Parametric EQ in Procedural EQ Rule Doesn't Play Mono Mp3s (Roon Investigating)

Hi @Alan_McMillan,

That’s incredibly unfortunate and I’m very sorry to hear about the speaker. I will push on my end to pin down and resolve the mono playback issue using the diagnostics tech support has already collected, so when your system is returned you can enjoy it without issues in Roon.

Thanks @connor. I’ll contact you again when my system’s back up and running.

Hey @Alan_McMillan,

Just a quick thought - what are the channel assignments on your Parametric EQ in the screenshot you’d shared?

I’m also curious if you have “Downmix as needed” or “Channel mapping only” in your Device Setup for the 218.

Logs suggest that the Procedural EQ rule you’ve set might be triggering a channel mapping scenario in which Roon sends a non-existent L or R channel to your output.

You mentioned there aren’t other DSP filters involved with this device. Is there a particular reason you’re applying the Parametric EQ embedded in a Procedural EQ rule? It seems conditions are stationary if you’re not playing back to a 5.1 or 7.1 setup.

Once we’ve reviewed the settings about which I’d inquired above, I recommend creating the same notch filters in the standalone Parametric EQ function, as it will remove an additional layer of channel mapping that might be interfering here.

Thank you again for your boundless patience. I know this hasn’t been a great showing on our part, but we’ll be diligent and prompt in our responses.

Hi @Connor
The channel assignments on the original screenshot were 1 & 2. The 218 was set to downmix as needed although it never occurred to me that this might apply to 5.1 or 7.1 setups. I come from an era when downmix meant stereo down to mono!
I also didn’t understand that the parametric EQ could be standalone. I opened the procedural EQ, saw the parametric stuff and took it from there.
I have now recreated the filters in a standalone instance of the parametric EQ.

There doesn’t appear to be a channel assignment at the bottom though. Am I missing something?
Should I also switch the 218’s downmix as needed to channel mapping only? Unfortunately, as I said earlier, I can’t test any of this yet. :unamused:

Thanks for coming up with all this. I’m embarrassed to think it might have been finger trouble all along!

Hi @Alan_McMillan,

Thank you once again for the detail of your report. In a significant development, the team have actually been able to reproduce this issue when we use the Procedural EQ with an embedded Parametric EQ as a rule (ie. the original conditions from your report) and play back Mono mp3 content like the file you sent. It’s an issue within Roon’s Procedural EQ, as far as we can tell.

In at least one case, reproducing had far more serious consequences for playback and required creating a new RAATServer instance. I would recommend taking this RAATServer refresh step in your case as well, just as a precaution.

You can generate a new RAATServer instance on your device by following these instructions, but please be aware that this will reset your Roon Settings → Audio Tab to factory settings and I would advise making a backup of any custom DSP settings you have (other than, of course, the Procedural EQ rule that doesn’t work :wink: ):

  • Create a Backup of your current Roon database
  • Exit out of Roon
  • Navigate to your Roon’s Database Location
  • Find the folder that says “RAATServer”
  • Rename the “RAATServer” folder to “RAATServer_old”
  • Restart the Roon App to generate a new RAATServer folder

The team will investigate the issue with multiple filters in Parametric EQ in Procedural EQ rules earnestly with a dedicated ticket. Thank you for bringing it to our attention.

Fair question. Now that we’ve identified the issue on our end with the Procedure EQ → embedded Parametric EQ, please disregard my earlier instructions regarding mixing, channel mapping etc.

In the meantime, I recommend keeping the “Downmix as needed” setting applied in the Device Setup and recreating these notch filters in the standalone Parametric EQ filter. You shouldn’t have any issues playing back Mono files if the rule isn’t embedded in the Procedural EQ.

I hope all is progressing well with the speaker repair in the meantime. We’ll be watching once you’ve had a chance to test.

Hi @Alan_McMillan,

I’ve reopened this thread and we have an open ticket related to the issue you’re experiencing on the schedule for senior development to address in the near future. We’ll post as soon as we have a further update. Thank you for your continued patience.

Hi @connor
I just got my Meridians back form recapping and I tried the fix you suggested. It works. The mono files play normally now that the parametric EQ isn’t embedded in the Procedural EQ. Thanks for your help.

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