Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion MQA - Related technology, products and music Two-stage MQA unfolding (software + hardware) with 818?

MQA claims to support two-stage decoding, with the first step to 88 or 96 in software, and the second stage in hardware. The Tidal desktop app does the software decode, and we believe Roon and others will too. Some hardware, like the coming update to the Audioquest Dragonfly, will do the final decode to higher rates.

I tried this, with the Tidal desktop app configured for software decoding, USB into the 818v3, and all I saw was PCM 88, no MQA indication. (To verify that my settings were correct, I switched Tidal to passthrough mode and the 818 showed MQA 352 for the 2L files.)

Has anybody seen the two-stage decoding, on an 8x8 or Explorer or Prime?
If so, is there a firmware update I need?

My 818 is connected via my network, not USB. I get MQA 352 with Tidal passthrough on or off. I'm running 4.00 in the 818.

I know there are USB drivers that have to be downloaded for the 818 but since you're seeing MQA one way and not the other that may not be the problem. I'm running legacy DSPs so obviously I'm seeing that reading on the 818 only.

Ken

How do you connect the Tidal app to the Meridian network?

Hm. I got a similar answer at the Roon forum, but it doesn't work like that, in my system.

I have tested it again. The software decoded material (both a captured file and streamed from Tidal) play only as 88, with no MQA indication on either 818 or the DSP8000SE. And the MQA content, in passthrough mode, shows MQA 352 on both 818 and speakers.

And wrt the 818 doing only the first stage, it does show MQA 352 when in headphone mode, analog output only and the speakers not involved.

I'm running Roon so I use the Tidal desktop app on my PC and Roon server on a Sonic Transporter. I use either an iPad or my desktop for control. I'm still running Sooloos as well and I'll check that this evening.

Ken

As reported back in January, in another thread on this forum, there have been issues with the TIDAL app which Meridian are aware of. I'm guessing that it's simply not been fixed.

I see the same as Anders using 808/8kSE combo.

2nd stage isn't rendered in the 8k unless the 808 does the first stage.

Will be important to see this fixed in the 8x8 given that Amarra and other well known music apps will be capable of the first stage decode into the USB input of the 8x8 units.

My dealer says M told him that what I see is intended behavior. No reason to do split decoding with an 818. And yet, MQA has published this diagram:


So this contradicts what people tell me here and in the Roon forum.
Sigh. Would be good to get some authoritative answers.

Btw, it is of course correct that with an 818 there is no reason to split the processing. But there is the room correction issue. I use Acourate to measure and calculate and Roon to run the convolution, which breaks MQA. And there is no question that REQ is more valuable than MQA. So I hope, without evidence, that Roon could implement first stage decode and DSP while allowing 818 final decode.

If Roon at some point does decode the first stage and then applies REQ that stage of decoding would make it through if I understand things correctly. What would you expect to see on the 818 and SEs?

Ken

The diagram implies that second stage MQA can work after the DSP, although personally I don't understand how, the data tucked away down in the noise is radically changed by the EQ. And some people on the Roon site tested with DSP and a Mytek and it did not work.

But in any case, my 818 doesn't do the second stage processing, even in the absence of DSP. Unclear today whether it should. I had expected that it would.

In your system now is Roon applying convolution before or after Tidal or your 818 does the first stage decoding?

Ken

Today's configuration: the Tidal app is not involved. Roon plays Tidal by pulling from the cloud (or my own files), applies DSP REQ, and sends it to the 818. Roon does not do software MQA processing (yet). With Roon DSP active, the 818 cannot decode MQA; without DSP, it does.