“MQA Signaling” and “ALSA”

I have three components: modem, NUC/ROCK, and LS50W I. I have used two different, yet equally successful, ethernet wiring configurations:

  1. The conventional way… LS50W and NUC each individually hardwired to the modem.
  2. The NUC chained BETWEEN the modem and LS50W, with NO direct connection between modem and LS50W.

WiFi is disabled in both setups, and both sound great, albeit, slightly different.


Under configuration 2, two terms appear in the signal chain that do not appear under configuration 1: “MQA Signaling” and “ALSA.” What does this mean? What is happening in 2 that is not happening in 1?

I’m eager to understand this. Thanks!

Feel free to post screenshots of Roon’s entire signal path that show the different entries you have questions about.

You should also visit the Roon help center and read some documentation about Roon - so you can avoid asking questions already answered there.

And for other potential helpers, please read the related previous thread.

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MQA signaling enables the complete end-to-end process even when you apply DSP between the initial decoding and final “unfold”. For those of us who value MQA sound quality, this is the desired signal path.

Your modem has a switch in it so your basically just connecting both to the same ethernet switch. Yes, conventional.

Need more details here. Using USB out of the NUC or your NUC has 2 ethernet ports?

Need screenshot of both signal paths. In one configuration something is returning extra info to Core but its unclear from your description what that thing is. Need the screen shots and more details about the exact cabling being used for config 2.

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Thanks. However, I know what both ALSA and MQA are. That was not the question.

Hmmm … Let me re-read your question then …

… and it’s not that the documents I linked just explain the terms out of context, they also explain where they are used/may show up in a Roon environment and why.

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In 2 your using USB cable to connect to the Kef’s. This makes the steamer the NuC and not the speakers, the Kef’s are seen purely as as a DAC in this setup. ALSA is how Linux operating systems deal with audio and connected devices. ROCK is a flavour of Linux and thus uses ALSA to output audio to devices digitally in your case to the Kef’s via USB. As the ROCK is handling the stream it’s also likely setup differently to the Kef in regards to MQA processing in the device settings. Without seeing an image of the signal from Roons now playing screen playing same source its hard to say what the difference are. Mqa signalling usually comes in when some DSP is involved in the chain as if Roon is set to be the MQA core decoder it can apply DSP and maintain MQA signalling so a MQA capable DAC will still see it as MQA and render it to the next MQA stage. This is why your signal path is important to determine why or what Roon is doing differently in each setup.

With the speakers as the endpoint your only concern is ‘how’. Ethernet is self explanatory. You are engaging the speakers as an endpoint via IP. When you see ALSA you are talking to a USB connected device. The MQA messages don’t matter because the LS50W’s are not MQA enabled so ignore any MQA messaging they see. You can configure Roon not to forward those messages by telling it the Kefs have no MQA capability, but the default is usually to treat any endpoint as Renderer Only in the off chance it is actually MQA enabled.