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Air & Devialet memory (technical)
#11
(04-May-2015, 13:04)f1eng Wrote: Air version 1 was Mac/iTunes only and once de-bugged worked brilliantly. Apparently too many potential customers were anti iTunes, or Mac or both and it was completely re-written as version 2, which only shares the name not the concept, is universal and has not been satisfactorily de-bugged yet.
Very much not a case of "the customer is always right" IMO!

OTOH sending data down a wireless network is what wifi does and the idea that "common sense says it won't work" is technically ridiculous. Sorry.

No need to apologise! I was actually talking about wired Ethernet so I suppose I was being even more ridiculous.  Blush

Perhaps you're right. It's just that sending data down a network is what they're designed to do, but Devialet in their wisdom have decided to use their own mechanism and in doing so have chosen very small data packets in a time critical situation with a small buffer. To my mind, that just dramatically increases the chances of problems. If there are these alleged timing bugs within core parts of osx and windows causing problems, using larger data packets would surely delay their onset?

I'm just clutching at straws. But what I do know is it doesn't work! Certainly not to a level I'd expect to accompany a £6,000 amp/dac. I might be more understanding if the product had only been released a few weeks ago, but....

For what it's worth I prefer the soundcard approach as I can stream qobuz too - interestingly even at the same time as itunes. Yesterday I was thinking I'd bought quite an experimental album until I realised I'd hit play in qobuz while itunes was playing.

>>> 1st Place Award: Devialet, last decades most disappointing technology purchase.  <<<

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#12
(03-May-2015, 09:15)thumb5 Wrote: I think the post that Phil linked to explains what's causing the frequent network activity when the Devialet is not actually streaming.  The network activity in that case is probably to do with the discovery mechanism used by AIR and/or the iPhone app.

For information about what's happening when it is streaming, you could take a look at this: http://devialetchat.com/showthread.php?tid=276.

As far as the buffer is concerned, I recall someone here (Antoine?) confirmed that the on-board buffer RAM is in the region of 1-2 MB, so nowhere near large enough to store a whole track but should be plenty to cope with timing variations and network delays.  By the way, I wouldn't describe that as "really small" for an embedded system.

That seems a reasonable design decision to me: it's hard to define how much memory you'd need to store a whole track -- how long is the longest possible track?  Could be an hour or more, and at 24/192, for example, storing raw PCM data for one track of that length would need more than 4 GB RAM (which is probably not addressable by the processor). 

Hope that helps,

Ian

Yep, I did look it up but the memory on the AIR WiFi addon card buffer is 32MB(yte), so a bit more than 1-2MB.

http://devialetchat.com/showthread.php?t...80#pid1180
PS Audio P3, Shunyata ΞTRON Alpha Digital and HC/Furutech power cables, Paul Hynes SR7EHD-MR4, DIY Roon Server & Roon Endpoint running AudioLinux Headless, Phasure Lush^2 USB cable, Audioquest Diamond RJ/E ethernet, Uptone Audio etherREGEN, Mutec MC-3+ USB, Shunyata ΞTRON Anaconda Digital XLR AES/EBU, Devialet Expert 250 Pro CI, Nordost Tyr Reference LS cables, Von Schweikert VR-5 SE Anniversary Edition, Anti-Mode Dual Core 2.0, JL Audio Fathom F112. More detail here.

The Netherlands
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#13
(04-May-2015, 16:04)Hifi_swlon Wrote: Perhaps you're right. It's just that sending data down a network is what they're designed to do, but Devialet in their wisdom have decided to use their own mechanism and in doing so have chosen very small data packets in a time critical situation with a small buffer.

I don't understand the distinction you're trying to make.  It is just data being sent across the network, independent of the packet size and whether it comes from Devialet AIR or not.

The packets AIR sends (at least as I saw when streaming 16/44) are about 1000 bytes.  The largest possible packet on a 10/100 wired Ethernet can carry 1500 bytes of payload.  So to call them "very small" seems to me to be just exaggerating for effect.

As Antoine has pointed out to correct my earlier post, the buffer in the Devialet is in fact 32 MB.  That's enough to buffer about 30 seconds of raw PCM 24/192 stereo audio samples, which should be far more than is needed to cope with the typical delays that might be experienced in a reasonably-working home network.

(04-May-2015, 16:04)Hifi_swlon Wrote: To my mind, that just dramatically increases the chances of problems. If there are these alleged timing bugs within core parts of osx and windows causing problems, using larger data packets would surely delay their onset?

As I understand it, the timing bugs that are being discussed are to do with synchronising clocks so that the amplifier and AIR running on the host computer stay in synch over a long period of time.  That problem is largely if not completely independent of the network transport.  In fact you could just as well argue that using larger packets would if anything be a worse approach for transmission of real-time data.

(04-May-2015, 16:04)Hifi_swlon Wrote: I'm just clutching at straws. But what I do know is it doesn't work! Certainly not to a level I'd expect to accompany a £6,000 amp/dac. I might be more understanding if the product had only been released a few weeks ago, but....

The fact that AIR doesn't work well in your system shouldn't be generalised.  AIR does work well enough for a reasonable proportion of users.  No, it is not perfect, and Devialet do need to fix some bugs, but the basic approach to transferring data across the network seems sound to me.
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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#14
(04-May-2015, 18:08)thumb5 Wrote: As I understand it, the timing bugs that are being discussed are to do with synchronising clocks so that the amplifier and AIR running on the host computer stay in synch over a long period of time.  That problem is largely if not completely independent of the network transport.  In fact you could just as well argue that using larger packets would if anything be a worse approach for transmission of real-time data.

I may be wrong, but my reading of the bug description for Windows is within Windows and is independent of any networking issue. Interestingly, the bug I'm aware of in MacOS and that also causes the drops in MacOS Air is independent from the network since it is at the interface between the IOStream and the driver.

Jean-Marie
MacBook Air M2 -> RAAT/Air -> WiFi -> PLC -> Ethernet -> Devialet 220pro with Core Infinity (upgraded from 120) -> AperturA Armonia
France
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#15
(04-May-2015, 18:08)thumb5 Wrote: The fact that AIR doesn't work well in your system shouldn't be generalised.  AIR does work well enough for a reasonable proportion of users.  

Respectfully, I'm not just generalising from my experience, it's also based on the polls here which - assuming they represent a tiny fraction of Devialet users - contradict that view. Anyway, I don't mean to be antagonistic, it's just I find it hard to see why anyone would defend it. If Air worked, there would be quite a few less posts here!

I'm assuming from your stance that it works flawlessly in your setup? Do you use Ethernet or wifi?

>>> 1st Place Award: Devialet, last decades most disappointing technology purchase.  <<<

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#16
(04-May-2015, 19:14)Hifi_swlon Wrote:
(04-May-2015, 18:08)thumb5 Wrote: The fact that AIR doesn't work well in your system shouldn't be generalised.  AIR does work well enough for a reasonable proportion of users.  

Respectfully, I'm not just generalising from my experience, it's also based on the polls here which - assuming they represent a tiny fraction of Devialet users - contradict that view. Anyway, I don't mean to be antagonistic, it's just I find it hard to see why anyone would defend it. If Air worked, there would be quite a few less posts here!

I'm assuming from your stance that it works flawlessly in your setup?  Do you use Ethernet or wifi?

AIR works perfectly in my set-up both for wifi and wired connections and when streaming 24-bit files. I've had no white noise and no drop-outs....ever. This is probably because I've stayed on OSX 10.6.8 to avoid problems that others have reported particularly with Yosemite.

I know it's not ideal but you could try using USB or optical connections between your Mac Mini and Devialet. You won't have any problems with white noise and then once the problems are fixed you can switch back to AIR...
IMac macOS 10.15.3 (no link to Devialet Sad ) / MacBook Pro Retina OS X 10.14.4 / Linn LP12 / Devialet 200 Wilson Benesch Discovery. 
Qobuz Desktop Latest Version / Audirvana 3.2.18 / Audirvana Remote / iTunes 12.9 / AIR 3.0.4 / Wi-Fi / FW 8.1.0 / SAM 50%
Cambridge, UK (Updated 27th February, 2020)
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#17
I might have to, its driving me nuts!
But I was about to wall mount (or put on a stand) and clear out all the remaining hifi gear from the lounge - putting the mini upstairs. Which was a big selling point of the Devialet for me. Oh well, I guess I'll try and maybe delay that plan.

>>> 1st Place Award: Devialet, last decades most disappointing technology purchase.  <<<

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#18
(04-May-2015, 19:14)Hifi_swlon Wrote:
(04-May-2015, 18:08)thumb5 Wrote: The fact that AIR doesn't work well in your system shouldn't be generalised.  AIR does work well enough for a reasonable proportion of users.  

Respectfully, I'm not just generalising from my experience, it's also based on the polls here which - assuming they represent a tiny fraction of Devialet users - contradict that view. Anyway, I don't mean to be antagonistic, it's just I find it hard to see why anyone would defend it. If Air worked, there would be quite a few less posts here!

Point taken, and I'm sorry if I misunderstood you.

Looking at the poll dispassionately, about a third of the people who responded don't get any problems.  Of the remainder it's hard to say how serious are the problems that they experience - could be anything from "it barely works" to "it works almost perfectly".  Because the poll is not a random sample of Devialet users, I'd expect it to over-represent the occurrence of problems because people who do have problems are more likely to be aware of this site, and more motivated to respond to the poll.  (That's not in any way to devalue the poll as a way of gathering some concrete information about the frequency of problems.)  

(04-May-2015, 19:14)Hifi_swlon Wrote: I'm assuming from your stance that it works flawlessly in your setup?  Do you use Ethernet or wifi?

In my system it works nearly flawlessly - I have short drop-outs very rarely, but thankfully nothing on the scale of the white noise discussed elsewhere on the forum.  My computer is wireless to my router, and the Devialet is wired.  Incidentally, in the poll I said I did experience problems.

As I said, AIR is (obviously) not perfect.  But equally I think it's unreasonable to say "it doesn't work" as a blanket, binary judgement.  It's more reasonable to say that it works perfectly well for some people and less well for others.  I have a lot of sympathy if it's not working for you, as I know how frustrating that sort of thing can be, but it's not necessarily an indication that the design is fundamentally broken.  Otherwise, surely it wouldn't work reliably for anyone?
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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#19
(04-May-2015, 20:17)thumb5 Wrote: As I said, AIR is (obviously) not perfect.  But equally I think it's unreasonable to say "it doesn't work" as a blanket, binary judgement.  It's more reasonable to say that it works perfectly well for some people and less well for others.  I have a lot of sympathy if it's not working for you, as I know how frustrating that sort of thing can be, but it's not necessarily an indication that the design is fundamentally broken.  Otherwise, surely it wouldn't work reliably for anyone?

I don't mean to be boring, I guess I'm just a bit old school in terms of the casual use of "works" and "doesn't work". 

I read the above as "doesn't work", you, and I'm sure many others read it as "works". All good.   Wink

(Note to self: must stifle frustrations and find something more useful to spend time on….)

>>> 1st Place Award: Devialet, last decades most disappointing technology purchase.  <<<

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#20
(05-May-2015, 09:39)Hifi_swlon Wrote: I don't mean to be boring, I guess I'm just a bit old school in terms of the casual use of "works" and "doesn't work". 

I read the above as "doesn't work", you, and I'm sure many others read it as "works". All good.   Wink

(Note to self: must stifle frustrations and find something more useful to spend time on….)

Understood.  It's hard to disentangle from one's personal experience; if I was having more drop-outs or other problems with AIR, I'm sure I'd have a different view on the poll results Wink
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
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