MQA Users & Discussion Thread

[Guest Sime]

@@Eggcup The Daft I'll get that file later on and try it. And yes, there are no settings within the Bluesound universe to allow frequency adjusting.

Edited June 4, 2016 by Sime

[Guest Sime]

@@Eggcup The Daft the Piano piece is being decoded ar 44.1.

[davewantsmoore]

So I should hunt down a 192 and see what it does or do you know it'll be 96? @@davewantsmoore

 

"192 original rate", MQA will be in a 48khz container...   I don't know what it will play back at for you .... but if you told us what it played back it, I could tell you what the possible reasons were.

 

 

@@Eggcup The Daft the Piano piece is being decoded ar 44.1.

 

This is telling.    The is no oversampling happening  .... so if the Bluesound isn't oversampling 2x, like was suspected....   Then how come the other 24/44.1 PCM files were playing back at 88.2khz ??

 

I do love a good mystery.    The only explanation I can come up with, is that the MQA is being decoded (which would explain the blue light), and either:

 

• Being rendered by the MQA decoder at 88.2khz (instead of the 352.8khz contained in the file).   This is quite possible... it's one of the features of the MQA decoder - it can be told to render at a lower rate, for whatever reason (eg. device support etc.)

OR

• Being rendered by the MQA decoder at 352.8khz, and then being downsampled by the Bluesound to 88.2khz before going to the digital output.    This downsampling is in theory undesirable  (it is the whole point of what MQA is trying to avoid)

AND

• The person being quoted earlier from Bluesound, either poorly understands things, or is a poor communicator, or both.

Edited June 4, 2016 by davewantsmoore

[SilverPS3]

He said he would listen.  I doubt we would be reading the listening notes any time soon.

 

 

[gcgreg]

Based on how the origami was explained (which may not be exactly how it technically works, I don't know that detail), it appears as if the Bluesound is "unfolding" the MQA once and outputting the resultant PCM. The odd thing is that it natively supports double those sample rates, why not unfold the next portion and serve 176.4? Could it lack the necessary processing speed perhaps?

[davewantsmoore]

Could it lack the necessary processing speed perhaps?

 

Yes, that could be the reason.    Although it seems to be able to render the MQA at 352.8 for its analogue outputs (implying it does have enough).    The implementation of the MQA decoder in the Bluesound can be told to do whatever they want it to do.     It could be limiting the digital output(s) to <=96khz to allow the toslink output to work, for example.

[Guest Sime]

It's 192 out of its toslink for standard hires stuff.

Edited June 5, 2016 by Sime

[davewantsmoore]

Have you reposted a question for Bluesound?   I'd be interested to know what their explanation is for:

 

MQA light is on, using digital output to outboard DAC which does not oversample input data

 

352.8 source (44.1khz container) = DAC receives 88.2khz

44.1 source (44.1 container) = DAC receives 44.1khz

96 source (48khz container)  = DAC receives 96khz

 

 

... or LMK if the above examples aren't the result you got  (cos that means I got confused).

[aechmea]

 It could be limiting the digital output(s) to <=96khz to allow the toslink output to work, for example.

 

Yep, or it could be that the record companies don't want unfolded and preprocessed hirez PCM to escape into the wild where it would be dead easy for everyone and anyone to become a 'pirate'.

 

I bet that the only fully and properly processed data will only ever be available via the analogue outputs which is what switches the blue light 'on'.  Digital outputs from SACD, HDCD and DVD-A are all digitally hobbled; why would MQA be any different.

[Guest Sime]

Have you reposted a question for Bluesound?   I'd be interested to know what their explanation is for:

 

MQA light is on, using digital output to outboard DAC which does not oversample input data

 

352.8 source (44.1khz container) = DAC receives 88.2khz

44.1 source (44.1 container) = DAC receives 44.1khz

96 source (48khz container)  = DAC receives 96khz

 

 

... or LMK if the above examples aren't the result you got  (cos that means I got confused).

Your correct.

[Guest Sime]

@@davewantsmoore I posted it over there, but they are sketchy on what they do and don't reply to.

[davewantsmoore]

Yep, or it could be that the record companies don't want unfolded and preprocessed hirez PCM to escape into the wild where it would be dead easy for everyone and anyone to become a 'pirate'.

 

Then they won't release content on the MQA format, as there is nothing inherent to the format to prevent this.

[Guest Eggcup The Daft]

I'd still guess that the 352.8 file is being downsampled by the Bluesound to something it can output, and that 88.2 is the best it can do alongside the MQA processing without stuttering or falling over.

[Guest Sime]

When I try to play a standard 352 track (non-mqa) it downsizes it to 192 but stutters.

[Guest Eggcup The Daft]

When I try to play a standard 352 track (non-mqa) it downsizes it to 192 but stutters.

My guess is that they are reducing the MQA further to where it works - quality control on the part of MQA, who aren't going to have stuttering tracks associated with their shiny new format...

[davewantsmoore]

I'd still guess that the 352.8 file is being downsampled by the Bluesound to something it can output

 

Perhaps.... Although, I'm skeptical.    Doing this would defeat one of the major features of MQA, which is to avoid (low quality) sample rate conversion.

 

The "MQA way", would be to have the Bluesound render the MQA directly to 88.2khz (if that's the output sample rate Bluesound wanted to use) ... and not need to do any "sample rate conversion".

 

 

When I try to play a standard 352 track (non-mqa) it downsizes it to 192 but stutters.

 

Wow.  That's not very smart of them.   They should be converting it to a multiple of 44.1khz   (eg. 176.4)

[Guest AndrewC]

He said he would listen.  I doubt we would be reading the listening notes any time soon.

 

Yeah, I was wondering the same thing when I read his coverage ;-) Such extensive measurements, but not a single word from him on how it sounds, and it’s own recordings!

 

My guess is JA is going to hedge his bets and not be so over-the-top about MQA like TAS, especially given the recent scandalous piece by AD (presumably against TAS and other WebZine’s) over their unethical review methods. I think JA will be looking to tone-down any pro-vendor pitches ;D

 

 

Interesting... Meridian is never a supporter of DSD, given the recent uptake of DSD downloads, they have no choice to make their product more competitive? There's a review of Meridian Explorer and MQA playback. Looks like MQA decoding on Explorer have trouble in achieving 24-bit resolution while PCM version 24/192 and DSD64 has the lowest noise in the audible range!

 

 

http://archimago.blogspot.sg/2016/02/measurements-impressions-meridian.html

 

Actually, very few DACs delivery 24 bit resolution, meaning resolution as measured (not datasheet spec) by the likes of Stereophile etc., even the very best DACs have been measured at around 19-to-21 bits at most.

 

That said, IMHO, it makes no sense to have a “next generation” format that is lossy, even if for only the very highest ultrasonic octaves. MQA justifies this via an explanation in the ’14 AES paper http://www.aes.org/e-lib/download.cfm?ID=17501 … to paraphrase, they basically say “we measured the last 60 years of recordings, none have resolution/noise-floor wider than 20bits PCM, so that’s good enough.” ::)

 

MQA is not progress for the Audio industry.

[tane0019]

Cheaper alternative to Meridian MQA

[embed=600,400]

[/embed]

[MusicEar]

http://www.stereophile.com/content/inside-mqa-manufacturers-comment#HDraW96o0ZqfWlDZ.97

 

Why is run-out noise shot up so abruptly as the frequency response goes down for a decoded MQA? Also, compared with original WAV recording, the noise of decoded MQA is much higher. It looks to me MQA noise floor can only achieve 20-bit of resolution in the audible range despite outputting 24-bit data to the DAC. Such abnormality happens in the audible range and it does play a part in alternating the sound quality of the original WAV recordings.

 

 

[Guest AndrewC]

http://www.stereophile.com/content/inside-mqa-manufacturers-comment#HDraW96o0ZqfWlDZ.97

 

Why is run-out noise shot up so abruptly as the frequency response goes down for a decoded MQA? Also, compared with original WAV recording, the noise of decoded MQA is much higher. It looks to me MQA noise floor can only achieve 20-bit of resolution in the audible range despite outputting 24-bit data to the DAC. Such abnormality happens in the audible range and it does play a part in alternating the sound quality of the original WAV recordings.

 

While these are very low-level signals (-96dB peak), I have to agree, it’s pretty lousy noise floor for a non-decoded MQA signal. With this response, Stuart has validated 3rd party reviews that say MQA scews-up original tracks when not decoded to MQA.

 

In other words, if your DAC doesn’t support MQA, you’re basically fcuked if your sources are all MQA encoded files or streams ;D

 

 

The noise of MQA decoded signal is not higher than the original WAV though… where did you see that it’s higher? (don’t mistakenly compare to dither noise floor references).

 

[MusicEar]

Yes, the decoded MQA followed closely to the original WAV but it seemed to me MQA can only deliver up to 20 bit and not PCM standard of 24 bit resolution. The best converters out there can easily do 22 bit. FLAC and other lossless codecs are capable of doing 24 bit way before MQA. Why limit?

[Guest AndrewC]

Yes, the decoded MQA followed closely to the original WAV but it seemed to me MQA can only deliver up to 20 bit and not PCM standard of 24 bit resolution. The best converters out there can easily do 22 bit. FLAC and other lossless codecs are capable of doing 24 bit way before MQA. Why limit?

 

We're going round in circles a little... as I said before, you’re talking about technical spec (24bit)… whereas MQA is referencing general DAC output performance, not spec, when they say 20bit PCM resolution is “good enough”. As you yourself state, “the best” can do 22 bits today... but IMHO not “easily” - care to qualify your statement? Which DAC manufacturer(s) does "easily" 22bit of actual [Edit] measured output resolution?

 

But we’re on the same page, I think it’s a sham for MQA to offer  such “average” performance in this day and age.

[Guest AndrewC]

Yet another gushing MQA report…

 

http://www.tonepublications.com/review/why-mqa/

 

What gets me is this part about undecoded listening…

…

In addition, files encoded with MQA will still sound better, cleaner on your standard digital setup even if you don’t have a DAC capable of decoding MQA. For now, let’s call the difference about 20% in terms of revealing more music in a less imposing (i.e. digital artifacts, etc) way than a non-MQA file.

…

 

If the tracks are being specially handled as part of the MQA encoding process, naturally they’re going to sound good even non-decoded… Just like XRCDs sound much better than normal redbook releases of the same album. So, not sure what the fuss is ::)

 

 

Just noticed that last week BlueSound announced firmware update to support MQA on their platform;

http://www.bluesound.com/news/2016/mqa-now-available-on-bluesound/

 

[embed=425,349]

[/embed]

 

 

And Highresaudio has started selling MQA encoded music; https://www.highresaudio.com/studio_master.php?fids=153&cr=MQA

 

Almost nothing but Classical… What a drag :P

[Guest AndrewC]

Just delivered to my office in time for some weekend MQA Exploration ;D

 

 

[InnocentBlood]

what MQA music did you end up getting to test the Explorer2 with?