Stuttering when both MQA decoding and DSP are active

I have an issue when playing music to a vero 4K in that MQA songs are stuttering or no sound at all when DSP is on.

When DSP is off, MQA plays well.

I like the DSP for upsampling some MP3 files so I turn it on regularly but then with Roon radio some MQA files come along and they stutter so I then turn off DSP.

Is it not possible that Roon detects the audio file format and change DSP on or off?

What format are you using to the 4K? Are you using RAAT or something else?

Yes the Vero is using RAAT

I notice that with my MQA capable DAC, there is a difference in Roon’s signal processing sequence (for Convolution Filter) depending on whether I have Enable MQA Core Decoder set to Yes or No. With the former I see “Preserve” MQA signaling. When it is set to No there isn’t an indication that MQA signalling is being preserved.
You might try one vs the other to see if it matters in your case. You’ll find it under Device Setup for the DAC.

Hi @grossmsj,

With Roon’s DSP active …

With Enable MQA Core Decoder set to No … Roon will not decode a MQA steam … thus if DSP is then performed the MQA stream is destroyed and what is output to the DAC is no longer MQA.


With Enable MQA Core Decoder set to Yes … Roon may decode a MQA steam …

If the DAC’s capability is set in Roon to be a MQA renderer then …

Roon will now MQA decode, preserve the MQA signalling, perform the DSP and then restore the MQA signalling.

The MQA decoded renderable signal is now sent to the DAC.

Trust this helps.

Thank you very much @Carl!
Very helpful to understand the process.

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I found that when I enabled MQA core decoder stuttering occurred if I turned on DSP… When turned, no stuttering in DSP. And the strange thing is that the stuttering seems to happen due to head room management in DSP. I have head room management on -1dB (found somewhere that this was useful…) If I disable head room management, no stuttering even when enabling MQA core decoder…but then I have also no sample rate conversion…?

Could you post a screen shot of the Roon signal path … when configured this way and this stuttering occurs.

I’m wondering what value Roon’s processing speed is.

I’ll tag @support to follow this up with you… In order for Roon’s team to better assist you, please provide a brief description of your current setup using this link as a guide.

Make sure to describe your network configuration/topology, including any networking hardware currently in use, so they can have a clear understanding of how your devices are communicating.

Roon core on VMWARE Esxi Debian on a Intel NUC7i7BNH, 16GB RAM

Connections to audio device:
All wired with Unifi switches.

Audio device:
Vero 4k connected to Marantz SR7011 optical output

I have three images:

  1. Normal FLAC file, DSP enabled, I see no processing speed.

  2. MQA file, DSP enabled, enable MQA decoder. Stutters and I see processing speeds between 20-30x

  3. MQA file, DSP enabled, disable MQA decoder. No stutters and I see processing speeds between 85-95x

Hi @Tom_den_Heijer,

Thanks for images and extra setup information … the processing speeds all look ok … so something else is going on here.

I see you are running Roon within a hypervisor, I don’t think Roon officially support that but let’s see …

As this topic has now morphed from a feature request to more support in nature… I’ve retitled and moved to #support.

Hello @Tom_den_Heijer,

Is the Vero the only zone exhibiting this behavior or are you able to reproduce on other zones as well?

Can you please reproduce the issue once more, note the exact local time + date + track that it occurs on and send me a copy of your Roon logs by using these instructions?

Hello Noris,
I do not have stuttering with an allo usbbridge if I turn on or off enable MQA decoder and turn on or off DSP.
Here are the logs:!AnF_YnMTNR-d4uhlE1iQttpE-NdZ1A?e=yclAJv
at local time 13:02 I started Empires from Elbow which is an MQA file. I had enable MQA decoder in the device setup

Hi @Tom_den_Heijer,

Thanks for the logs, let me get them over to our technical team and once we have further feedback, I or another support staff member will reach out once more.

One other idea in the meantime - I see that you mentioned you are running Roon on VMWARE in a previous post. In an attempt to minimize potential VM issues impacting this behavior, could you try temporarily hosting the Roon Core on a regular OS and let us know if the same behavior occurs? To switch Cores:

  • Open Roon on the other PC you wish to try as the Core
  • Roon Settings -> General
  • Disconnect
  • On the “Choose your Core” screen, press “Use this PC”
  • If asked to Unauthorize, you can go ahead and do so. You are limited to one active Roon Core at a time but you are free to switch between them as often as you’d like.
  • Verify if the same behavior occurs on the different PC

Hello @Tom_den_Heijer,

In the device setup options for the Vera zone, try setting the “Max Sample Rate” to 48kHz to see if you’re able to make MQA + DSP playback work.


Hello @john that was it, Thx it works now

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