A question about DSP

I’ve set up a couple of notch filters to take out acoustic humps in my listening room at 50Hz and 63Hz. They work very well indeed. My problem is when I try to listen to mono MP3 files. If the filters are enabled, the MP3 files will not play. Once the filters are disabled, the MP3 files then behave as normal.
What’s the issue here?

Ive moved this to the #support area. you will likely be asked to provide more system details as noted below

Include information about your hardware and operating system under Core Machine. Under Networking Details let us know how you connect to the internet at home, so we can better understand how your devices are connected and the way your network is set up. Audio Devices is meant to cover your devices and their connection type (USB, HDMI, etc.).

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Hi @wizardofoz
My system’s details are as follows:

Core machine: QNAP TS251 running the latest firmware.
Networking: Ethernet through unmanaged switch.
Audio Devices: Meridian 218 Zone Controller connected via ethernet sending to a pair of Meridian 7200.2 Digital Active Loudspeakers.
Remotes on Windows 11 and iPad

did you install ffmpeg on the qnap? not sure if this is the issue but it might be needed to re-encode the files back from PCM in the DSP process…I could have that all wrong tho.

It’s not installed so I’ll give it a try.

I installed ffmpeg but it made no difference, so I removed it again.

Hi @Alan_McMillan,

Thank you for the report and I’m sorry you’ve been having difficulty playing back certain files.

I have a few quick clarifying questions to help expedite the tech support team’s investigation:

  • Are these mono MP3 files failing to initiate playback at all (as in, Now Playing indicator and scrollbar remain at 0:00), or are they playing back, but inaudibly? We’ll want to clarify whether it’s a filter/mixing rule issue or an issue with the files themselves.
  • Are you able to upload a screenshot of the settings for the two notch filters you’ve created?
  • Do you have any other filters, EQ, mixing rules, or additional DSP applied in Roon? Please also share screenshots of these, if so.
  • If possible, please upload an example of an affected mono MP3 file using this uploader.

We’ll keep an eye out for your response.

Hi @connor
To answer your questions:;

The files play, but inaudibly. Below are the settings for the two filters…there are no other DSP parameters set up on the system. I have uploaded one of the affected files but I can tell you that every mono MP3 file I have is affected by this issue.

These settings are applied to channels 1 & 2 only.

Hi @connor
Is there nothing that has been found out about this yet?

Why is no one responding to this issue?

Hi @Alan_McMillan,

Please accept our apologies for the unacceptable duration of silence. To update you on the status of our investigation, our initial efforts to reproduce the issue have been unfruitful, so we’ve escalated the issue internally.

The QA team should have an answer shorlty. I’ve passed along the example of an affected file and the particulars of your device settings. Thanks for your patience.

Thanks @connor