MQA, where is decoding done, what is required?

[danadam]

1) An MQA stream/file in a FLAC container enters a "DAC device" (not the same as a "DAC chip") through an input interface (eg, asynchronous USB).
2) A "GPP component" of the DAC device identifies the stream as a MQA, removes the container and exposes a raw MQA "PCM" bit-stream.

I'm pretty sure that decoding FLAC to PCM is always done on the host (i.e. your computer) and the only thing that's ever sent to a "DAC device" through an input interface is PCM.

Also, what does "GPP" stand for?

 

[Raindog123]

So which chip / IC really does the work before the DAC chip.

Try this:
SABRE DACs from ESS Technology to Integrate MQA Rendering

 

[ElNino]

Try this:
SABRE DACs from ESS Technology to Integrate MQA Rendering

That link just says that ESS is providing second unfold ("MQA rendering") support. If manufacturers want to provide the first unfold, they need to do this with additional hardware ("the first unfold, called Core Decoding, can be done on most DSP systems, and system designers looking to implement this can take advantage of standard code").

It's interesting that ESS didn't get flak from MQA for making it clear in this press release that there is no "third unfold". The MQA website is still promoting this fictional third unfold.

 

[Raindog123]

So which chip / IC really does the work before the DAC chip

....And if you eg google Dragonfly Cobalt DAC, you find that they use “ES9038Q2M [ESS Sabre] DAC chip and PIC32MX274 general purpose processor (GPP) chip right in front of it... Given, Dragonfly’s are MQA rendering-only “DAC devices”, so this PIC is not representative of the processor power needed for first unfold.

 

[Raindog123]

I'm pretty sure that decoding FLAC to PCM is always done on the host (i.e. your computer) and the only thing that's ever sent to a "DAC device" through an input interface is PCM.

Also, what does "GPP" stand for?

Thanks, I wanted to point out this is the beginning of the MQA processing chain. But yes, probably wrongfully assigned it to a “typical DAC device” itself.

GPP = general purpose processor

 

[Jimbob54]

Thanks, I wanted to point out this is the beginning of the MQA processing chain. But yes, probably wrongfully assigned it to a “typical DAC device” itself.

GPP = general purpose processor

[For the record, I am a RF communications/networking engineer, not a digital audio devices designer. So all my postings here are just _my_ interpretation of what I - like many others - read online and reimagining “how it could be implemented would I do it”.]

So, to conclude, to the general question of "where does the mqa decoding happen?" the answer is, of course, it depends!

Put another way, does it actually matter to the end user? Probably not. I am sure someone looking to include mqa in a hardware build (or software) will get relevant info from Bob & Co for relevant fees and NDA's

 

[mansr]

As I said, I'm interested in what is really used in "hardware" in a device that does not have an MQA capable DAC chip.
So which chip / IC really does the work before the DAC chip.

But contrary to what Bob Stuart writes about pure hardware solutions, they don't seem to exist in reality.
Apparently only ICs with computing power are used in front of the DAC chip, which then take over the unfolding via the appropriate software. That has nothing to do with a real hardware decoder.
So far I have not found a chip from MQA.

MQA "core" decoding is done on a DSP or microcontroller. They sell a decoder library for commonly used architectures including ARM and XMOS.

The "rendering" is done either by the same DSP/μC or, as with the Dragonfly, by setting a custom interpolation filter in the DAC chip.

 

[Roland68]

Thanks in advance to everyone who helped bring some light into the dark.

In the meantime I have also received an answer from MQA.
Unfortunately, you have confirmed what has already been answered here.

- The first unfolding to 88.2 or 96 kHz can take place in software (or in the MQA certified device) and can be used by every DAC.
- The next unfolding can only be done in the hardware of a MQA certified device
- This unfolding takes place in an existing processor or an additional processor in front of the DAC chip
- To fully unfold the MQA file, corresponding filters must also be activated in the DAC chip, depending on the MQA file and the DAC chip used

For me that means:
- Retrofitting a single device is hardly possible due to the complexity of the process.
- Expanding existing devices will only be worthwhile for a few manufacturers, since the costs and effort are not insignificant. Provided that the devices have the necessary hardware or can be expanded modularly.
- Unfortunately unsuitable for DIY enthusiasts and their own experiments.

Unfortunately, for me as an end customer, it is also not clear whether there are differences in the implementation of the MQA technology.

I will soon order a Gustard x16 and then look for a dealer who has another device with MQA and listen to both devices to form an opinion.

 

[gew55]

How do most people here playback the MQA files to there mqa DAC USB connection ?
Or can it be done with a multimedia player ?

 

[Beershaun]

You need a streaming endpoint that supports MQA and will pass it along via USB to your DAC. Roon on a PC or Mac is a popular choice or the Bluesound Node2i is another. I personally have only gotten it to work using my Dragonfly Red plugged into my Mac using the Tidal app locally, or using my LGV10 headphone out jack and again playing through the Tidal app on the LG phone.

It does NOT work with FireTV, Chromecast audio, or Raspberry Pi using Moode.

 

[Roland68]

How do most people here playback the MQA files to there mqa DAC USB connection ?
Or can it be done with a multimedia player ?

If you want to unfold the MQA file completely, it depends on your MQA device.

If your device is an MQA renderer, you need an MQA core decoder such as a hardware player with digital output, or streaming services or media players such as TIDAL, Xiami Music, Audirvana, Roon, etc.
It is important to note on which digital interface the MQA renderer accepts the MQA data.

For a device that works as an MQA full decoder, only the MQA file is required.
It doesn't matter from where this file is played, media player (software or hardware), memory card, etc.
Here, too, it is important to note on which digital interface the MQA full decoder accepts the MQA data.

 

[gew55]

If you want to unfold the MQA file completely, it depends on your MQA device.

If your device is an MQA renderer, you need an MQA core decoder such as a hardware player with digital output, or streaming services or media players such as TIDAL, Xiami Music, Audirvana, Roon, etc.
It is important to note on which digital interface the MQA renderer accepts the MQA data.

For a device that works as an MQA full decoder, only the MQA file is required.
It doesn't matter from where this file is played, media player (software or hardware), memory card, etc.
Here, too, it is important to note on which digital interface the MQA full decoder accepts the MQA data.

I bought a s.m.s.l SU-9 witch completely supports MQA on it's usb input.
I also have a media blu-ray player with 2 USB 3.0 connections but I think that this is only to hook up a hardrive or usb stick to play music or video from.
I was wondering wat the best solution is to hook up to my SU-9 usb input. I suppose it must be a computer or is a smartphone also possible ?

 

[Roland68]

I bought a s.m.s.l SU-9 witch completely supports MQA on it's usb input.
I also have a media blu-ray player with 2 USB 3.0 connections but I think that this is only to hook up a hardrive or usb stick to play music or video from.
I was wondering wat the best solution is to hook up to my SU-9 usb input. I suppose it must be a computer or is a smartphone also possible ?

What kind of DVD player is it? But the USB ports are probably only for storage media.
With a smartphone, it depends on whether it supports OTG and you need the right cable for it.
A USB-connected computer is the simplest, but there are many devices that can output digital audio via USB.[/QUOTE]

 

[ahofer]

Given how it operates, I find it hilarious that it is often the same people who say "How can you use (Roon or other) DSP, it absolutely ruins the sound - you must be deaf, I can't take you seriously" are somehow also the ones saying MQA is a big step forward.

DSP is only good when it is done in relatively underpowered hardware/FPGA, as opposed to using vastly greater processing power. Apparently.

sorry- recently had this thrown at me on FB, had to vent.

 

[mkawa]

A question from the op that should be easier to answer. How is mqa production done?

 

[earlevel]

Time resolution of 44.1kHz is in the order of picoseconds, so 1'000'000 times more than required.

It's actually even better than the Troll article says. Assuming the audio is dithered, the limitation is only due to being buried in the noise and being unable to determine the exact time of an event because you can't be sure if the suspected start time is signal or noise.

Which is to say, it's effectively the limit of your hearing ability—whether you can pick out the timing of something buried in noise. And of course, that has nothing at all to do with sample rate.

It is influenced by bit depth, but just to the degree that other noise doesn't interfere. So, probably 24-bit is no better than 16-bit in this respect, under normal conditions at least. It's probably also well-past cognitive ability as well, but yeah, the "time resolution" claim has no credibility, it's based on a lack of understanding.

 

[Island_Kenny]

my sense is that the MQA is a pure scam beyond the first unfolding, the 2nd unfolding is simply upsampling, and no one can explain what exactly the third unfolding do. And to only allow it on hardware only confirms my suspicion that it does absolutely nothing, as it is a lot more difficult to peek inside a microchip than to decipher lines of codes.

The bottom lines is that, for those Tidel subscribers who cannot tell whether MQA tracks played off Tidal is better or worse than CD quality tracks (me included), there is no reason to spend money on MQA hardwares.

 

[Roland68]

And to only allow it on hardware only confirms my suspicion that it does absolutely nothing, as it is a lot more difficult to peek inside a microchip than to decipher lines of codes.

It is a pure software solution that runs in a processor like XMOS, Atmel etc.

 

[ThatM1key]

I would like to add my 2 cents to this discussion. I think MQA can have potential but its a joke most of time.

Usually 44.1/16 MQA are just up upscaled CD's. Some 24/48 MQA albums do something with the extra breathing room but not that much.
Most MQA albums I've came across have terrible dynamic range compared to there CD counterparts. I know an album that sort of benefits from being unfolded: Chris Stapleton's Traveller.

Not Folded 24/48:

MQA Final Unfold 24/192:

*Recording using the EVGA NU Audio Card with the LG G7 Thinq(UAPP)

I believe the first fold of MQA should be free regardless of hardware. Charging for the 1st unfold is dumb. These USB MQA dacs I seen on the market still have crazy prices, I was almost thinking of getting one before hand. I would suggest getting a used LG G7, they go for $80~$130 used on ebay and it's still a modern phone. I hope somebody creates a MQA 1st unfold plug in for foobar2000 just like DVD-Audio, SACD and HDCD plugin. I'm almost certain that most MQA songs don't benefits from a 2nd to 3rd unfold anyways. I feel like MQA will die soon since other streaming use actual files above 24/48. I hope this helps with this discussion.

 

[Jinko_ITX]

To really benefit from MQA, you need good hardware and earphones or IEMs that is HiDef certified. Comparing songs over PCM and using MQA really does make a difference.