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DAC2 HD + DSP High Pitched Noise on Pause

Nathan Upchurch

July 21, 2022 14:58

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For some time now, I have had an issue with a high-pitched noise / squeal / ringing occurring on pause with the DAC2 HD + DSP, while streaming via DLNA:

• If paused during playback, the noise occurs
• When moving between tracks, the noise sometimes occurs
• If there is nothing playing and no tracks queued in the DLNA playlist, the noise does not occur

I have had this issue since I got the device, which was a number of software updates ago, but kept forgetting to report the issue until now even though it makes relaxing to an album at night pretty difficult!

Here is a recording featuring a track playing, the track being paused, and the resulting noise: https://transfer.upchur.ch/jN9Mhk/HifiBerryNoise.m4a 

My Setup:

• Pi model: Raspberry Pi 4 Model B Rev 1.4
• Sound card: DAC2 HD + DSP Module
• Mixer: DSPVolume
• HiFiBerryOS version: 20220228
• Linux Version: Linux hifiberry 5.15.24-v7I
• DSP Program: DAP add-on version 13
• Amp: Sony STRDH190

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10 comments

• 0
  
  HiFiBerry team July 22, 2022 04:43

  I guess that doesn't happen without the DSP add-on?

• 0
  
  Nathan Upchurch July 22, 2022 05:43

  Hi there, thanks for your reply. I haven't tried removing the DSP because the unit is hard to get to. Is there a way that I can disable via SSH or the web interface for testing purposes?

• 0
  
  HiFiBerry team July 22, 2022 05:53

  No, routing through the DSP can't be changed in software.

• 0
  
  Nathan Upchurch July 22, 2022 05:56

  Ok, I'll test it without the DSP and let you know whether the issue is present.

• 0
  
  Edward Archibald November 11, 2022 19:41

  Hello Nathan, were you able to test without the DSP?  If so, what where the results?  If not, I can test it that way since I can easily get to the DSP board.  I hit a similar/the same issue and it's completely reproducible in my environment.  I have Apple TV 4K set up to stream the audio over Airplay to a DAC2 Pro with DSP add-on.  I have HifiBerry-OS 20220826 installed on a Raspberry Pi 4 Model B Rev 1.5 and have the DSP Add-on 13 installed.  I am using saved listening modes - one derived from a generated room compensation - that works great! - and one that I use for headphone compensation.  It doesn't matter which compensation profile I use to get this problem.  What I do to recreate the problem is, first, to reduce the speaker volume to just audible.  Then I press the pause button on the Apple TV 4K remote control and leave it paused for about 10 seconds. When I resume from the pause, I get a very high pitched sound for a duration of 2-3 seconds.  From time to time, instead of the high pitch, I get a low rumbling.  I can also reproduce this issue when playing music via Tidal over Airplay.  Pretty much the same scenario: pause the music - in this case for about 15 seconds - and when I resume the music playing I get the high pitched sound about 7 times out of 10.  I also notice, with the music, that the notes that I would expect to be playing after I resume the music seem to have been 'swallowed up' Sounds like some sort of a audio/samples buffering-related issue. I also notice that the length of the high pitched tone is about the same length of time that it usually takes for playback to resume i.e. the noise begins almost immediately followed by the music.  If some other folks in this community can try this scenario, or something similar, I would like to know of you see this issue as well.

• 0
  
  Edward Archibald November 11, 2022 19:50

  P.S. In thinking about the 'does it happen without the DSP add-on' comment, I decided to try a test case where I am using a 'saved preset' that does not have any filters added to it.  When I play back music using this preset, the problem does not occur at all and it occurs nearly every time I use one of my saved presets both of which have 10 or more filters - one using AutoEQ derived parameters and one using a generated room compensation set of filters. Hope this helps. I'm happy to try other experiments in order to get to the bottom of this.

• 0
  
  Edward Archibald November 11, 2022 20:41

  The following link contains a .json file that can be used to reproduce the problem.  It is a saved 'listening mode' and contains 8 filters. 

  https://drive.google.com/file/d/13xpANMntcrPPLrRQywEnGHRCXzicablh/view?usp=share_link 

  To reproduce the problem:

  - download the file and copy it to HifiBerry into the /etc/beocreate/beo-listening-modes directory

  - systemctl restart beocreate2.service

  - Make sure that the volume is turned down to a just audible volume on your headphones or speakers. Thankfully I didn't have the headphones on when I first encountered the problem but they were turned up to a high volume and it appears that perhaps the headphone amp is fried... More on that later.

  - Navigate to Sound->Parametric Equaliser->Sound Design

  - Click on the 'View saved presets' link towards the bottom of the page.

  - Click on the ReproducesSquealingProblem link to enable the listening mode

  - Play music via Airplpay.

  - Pause the music playback for a good 5-10 seconds.

  - Resume music playback. 

  I observed that I saw this problem reliably 7 out of 10 times. I would like to know if others could get the same result.

  I also uploaded another 'listening mode' file - this one does not contain any filters. I just wanted to see if I still got the issue with the DSP board simply present but not being set up with filters. I cannot reproduce the issue with this file.  The name of the listening mode is 'Flat'.  Just use the same process as outlined above vis-a-vis copying the file etc. and you should not be able to reproduce the problem.

  https://drive.google.com/file/d/1phEuQs7C5xnC3DSAk5d2dY_yCZRb_WC3/view?usp=share_link 

  Edited by Edward Archibald November 11, 2022 20:44
• 0
  
  Neuman Ben January 04, 2024 00:16

  I also have the same problem. Would be great to hear from HifFiBerry team.

• 0
  
  HiFiBerry team January 04, 2024 07:49

  If you have a specific issue with filters in the DSP settings, please create a bug report for HiFiBerryOS. 
  https://github.com/hifiberry/hifiberry-os/issues
  
  Make sure, you test the latest HiFiBerryOS64 as this includes the latest DSP profiles.

• 0
  
  Neuman Ben January 04, 2024 17:38

  Submitted new issue: https://github.com/hifiberry/hifiberry-os/issues/498

  Will test with new OS64 when I get a chance.