Overall I just think MQA sounds better. The amount of content is still too small but what is available sounds pristine and beautiful and the fact ROON gives me a ‘blue’ light and zero to 2 white lights on my ME2 is an added plus. I DO think A+3 sounds even better than ROON MQA or TIDAL’s desktop app-sorry just my opinion per my 70 yo ears but anything by ROON TIDAL HiF/MASTERS or Qobuz FLAC is far better than what i listened to 10 or 50+years ago-it’s music Nirvana I like it all.To me and I bet most of us what matters is the SQ and who really cares how it got so good it ALL just sounds better-some of us still work 60hrs a week and have no time to masticate the minusha(sic) of all the other ‘stuff’.
bobbmd
2 Likes
I have posted links below to two Tidal MQA 30 second excerpts. The first is 24 bit 44.1 kHz with MQA set to passthrough. The second is 24 bit 88.2 kHz with MQA set to software decoding.
https://dl.dropboxusercontent.com/u/81376223/2Lpassthrough.flac
https://dl.dropboxusercontent.com/u/81376223/2Lsoftdecode.flac
I would appreciate any volunteers with MQA hardware decoding to download and play both clips, then report your findings. Neither clip is tagged as MQA, but hardware decoding should identify both as MQA. Assuming all works as expected, the second clip could be useful in testing a software decoding -> intermediate DSP -> hardware decoding signal path.
AJ
What do you mean that the content is set to passthrough or software?
That’s a runtime setting, how do you set that in the content?
Caution: I put these two tracks in one folder, but Roon recognized only one.
I put them in two different folders, and it turns out both have track number 2, so Roon had trouble when both were viewed as the same album.
The Tidal desktop app can be set to MQA passthrough or MQA software decoding. The two files are of the same 30 second excerpt, one set to passthrough, the other with software decoding enabled.
AJ
The 2Lpassthrough file is played as 24/44 by Roon, my Meridian box shows it as MQA 352.
The 2Lsoftdecode shows up in Roon and the Meridian as 24/88. You mean you did a soft decode and captured the output?
In that case I understand the test. Ignore my previous question.
The Meridian 818v3 didn’t indicate on the display that it recognized the 88k softdecoded file as MQA (“half-MQA”) and that it did the final unfolding. Possible, of course, that it did so anyway without indication…
But most likely, the result was negative.
It is possible, of course, that the process of capturing the stream damages the flags in some way.
Has anybody seen two-stage decoding?
I could probably test that…
Just tested it: Tidal desktop, USB into the Meridian.
Passthrough and exclusive: Meridian shows MQA 352 on that same 2L track.
Turn off passthrough, but leave exclusive to prevent any other software from messing with the stream: the Meridian shows PCM 88, no indication that it recognizes or decodes MQA.
The Tidal or other digital stream capture process is bit perfect.
I validated this by capturing an excerpt from Chris Isaak “Baja Sessions” on Tidal HiFi. The CD is HDCD encoded, and remarkably enough, the Tidal HiFi captured file was recognized and post processed as HDCD.
As for “flags,” the audio does not carry any S/PDIF subcode bits nor any metadata tags to indicate MQA. All MQA signaling is contained within the audio data itself.
If the Tidal software decoded file is not identified as MQA, that should not be due to the capture. It should be issue with the Tidal software decoding or the 2L encoding.
AJ
Or that my Meridian doesn’t actually have the second stage unfolding. I dates from the early era of MQA and I have not updated it, don’t even know if there is an update.
We will see if anybody else is successful, with a Mytek or Explorer. Or the coming Dragonfly update which explicitly claims this capability.
The Meridian 8x8 devices perform the 1st Stage Decode / Unfold to 2x rates…this [up to] 2x rate stream is then passed via Speakerlink and MHR to the DSP SE speakers…which in turn as a Renderer…and perform the 2nd and 3rd stage Unfolding to [up to] 8x rates [which is what most all of the 2L material is at]
And that is then why the MQA 352k display is seen on the DSP SE’s
This two stage / device process is similar to what happens if you have a Mytek Brooklyn / Explorer 2 receiving a stream from a Tidal app doing the 1st stage decode…i.e that the Renderer will perform the 2nd and 3rd stage unfoldings
Hm. I got a similar answer at the Meridian forum, but it doesn’t work like that, in my system.
I have tested it again. The software decoded material (both AJ’s 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.
This Confusion is frustrating.
Obviously the 8x8 is a FULL Decoder when outputting thru its own DAC…just as a Brooklyn or Explorer are full Decoders when using their own DAC’s
However, when outputting a DIGITAL Stream over Speakerlink and MHR, then it’s a different story, as the DAC is not being used in that scenario…and the 8x8 is passing a Digital 2x [24/96] stream over Speakerlink to the DSP SE’s downstream
This Decoder to Renderer method of fully decoding and unfolding an MQA track in the Digital domain is the way that the 8x8 and DSP SE’s work together to fully decode the MQA stream
It’s also best to remember that the 818 and 808 [and soon 218] essentially have TWO different paths for MQA to follow…Analog and Digital
When using its own DAC and outputting over Analog outputs…then the 8x8 will act as what MQA call a “Full MQA Decoder”, as per the diagram below
When outputting a Digital Stream, then the 8x8 will act as what MQA term as an “MQA Core”…while the DSP SE’s will as an “MQA Renderer” again as per the diagram below
All sounds reasonable.
When I’m playing MQA to the DSPs, this may very well be happening: there is no visible indication if it, but it’s a possible architecture. I can see why M would prefer not to send 352 over the MHR wire, but the engineering purpose of splitting it is not clear, if the Speakers can do the upper range, why not all.
But in the case of pre-decoded content, I definitely do not get the second stage indicated on the speakers. If you see that, any suggestions for what is wrong? Firmware upgrade for the speakers?
By what means are you passing data from the Tidal app to the 818??..Is it via USB??
When the Tidal app passes the partially decoded 24/96 stream to the Explorer 2 or Brooklyn, then the Explorer / Brooklyn will detect the presence of the MQA metadata and will then fully decode the MQA to the maximum output possible on the device…i.e. in this case, the Explorer / Brooklyn are acting as an MQA Renderer as per the diagram above
Just to be specific…if you use the Tidal app with Exclusive Mode ON…but MQA Passthru OFF…and output from Tidal to the Explorer 2, then the Explorer will light all all three lights [one blue and 2 white]…indicating that it is playing a 24/192 MQA Track [obviously this applies to the approx 66% of Warner content that unfolds to 24/192]
And the Explorer does this in spite of the fact that it is only receiving a 24/96 stream from Tidal, as that it is all it’s capable of
So, in a likewise fashion, your 818 should also display that it is receiving MQA data…and then display the Rate [2x, 4x or 8x] of the data in that MQA Stream when Fully decoded / unfolded
Perhaps your 818 needs a firmware upgrade to avail of this functionality??
Yes, I understand how it is supposed to work.
But it doesn’t.
I’ll look at firmware.
Sending 24/192 data over Speakerlink AES / EBU Balance Digital was always going to be a challenge…never mind sending 24/352 8x data!!
Set against that, I can see why Meridian have leveraged the existing Speakerlink cabling structure and kept the data transfers between the 8x8 and DSP SE’s to 24/96
It also enables partially decoded MQA 24/96 streams to be sent to the non-SE DSP’s over SPDIF and Speakerlink cabling…thus enabling those users to benefit from the High Res content and Time domain Deblurring of MQA tracks…all while waiting for Santa to bring their DSP SE upgrades 
There’s a detail hypothesis paper to support deeper understanding on the technical aspects of MQA. A must read!
2 Likes