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DAC2 HD with DSP

Mans Frisk

October 29, 2020 11:44

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Hi

I have just installed the DSP on the DAC2 HD i got some months back. Using the available problems i encountered some problems which I want to understand before starting to make my customized profiles. For

• DAC+ DSP Universal 48 kHz - NO sound except high frequency tone

• DAC+ DSP Universal (96kHz) and DSP add-on - high frequency distortion especially when source is 24 bit PCM but also audible using Spotify Connect

I have not heard the (digital?) distortion before, when using the DAC2 HD alone neither do I have it playing music from the same sources and on the same equipment using a HifiBerry DAC+ Pro. In both cases I am running the HifiBerry on RPi 3b. 

Any proposals what to test?

Regards

 

 

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26 comments

• 0
  
  HiFiBerry team October 29, 2020 13:27

  You need to use the DSP profile for the DSP add-on. The DAC+ DSP profile is not designed to work with the DSP add-on. 
  However, I can't say anything about the distortion at the moment. For the DSP it doesn't really matter if the source is 16 or 24bit as everything will be handled the same way internally. 
  I can try to do some measurements in the next week to check if there is a problem with the DSP profile.

• 0
  
  Mans Frisk October 29, 2020 14:32

  After testing i ended up using the profile "DSP add-on", greatful if you can do measurments.

  Thx in advance.

• 0
  
  HiFiBerry team November 02, 2020 12:46

  I think, I found a bug in the DSP profile. Can you try the following command and test if this fixes the problem for you.
  

  dsptoolkit write-reg 0xf146 1

• 0
  
  Paul Rosen November 03, 2020 04:48

  I had a similar issue with high frequency distortion with the DAC HD 2 + DSP combination.  The recommended dsptoolkit command fixes it for me.  Thank you!

   

• 0
  
  HiFiBerry team November 03, 2020 05:53

  Thanks for the feedback. We'll fix this in the next version of HiFiBerryOS.

• 0
  
  Mans Frisk November 03, 2020 07:02

  Works for me also after some struggling (with DSP Toolkit) late yesterday evening.

  Do I understand it correctly that this is not a profile problem with DSP add-on but a OS problem? 

• 0
  
  HiFiBerry team November 03, 2020 07:03

  No, it's basically a problem with the profile that has one setting wrong.

• 0
  
  HiFiBerry team November 05, 2020 13:52

  Ok, the updated profile is ready for testing:
  https://raw.githubusercontent.com/hifiberry/hifiberry-os/development/buildroot/package/dspprofiles/dsp-addon-96-12.xml
  
  If you want to test, you can download this and copy it to /opt/beocreate/beo-dsp-profiles
  
  We'll include this in the next HiFiBerryOS release

• 0
  
  Mans Frisk November 05, 2020 19:25

  Tested with good result!

• 0
  
  Paul Rosen November 05, 2020 19:58

  I assume you mean copy to /opt/beocreate/beo-dsp-programs, correct?

   

• 0
  
  HiFiBerry team November 05, 2020 20:44

  Yes

• 0
  
  Paul Rosen November 06, 2020 03:30

  It doesn't seem to work for me.  I copied in the file, rebooted, and the distortion returned.  It is possible it is less distorted, but hard to tell.  I then write the register as you previously suggested and it clears up again.  Not sure why it would work for Mans and not me.

   

• 0
  
  HiFiBerry team November 06, 2020 05:24

  You also need to install it onto the DSP, not only copy it.

• 0
  
  Mans Frisk November 06, 2020 07:30

  Beeing in directory /opt/beocreate/beo-dsp-programs I used "curl -LJO https://raw.githubusercontent.com/hifiberry/hifiberry-os/development/buildroot/package/dspprofiles/dsp-addon-96-12.xml"

  - wget did not work, I am using Hifiberry OS.

  This was the first time for me to use curl and it worked. The profile was copied and got installed, I have to admit that I was surprised that the profile was installed, I did not expect this. Maybe HiFiBerry team can explain?

  

• 0
  
  HiFiBerry team November 06, 2020 07:33

  As you have selected "Upgrade automatically", the profile has been upgraded to the latest version after a reboot.

• 0
  
  Paul Rosen November 06, 2020 17:54

  Full disclosure - I am relatively new to this world, so I no doubt will do dumb things.  I thought a reboot would automatically search the these directories and install the profile.  Thanks for that clarification.

  But now I'm searching through the online documentation to figure out how to install the profile.  I find reference to install-dsp-profile software in beocreate tools.  It is not installed on my device.  The instructions for installing it involve apt-get and git, neither of which are on the machine, and other places say apt-get is not supported since it is non debian.  I can keep pouring over the documentation, but if you could point me to a single definitive source that would help me with the step-by-step it would be much appreciated!

   

• 0
  
  HiFiBerry team November 06, 2020 18:01

  Are you using HiFiBerryOS? You can simply install it from the GUI (Sound/DSP programs)

• 0
  
  Paul Rosen November 06, 2020 18:13

  Oh my. Of course!  I had kind of forgotten about the gui since I've been tackling a number or problems on a variety of fronts.  I found it and have installed it.  I guess it will work now.  Thanks for your patience. Very helpful!  Much appreciated.

   

• 0
  
  HiFiBerry team November 06, 2020 18:13

  You're welcome

• 0
  
  Paul Rosen December 14, 2020 05:36

  Hi there.  Is it possible that the output channels on the DAC2 HD are swapped left/right?  I’m asking because I was comparing my DAC ADC board to the DAC2 HD (two separate pi’s plugged into two channels of a preamp.  In playing a test recording the DAC ADC has left/right correct and the DAC2 HD has them reversed.  I am pretty sure that the cables are correctly plugged into jacks.  Colors match and are consistent.  Is there a way to switch the channels?

   

• 0
  
  Mans Frisk December 14, 2020 06:21

  I have noticed the same and swapped the channerls in  the settings, in other words default settings is mixed.

• 0
  
  HiFiBerry team December 14, 2020 07:24

  Yes, they are swapped. You can either change this in the channel settings or just wait for the DSP profile v13 that comes with the next HiFiBerryOS release.

  If you want to try, you can test the experimental release with this profile using
  
  /opt/hifiberry/bin/update --experimental

• 0
  
  Paul Rosen December 14, 2020 21:05

  Thank you!

• 0
  
  Douglas Gardner February 24, 2021 21:23

  HiFiBerry team Wanted to point you over to a review with measurements that was published on Archimago's Musings blog at this link. Overall I think it's a nice review that may inspire folks to give it a try. There are a couple of measurements that were done that I wanted to draw your attention to.

  1) Looks like the DSP add-on board may be inverting phase in the default configuration. I imagine that's easy to fix in the OS or the DSP Add On software. Not audible but present none the less. Also not sure if this only happens with the DAC 2 HD or with other boards like the Amp100. 

  2) There seems to be a bit of high frequency noise outside of the audio band when using the DSP board. I was wondering if that's something that should or could be suppressed in the filter design for the DSP module in future OS releases.

  Congrats on getting some additional coverage of these devices. 

• 0
  
  HiFiBerry team February 25, 2021 07:31

  1) Looks like the DSP add-on board may be inverting phase in the default configuration.
  While we think, the concept of "absolute phase" isn't meaningful for a playback device, you can invert this in the UI
  
  2) There seems to be a bit of high frequency noise outside of the audio band when using the DSP board. 
  While we could just implement a steep filter, we don't think that's a good idea as it also will have impact on phase response. 

• 0
  
  Gregvds0 March 30, 2021 16:05

  How are week-end able to invert phase in the GUI? Where?

  Thanks :-)