Mac AIR v MiND 180 v Auralic ARIES v totaldac d1 server

[Jwg1749]

Where I differ a bit with "Confused" is his conclusion that the Totaldac clocking ability is superior to AIR. Surely it is just audibly different to two individuals' sets of ears in a way which pleases them!

Actually I would have to stick with a conclusion that the Totaldac may have superior clocking ability. The fact is I have never listened to a Totaldac D1, and hearing is believing for me. However, looking a some of Guillaume's and Rufus' previous posts, it is clear that they think that they are hearing a most definate improvement, i.e. they sound like they are a little beyond the subjective range. As I mentioned, I would need to hear one myself before stating anything more than a tentative "may have".

Please excuse me if I go into pedantic mode for a while. (Maybe that should be a given )

Guillaume and Rufus clearly agree that the Totaldac d1 server sounds better than AIR, and I certainly don't doubt their judgement. But in the absence of measurement that is by definition a subjective judgement. That being the case I don't think one can or should conclude from their comparison that the Totaldac is providing technical (objectively measurable) improvements over AIR, for example in the area of clocking. It may or may not be measurably different but the subjective improvement in sound quality does not necessarily means it's technically better than AIR - "lower jitter", "more bit perfect", however you might interpret those terms.

I think this is right. One thing is absolutely clear: the jury is still out.

Has anyone tried recording the various inputs (Totaldac via AES/EBU, or AIR) using the Devialet's USB out? You could then null the resulting files using Audiodiffmaker, which would provide an objective measure.

[thumb5]

If clocking is the main reason for the difference in sound between AIR and Totaldac AES/EBU and both mechanisms provide bit-perfect data to the DAC then the implication is that Devialet's buffering and re-clocking of AIR-transported data is sub-optimal. If so, I'm very surprised that Devialet would have made that compromise given that AIR is one of their flagship technologies. And it sounds pretty good to me anyway

One key difference between AIR and AES/EBU (as I understand it, please correct me if I'm wrong) is that with AES/EBU, the source (e.g. Totaldac d1) encodes the data stream using its own clock and the Devialet has to extract the clock from the data stream. I'd assume it then has to either drive its own audio playback pipeline completely from the recovered clock, or somehow re-clock/re-sample the data to synchronise it with its own internally-generated clock. For what it's worth, my guess is the latter case. Although the two clocks should of course be nominally running at the same rate, over a long-enough time they will necessarily drift because neither of them can be completely accurate/stable. This clock synchronisation process might introduce subtle changes to the data stream - who knows?

Another factor is that the AES/EBU interface has limited error detection but essentially no mechanism for error correction. These AES/EBU guidelines suggest in section 3.8 that a DAC detecting errors in an AES/EBU input stream should handle them by interpolating between valid samples, or by muting its output. Needless to say, neither of these can be considered "bit perfect" activities. I've also seen this referred to as "error concealment" rather than error correction.

With AIR, by contrast, the Devialet can correct errors in incoming data (by having the host computer retransmit them) and it can clock samples out of the AIR buffer into its audio pipeline using its own internal clock. There is no need for clock recovery because the incoming sample data are implicitly delivered at the Devialet's own internal clock frequency. There is a closed-loop feedback mechanism between the Devialet and the host to handle small differences between the rate at which the host generates samples and the rate at which the Devialet plays them, hence there should be no need for the Devialet to re-sample for clock synchronisation.

It's no stretch of the imagination for me to believe that the complete path from the input of AIR (output from iTunes, Audirvana, etc.) through to the point where samples get into the Devialet's audio pipeline (i.e. start following the exact same path as input from USB, AES/EBU, etc.) can be completely error-free - bit-perfect, if you prefer.

So it seems to me that there are grounds for considering AIR to be a technically optimal solution to the streaming problem.

As always, subjective judgements of sound quality can and should continue independent of the technical discussion...

[GuillaumeB]

As always, subjective judgements of sound quality can and should continue independent of the technical discussion...

Spot on Ian

Guillaume

[philoouu]

One key difference between AIR and AES/EBU (as I understand it, please correct me if I'm wrong) is that with AES/EBU, the source (e.g. Totaldac d1) encodes the data stream using its own clock and the Devialet has to extract the clock from the data stream. I'd assume it then has to either drive its own audio playback pipeline completely from the recovered clock, or somehow re-clock/re-sample the data to synchronise it with its own internally-generated clock. For what it's worth, my guess is the latter case. Although the two clocks should of course be nominally running at the same rate, over a long-enough time they will necessarily drift because neither of them can be completely accurate/stable. This clock synchronisation process might introduce subtle changes to the data stream - who knows?

Another factor is that the AES/EBU interface has limited error detection but essentially no mechanism for error correction. These AES/EBU guidelines suggest in section 3.8 that a DAC detecting errors in an AES/EBU input stream should handle them by interpolating between valid samples, or by muting its output. Needless to say, neither of these can be considered "bit perfect" activities. I've also seen this referred to as "error concealment" rather than error correction.

Hello thumb5
This is very interesting. Then it is hard to imagine how using two clocks in a row could produce a better sound than using only one since the beginning of the process.

As always, subjective judgements of sound quality can and should continue independent of the technical discussion...

Agree

[IanG-UK]

What will be illuminating is the time when (and if) Devialet introduce a source component and therefore effectively manage (if you buy into and are able to use SAM) the chain from CD/download "in" through to sound "out".

As far as I know, in their own independent demonstrations, Devialet have always used iTunes/Mac - perhaps there was also Qobuz at Munich this year - so they either think:

1 iTunes/Mac is perfect or good enough even by Devialet standards (and "perfect" would be pretty unusual for a mass market product); or

2 They thought that way originally and do not want to step away from that position now; or

3 Commercially, in their judgement, that is optimal; or

4 They don't want to endorse rival manufacturers' products; or

5 They are working on their own source component.

I hope the answer is 5. but my money would be on 1./3. - I suspect Devialet's big investors want their real efforts put into exploiting SAM and particularly ADH in much wider markets.

[Confused]

Ian - Perhaps someone should take these queries to the Guilford Audio event in October. (I doubt they will get a sensible answer though)

[IanG-UK]

Hi Confused

I may go as Devialet will be there - but my money is on your last phrase - they never give anything away (quite rightly, commercially, I guess). Rather like Quad used to be.

[GuillaumeB]

Ian - Perhaps someone should take these queries to the Guilford Audio event in October. (I doubt they will get a sensible answer though)

There's nothing wrong with AIR, well apart from the odd dropouts and the white noise problem. OK the white noise thing is pretty bad but from what I can see it's not happening to that many people.

So I don't see why they should develop a new source product or endorse anyone else's for that matter.

They'd be better off working on a mini 120 - a 60 even! Price it around £2-3k (or less even) and blow a hole in the competition's sales. Perhaps it could even include HDMI inputs so that it could be used as a home entertainment hub, connecting TV, Sky box etc.

Linn produce such a product: the Majik DSM which is their biggest selling product. It combines streamer, pre and power amps and has inputs from all my boxes (blu-ray player, Sky, Apple TV). I have one in my living room, it's rather good actually though not a patch on Devialet SQ. Now imagine that with ADH and SAM! And a decent remote for the living room.

I think this kind of product would give Devialet a much wider market, let's face it the hi-fi world is pretty small.

Guillaume

[ThierryNK]

Hi Guys

For some unknown reasons, maybe some cable somewhere , I stopped receiving notification mails for this thread…

I have retrieved some web links about "computers make mistakes in audio" which is one of my favorite subject and is the reason of so many disappointments and astonishments...

http://www.audiostream.com/content/qa-jo...at-digital

http://www.audiostream.com/content/qa-jo...-just-bits

http://www.audiostream.com/content/qa-jo...fect-sound

This maybe "disturbing" when we think that computers have often control on our life, but keep cool, audio is really a very special matter

Cheers

[Antoine]

Yeah already shared those the 2nd of September in this topic.