WiiM bit perfection vs former Tidal's MQA

[merifon]

Disclaimer: this isn't a post upon MQA, nor about its lossyness, it's about how WiiM devices manage files they sent over their digital output.
Premise: Tidal since time has replaced its MQA 48KHz 24bit derived from hi-res master, with hi-res Flacs. The remaining MQA derived from CD quality masters (RedBook), delivered in 44.1KHz 16bit, have been left untouched, just the labels MQA's have been removed from playing apps. This make sense, since their PCM content (differently from the hi-res derived) was the same of cd version with just some identity flag added.
Before the Tidal change, my WiiM mini delivered to my Nad C3050LE, signals that its inner Bluos dac recognized as MQA and decoded. Obviously, any little signal modifications (volume and PEQ) avoided such recognition and signals were processed as standards Flacs.
When the MQA first unfold was removed from WiiM app, following the formal dismissal of MQA by Tidal, no more MQA recognition happens.
This could appear normal if the same former 44.1KHz 16bit files, played directly with the bluos inner streamer of the NAD, wouldn't still recognized as MQA and decoded.
The question is: if WiiM doesn't change anything of the streamed files and bit perfection is claimed, why those files aren't recognized as MQA as happening before?
I got an MQA CD for test and even the toslink pass through of my other WiiM Pro, seems remove something, since in that path, MQA recognition disappears.

 

[BEE]

Good question, I see on the WiiM website faq for the Ultra it shows as able to play from MQA.

In theory as you surmised a bit perfect signal should still be able to pass through MQA, I would log a support ticket for an answer.

 

[hgo58]

Disclaimer: this isn't a post upon MQA, nor about its lossyness, it's about how WiiM devices manage files they sent over their digital output.
Premise: Tidal since time has replaced its MQA 48KHz 24bit derived from hi-res master, with hi-res Flacs. The remaining MQA derived from CD quality masters (RedBook), delivered in 44.1KHz 16bit, have been left untouched, just the labels MQA's have been removed from playing apps. This make sense, since their PCM content (differently from the hi-res derived) was the same of cd version with just some identity flag added.
Before the Tidal change, my WiiM mini delivered to my Nad C3050LE, signals that its inner Bluos dac recognized as MQA and decoded. Obviously, any little signal modifications (volume and PEQ) avoided such recognition and signals were processed as standards Flacs.
When the MQA first unfold was removed from WiiM app, following the formal dismissal of MQA by Tidal, no more MQA recognition happens.
This could appear normal if the same former 44.1KHz 16bit files, played directly with the bluos inner streamer of the NAD, wouldn't still recognized as MQA and decoded.
The question is: if WiiM doesn't change anything of the streamed files and bit perfection is claimed, why those files aren't recognized as MQA as happening before?
I got an MQA CD for test and even the toslink pass through of my other WiiM Pro, seems remove something, since in that path, MQA recognition disappears.

The bit perfect pass though is for PCM encoding only. Originally WiiM did have a MQA passthrough option. This is no longer there.

The MQA passthrough option was removed or deprecated around mid-to-late 2024, aligning with Tidal’s shift away from MQA

 

[merifon]

There must be something subtle, in the coaxial input of Nad there is a "MQA pass-through" that if disabled, stops the MQA recognition.
Maybe I'll follow your suggestion and open a ticked but I wouldn't like to disturb with a minor problem that is mainly curiosity.

 

[merifon]

The bit perfect pass though is for PCM encoding only. Originally WiiM did have a MQA passthrough option. This is no longer there.

The MQA passthrough option was removed or deprecated around mid-to-late 2024, aligning with Tidal’s shift away from MQA

I could think that at WiiM labs, they thought Tidal would replace all MQA files, not only those 48KHz 24bit. Or maybe was royalties matter only.
I agree, it's a non-problem for the majority of the people but (maybe due to some biases), I feel that the D/A process done by the MQA circuit on those files, is slightly better than the other standard dac, at least for my C3050LE. A different process path is involved and maybe for other models, could be true the opposite.

 

[merifon]

Addendum
Thinking about how MQA buries its flags on few less significant bits (six for 24bit files and not clear how many for 16bit), it's possible that without a "licensed" step that searches for them and rises a flag, the simple "file passthrough" doesn't trigger the process

 

[merifon]

As far I could found, regarding materials from hi-res masters, then encoded in MQA 48KHz 24bit, the part up to 22KHz is left untouched whilst the ultrasonic part is heavy lossy compressed, using the six less significant bits from 24. For files delivered in the 44.1KHz 16bit MQA form, I didn't find reliable informations. Besides it's true or not that the first unfolding could really extract totally untouched pcm up to 22KHz, the use of a dedicated dac stage, at least for upsampling and antialias filtering is quite sure. As example, when MQA is triggered, in my Nad I loose some audio controls, suggesting is involved a different audio process.
I must add that the lack for informations from Carver and Co. and the "mystic aura" they wanted to give, didn't help to acceptance. In today's era of big bandwidth, reducing size of file it's not a main advantage, whilst the custom antialias filtering process could still make sense.