My Meridian 818/DSP8000SE combination can decode MQA.
I think I understand how Roon supports MQA.
But some possibly related questions.
If I want to use Roon DSP room connection with MQA, I must use Roon to do first decode, correct? DSP will still prevent device MQA unfold and decode, right? The release notes say, “Roon will not only be able to perform DSP on unfolded MQA content, it will do so without destroying the MQA Signalling information–meaning: it is now possible to use features like EQ, Room Correction, and Volume Leveling while still taking advantage of the rendering capabilities of your MQA DAC.” (My emphasis.) So even though the hardware is capable of MQA unfolding, I should turn on Roon unfolding.
However, when I do that, the Meridian does not recognize the MQA data so it doesn’t do the further decoding. At least that’s what I see. Anybody can confirm?
I see that with the network connection (ID42). Haven’t tried MicroRendu/USB input yet…?
So with this gear, I have a choice for MQA: allow room correction, or get full MQA unfold. (Easy choice, nothing will make me give up DSP, and the DSP8000SE upsample to 768k anyway.) Right?
The Meridian default setting says Not MQA enabled. Is this because the Roon team made a choice of DSP in this case?
Correct. Processing the original MQA file directly would destroy its MQA-ness. The unfold is data decompression–the lower bits of the file contain a bitstream. Once it’s unfolded, it looks like 88.2kHz or 96kHz PCM with a tiny bit of metadata buried in it. It’s that unfolded stream that is suitable for processing.
This is a limitation on Meridian’s side. MQA is aware. Meridian is aware. I’m not aware of the ETA for resolving it, but my understanding is that they plan to.
Someone who tracks Meridian hardware a little bit more closely would know the precise scope of products that have this limitation, but I believe that all of the stuff that uses “MHR” terminology is affected.
For the time being, yes.
There’s no way for us to determine MQA support level from the Meridian network protocol, and a lot of inconsistency in what is/isn’t supported by various configurations, so we didn’t want to assume. I conveyed our willingness to read this support information off of the protocol were they to provide it. Hopefully they will fill that detail in, too. If not, manual setup will be required.
That said–regardless of the setting that you choose, DSP capabilities are preserved. If Roon thinks that the DAC can perform MQA rendering at the end of the chain, it will also do extra steps to preserve the rendering information. If not, then everything still happens more or less the same way, we just don’t do the extra work.
Imagine I don’t use DSP and tell you the hardware does MQA, you will not do MQA unfolding but leave it to the hardware. Correct?
And then if I switch on DSP, do you automatically take over MQA processing?
Or is this all controlled by the core MQA setting?
That setting is basically just a big “off” switch for people who don’t like MQA. That’s why it’s buried in advanced. When it’s “on” Roon is making the best choices automatically based on:
The details of the media file
The hardware’s MQA support capabilities
The DSP configuration
The settings roughly do this:
If we think the device can unfold, we’ll let it perform the whole MQA process on the original source file unless there’s a reason not to (DSP)
If we think the device can render, we’ll take steps to preserve/restore rendering information, and automatically disable upsampling in Roon (which would prevent rendering in the DAC)
If we think the device has no MQA support, we’ll unfold the file, assuming that the device supports the unfolded format (24/96 or 24/88 depending on the file).
That said, you don’t have to tell the truth in the settings window…so all of the flexibility is there to get things done however you like. It is just there without making everyone think about a bunch of tweaky low-level choices.
8Thanks for a great update Brian,
I just disabled the dsp button on the top left of the screen shown below as I didn’t think I used DSP. Now I’m wondering if 1.5 has this on by default to unfold MQA. Should I enable this again? Also you mention a MQA on/off switch in advanced settings. Where are the advanced settings? I can’t locate them and just want to check roon MQA dcoding /unfolding is on. At present I am very happy to let roon make all the audio decisions for me.
That’s exactly what it should do.
Which is what I should assume, without asking
One more case: if the device does no MQA at all, but supports high bit rates, I can set up Roon to do MQA unfolding and generic sample rate conversion, which is not MQA rendering because the MQA license does not allow that, correct? And without inside information, it appears to me the difference between generic upsampling and MQA rendering is not as big as originally claimed.
Correct up to “because the MQA license does not allow that”.
The reasons why you can’t upsample then render are technical, not licensing related. The rendering instructions are specific to the 88.2kHz or 96kHz unfolded stream, and wouldn’t retain the same meaning if applied to a higher rate stream.
Yes, I understand that.
I meant that after unfolding, a hardware device can do rendering which is upsampling under MQA controlled parameters, but Roon doesn’t do that, right? I thought that was a licensing constraint. Or am I wrong? Do you do both unfolding and rendering?
Sorry, misunderstood. You’re right–Roon cannot render. I was explaining something slightly different.
Rendering is always happening within the DAC. Often it involves sample rates that can’t be processed by the DAC’s interfaces…so a definition of rendering that allows for out-of-DAC processing might not be quite the same way that MQA defines it today.
I have the same problem with my Meridian 218/7200SE combination. The Roon “signal flowchart” tells me that MQA files are recognized, then treated with my room correction filters and finally presented again as MQA files to my Meridian 218, but the 218 doesn’t seem to recognize the file as MQA. The light does not come up and the speaker says": “MHR” instead of “MQA”. So I guess we’ll be waiting for a Meridian firmware update.
Apart from this little glitch - which I trust will be resolved - I think Roon 1.5 is just absolutely fantastic.
I would like to understand why there is a difference in the output display stage after MQA 1st unfold when my Dragonfly Red is connected to iMac vs when it is connected to USBridge? Are the audio outputs eventually the same from the DFR in both cases? I noticed that on iMac, I can see the Exclusive Mode set, but in the USBridge setting, there is no Exclusive Mode displayed.