I need a signal path explanation with this MQA

[macaumetal (Gustavo Girves)]

Hi, maybe you can help me understand what is happening on these steps.

I see the file is 24/48, but Roon decodes the MQA Core to 96khz and then takes it back to 48khz.
Am I interpreting this right? Just trying to understand, thank you!

[Rugby (aka Daniel or Big Dan)]

Well, sort of. Roon’s involvement with the audio file ends when it hits AudioQuest Dragonfly Cobalt. Everything after that is the Dragonfly’s processing. Roon is just showing you what the Dragonfly is telling Roon that it is doing.

So, Roon is sending the Decoded file which when it hits the Dragonfly is 24/96. The MQA rendering instructions are telling the Dragonfly to render it down to 24/48 because that is the Original Source Rate.

[macaumetal (Gustavo Girves)]

Great!! Thanks!

[Carl]

@Rugby

The MQA rendering instructions are telling the Dragonfly to render it down to 24/48 because that is the Original Source Rate.

Well, not quite…

The MQA signalling is telling the Dragonfly that the OrFS (original frequency sampling rate) was 24/48 … it’s not an instruction to force the DAC to downsample … it’s used to advise the DAC so that it can select the appropriate digital filter when rendering (based on the OrFS of the source and the DACs internal capabilities).

[macaumetal (Gustavo Girves)]

@Rugby

Roon is sending the Decoded file which when it hits the Dragonfly is 24/96. The MQA rendering instructions are telling the Dragonfly to render it down to 24/48 because that is the Original Source Rate.

So the decoding to 96 24with MQA signaling part only shows what the DAC is “capable”, then it’s informed of the ORFS and then decodes?
Pardon my simplicity but I’m trying to decode the info

[Carl]

@macaumetal

So the decoding to 96 24 with MQA signaling part only shows what the DAC is “capable”, then it’s informed of the ORFS and then decodes?

No… try this explanation…

MQA streams are always decoded to x2 rate (88.2/24 or 96/24) this is the first unfold.

The decoded x2 rate stream (MQB) is then sent to the DAC for rendering.

If the DAC supports MQA it then uses the MQA signalling information within the stream to select the right MQA rendering method (often called the second unfold) .

This rendered signal is the sent to the DAC chips within the device.

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

Unless it’s 44.1/88.2

[Carl]

@Jim_F,
Correct I should have said to x2 rate … post now adjusted.

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

Not sure about this.

[Carl]

@Jim_F,
Looks fine … it’s still MQA decoding to x2 rate.

Don’t confuse OrFS with the actual rate of the stream.

[wklie (Peter Lie)]

@macaumetal

takes it back to 48khz

The OrFS refers to the sample rate of the master used to produce this MQA music. Your DAC is not downsampling it.

[joel]

Linking to this again…

MQA 44.1kHz and signal path?

There are four different rates here, which causes no end of confusion: The MQA container rate (i.e. 44.1k or 48k) which is how the MQA gets to you. It has nothing to do with anything else and has no bearing on rendering rates. The transport rate of decoded MQA (“MQA Core”) from the MQA decoder to the rendering part of a DAC. This can be from Roon (or any other MQA decoder) to the DAC, or within the DAC itself. MQA Core is always 2x rate (88.2k or 96k) and has no bearing on rendering rates. T…

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

It’s still a little confusing to me. What are we actually hearing? I have a Dragonfly rated MQA 24/96 and a Meridian Prime rated MQA 24/192. I have Tidal that has 24/44.1, 24/48, 24/88.2, 24/96, 24/192 and even 24/384.

[wklie (Peter Lie)]

The MQA 96kHz and 192kHz ratings are for individual tracks, not DAC. Your DragonFly is also capable of playing MQA 192kHz tracks, as with any certified MQA DAC.

You’re hearing music rendered in a way that optimizes for specific characteristics deemed important by MQA Ltd.

If you’re asking at what sample rate the rendering occurs, that’s DAC specific and not usually public.

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

I don’t know what any of that means. My MQA DAC’s are 96 and 192. Is that what I’m hearing unless the tracks are lower resolution?

[wklie (Peter Lie)]

@Jim_F

My MQA DAC’s are 96 and 192

Where do you see these?

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

In their written specifications. Are you saying all MQA DAC’s can play whatever resolution the track specifies and we can’t know what that is? That doesn’t seem right.

[wklie (Peter Lie)]

You cannot equate PCM rates to MQA master sample rates.

Even if the USB interface of DragonFly is limited to 96kHz, it is sufficient for playback of MQA 192kHz tracks and MQA 384kHz tracks, because those MQA rates refer to the masters used for production, not necessarily the DAC playback rate, and definitely not the interface requirement.

[wklie (Peter Lie)]

@Jim_F

Are you saying all MQA DAC’s can play whatever resolution the track specifies

Yes.

@Jim_F

we can’t know what that is

You can only know that MQA Ltd. certifies a DAC to play a track in the best possible manner.

[Jim_F (- Search, Read, Comprehend, Reboot, Post)]

That implies that all MQA DAC’s are the same.