MQA on all iFi devices. AND on ANDROID!

[mansr]

Is this a full MQA decoder, render only, or both?

[mansr]

1 hour ago, AMR/iFi audio said:

Hopefully this is all clear now.

As mud. The only rational explanation I can think of is that a firmware including both DSD512 and MQA support wouldn't fit in the XMOS flash memory. If that is the case, why not just say so?

[mansr]

8 minutes ago, AMR/iFi audio said:

The actual reason is that to implement MQA, digital processing is implemented as well and this consumes resources during runtime even in bypass mode (read: no MQA stream playing).

Would it not be possible to disable all MQA related processing at the highest rates?

[mansr]

29 minutes ago, crenca said:

Perhaps not. Is this evidence that MQA is processing your PCM and DSD no matter what you do? Does the architecture of MQA require the DAC manufacturer to allow in MQA to be doing something, essentially on all the time?

There is no technical reason for such a requirement.

[mansr]

7 minutes ago, crenca said:

I think it probably does answer your and mine and @mansr question,

Nope.

 

7 minutes ago, crenca said:

in that the new code by accommodating new functionality (MQA), no longer has the ability to do DSD512.

Yes, that's the result. Some of would like to know why.

 

7 minutes ago, crenca said:

Perhaps it is not MQA directly - only the new code was not optimized to the same extant...different goals, maybe even different coders, etc.

We've been told that the problem is that the MQA code, for reasons unknown, insists on always doing some unspecified processing, even with non-MQA input, and this processing cannot be disabled, ever. If it could be disabled, then doing so for high-rate inputs (which can't be MQA anyway) would solve the lack of processing resources.

[mansr]

51 minutes ago, crenca said:

I wonder if that is not a "layman's" explanation, as it were.  In other words MQA is just fat code and working it in is inelegant, and iFi only had limited man hours, etc.

 

IF it is really truly always processing, then we are back to the important question as to what, exactly, is it doing and why, and what it means for our PCM/DSD.

I intend to find out exactly what it does. Hooking up the logic analyser right now.

[mansr]

10 minutes ago, AMR/iFi audio said:

No, this is not how MQA works on a firmware level in XMOS. Not at all.

That's terrible. Either they're plain incompetent, or they've intentionally made it as difficult as possible to avoid their meddling.

[mansr]

On 4/7/2018 at 6:19 PM, mansr said:

I intend to find out exactly what it does. Hooking up the logic analyser right now.

Here's what it looks like:

 

Yeah, no warranty here.

[mansr]

Ugh, the MQA impulse response clips for several of the filters.

[mansr]

Well, the good news is that non-MQA playback uses the built-in filters of the DSD1793 chip as before, at least on the Nano (original silver). There are, however, some slight differences, probably unrelated to MQA, in the configuration sequence sent to the DAC chip. Watch out for pops when starting DSD playback.

[mansr]

1 hour ago, rwdvis said:

On 3/31/2018 at 10:52 AM, AMR/iFi audio said:

The MQA filters are in use ONLY run when MQA files are passed through and vice versa.

Are you absolutely certain about this?

I checked the behaviour of the Nano (silver). The DAC chip is configured exactly the same as with firmware 5.20 for non-MQA playback. I don't have any other iFi products, but I have no reason to believe they'd be different.

[mansr]

11 minutes ago, AMR/iFi audio said:

Please review MQA's website for more details then.

Very funny.

[mansr]

7 minutes ago, AMR/iFi audio said:

This has nothing to do with MQA.

The MQA resampler clipping has everything to do with MQA. I have never before encountered a resampler that clips on a single-sample full-scale impulse. It may not be likely to occur with music, but why take the chance?

[mansr]

11 minutes ago, AMR/iFi audio said:

13 hours ago, mansr said:

There are, however, some slight differences, probably unrelated to MQA, in the configuration sequence sent to the DAC chip. 

The end-result of how the chip is configured is the same.

Yes, the end result is the same. However, with the new firmware, the headphone amp is unmuted before the DAC is configured as opposed to after with firmware 5.20. This sometimes results in a pop or click.

[mansr]

Switching between MQA filters also causes some nasties:

 

As does switching from non-MQA to MQA:

[mansr]

45 minutes ago, zacster said:

I'm running my iFi Nano iDSD with a Raspberry Pi running volumio, and streamed music from Audirvana over DLNA.  I'm finding the beginnings and ends of tracks being cut off on MQA.  Other formats seem to be fine.  I'm not getting smooth transitions on what should be gapless tracks. Any advice?  

That's expected with MQA. Complain to Bob Stuart.