihifiberry
  alsaloop -c2 -fS32_LE -S1 -t100000 -Pdefault
  alsaloop -c2 -fS32_LE -S1 -t100000

  Don't forget to comment out the line dtparam=audio=on in /boot/config.txt and use the audio output of the DAC+ADC Pro.
  
  

  Edited by pander February 17, 2020 04:56
• 1
  
  pander March 09, 2020 23:19

  Question for HiFiBerry team and others, why can alsaloop work with 32 bits and arecord only with 16 bits?

  PS for less overruns with arecord, I added --buffer-size=192000 any pointers on that too?

• 1
  
  HiFiBerry team March 10, 2020 05:51

  arecord can also use 32bit. However, arecord isn't really a good tool to record at all as it doesn't create WAV headers with the correct metadata. I would recommend to use sox instead.

  In general: the axxxx tools aren't really optimized for the ALSA on SOC sound subsystem. They work, but require a lot of tweaking as you noticed.

• 1
  
  pander March 11, 2020 23:21

  Do you have some example commands that work with the DAC+ ADC Pro? I have tried many combinations, but none result in useful WAV file. Minimal example that should work (but doesn't) is:

  rec -V3 -p trim 0 5 | sox -p out.wav

  Tried combinations with sample rate of 44100 and output in 16 bit (this example results in 32 bits). Either the signal is 0 and cannot be amplified or the signal is (when amplified) only noise.

• 0
  
  pander March 18, 2020 14:31

  Does anybody have some working example please?