MQA Automatic upsampling?

I have Audirvana 3.5.42 and an SMSL M500 (MQA Renderer DAC).

When I set the MQA parameter to MQA Renderer, the output of a Tidal MQA 44.1kHz (green) is a 44.1kHz stream. If I understand well, it means that the unfolded stream is a 44.1kHz one.
But when I I set the MQA parameter to Non-MQA, the unfolded stream is at 88.2kHz.
Is there an automatic upsampling or does that mean that the SMSL M500 does not do a correct unfolding?

Thanks for your answer.

M500 is full MQA decoder, so you need to set it to MQA decoder (not renderer) in the setting.

Hello @bitracer
Thank you. It is done.
The difference is still the same with MQA Decoder option : output is 44.1kHz while with “Not-MQA”, it is 88.2kHz…
That’s not annoying, I just would like to understand why, as I plan to change my DAC to an Non-MQA one…

That’s normal. If the DAC is not MQA capable, Audirvana does the first “unfold” and passes it to the DAC. That’s why you see 88.2KHz from 44.1 and you would see 96KHz from 48KHz.

OK I understand. The first unfold done by Audirvana streams 88.2 or 96kHz, as it is written in the MQA website (
But why, when I select MQA Decoder, it goes to 44.1kHz on the DAC? It is strange that the 2nd and 3rd unfold done by the DAC would “reduce” the encoding frequency no?

That’s because when your DAC is full decoder, the stream is passed to the DAC as is, and the DAC does all 3 steps.

From what I understand, what happens is that when the software or the Dac does the first unfold, it expands the audio “container” to 88.2 or 96khz to have enough room for all the frequencies; but that doesn’t necessarily mean that the actual audio data goes that high.

In Roon, the signal path is much clearer than in Audirvana. The MQA file has embedded data that tells the DAC that the original recording sample rate was 44.1 or 48 Khz, so that’s why once the unfolded “Hi-res” frequency goes through the DAC, it cuts/downsamples the output back to 44.1/48 Khz as “instructed” by the MQA codec since it’s the original frequency that the material was recorded/mastered in the studio.

That is, UNLESS there is actually higher frequencies compressed within the file, up to 192 Khz, so in that case, it would unfold further or stay at least in 88.2/96. But in most cases, I find that all those Tidal MQA songs are encoded in 44.1 or 48 Khz, with 24 bit. Just a few are actually real 96 Khz.

Hope this helps, and I hope what I understand, is correct :slight_smile:

Non are encoded in 96KHz. It’s either 44.1 or 48KHz. That‘s the whole point of the format. Play in CD quality with non MQA gear/software and better than CD if you have MQA capable gear.

Yes of course, but that doesn’t mean all the mqa’s have information to unfold to 96… If the original master is 44.1 or 48… the frequency will stay like that and won’t unfold higher, even if the “container” does. That’s why after the unfold, they resample back to 44.1/48.

That’s correct. The MQA won‘t unfold beyond original source resolution.