MQA and DSP Processing

This will of course conflict with hardware MQA decoding, requires full MQA processing upstream of the convolution.

“Convoluted” is a good summary of our whole system…

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Yes. I understand any DSP done in Roon (or any other application, including HQP) will interfere with hardware MQA. All the more reason to favour software decoding !

I tried Dirac with Meridian Explorer 2.
MQA Harware decoding wont work when using Dirac Asio Drivers.
Software decoding is ok.

HQP has some some mqa filters available. Using them in HQP via Roon and streaming some Tidal MQA files gives full MQA resolution with my IFI idsd dac. Listening results are mostly the same. I cant hear a notable difference.

HQP has some some mqa filters available. Using them in HQP via Roon and streaming some Tidal MQA files gives full MQA resolution with my IFI idsd dac. Listening results are mostly the same. I cant hear a notable difference.

I don’t believe this is true. The MQA filters are supposed to filter out MQA noise that’s present in an folded file. HQP does not offer MQA unfolding, and in fact, the creator does not like MQA.

Currently to get unfolded MQA to an IFI idsd dac, or any other non-mqa dac, you have to use Tidal directly in exclusive mode. Soon you will have Audirvana + as another option and eventually Roon.

After Roon offers MQA unfolding, then if you want, can further upsample using HQPlayer or probably Roon’s own upsampling to be offered in 1.3.

There is no unfolding.
I said you get a higher resolution.
Still soundwise to me its more or less the same.
I compared HQP/Roon/Tidal with Tidal App/Meridian Explorer. Later doing hardware decoding.

You wrote “full resolution.” To many, that would imply MQA decoding. HQPlayer is just filtering and upsampling MQA, not providing “full resolution” or even “higher resolution,” per se.

AJ

If you read question 65 here and the answers you will see how Bob Stuart sees MQA and DSP working. Sorry I could not cut and paste the section here without it looking a mess and being difficult to read.

http://www.computeraudiophile.com/content/694-comprehensive-q-mqa-s-bob-stuart/

Using the Tidal App and the Meridian Explorer2 you get this nice blue bright light on the DAC when he is decoding MQA.
You get conditioned like a Pawlow Dog on that light because now you know you hear the “good and real” stuff.
I bypassed the software decoding to be sure to get to the “real” blue light, the MQA Nirvana.
Results to my ears where really good, surprisingly so to me.
I happen to have at my disposal toys like HQP, Roon and a DAC with a possibility to decode up to 768 kHz.
The creator of HQP, Miska, did a lot of work and writings about MQA and so I tried with them to get as close as possible to that “blue light experience”.
And my ears tell me that this setup I found is close, for me close enough.
But allright, I miss the “blue light” and my Pawlow conditioning wants to see that.

Phew - for a minute there I started worrying that either a new MQA topic hadn’t started up yet today, or I’d somehow missed it if it had. Now I can relax. :innocent:

On a more serious note, I’d be interested to hear from Roon on this. I imagine they’ll be able to tell us something more concretely once they’re actually doing MQA decoding and have worked it all out themselves with Meridian. I mean MQA.

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Don’t you think the end result will be the same? i.e. a degraded MQA signal ?

Just pulling out the flowchart from Bob’s answer, it would appear that as long as the software doing the decoding (decoder 1) inserts the DSP after the decoding but before sending to the DAC for its final hardware MQA voodoo (decoder 2), then everything should be good.

He mentions a side-chain API in his description of the flowchart (quoted below), no idea what that really means.

We are going to answer this question by describing the optimum structure for MQA in a surround processor (e.g. using upscaling, matrixing, room correction) or in an automobile or a DSP loudspeaker. Such processing may not be performed on the incoming MQA (as this would destroy the MQA data signals) and should not be performed on the final output to the DAC (as this would compromise the MQA decoder’s management of the DAC), introduce uncontrolled temporal blur and require a lot of resource to perform, e.g. room correction at 8x or higher DAC feed speeds. 12

The main decoder produces an intermediate signal and processing, such as multichannel up-mixing, room correction or crossover, etc. may be performed on this. A software decoder may include a side-chain API where such processing can be inserted, as it is already in mobile implementations.