Network Dropouts

[NWTStuff]

(21-07-2014 20:07)magister Wrote:  

(21-07-2014 19:42)Mike48 Wrote:  To me, that points to under-engineering of the stream receivers and/or DACs involved.

It seems like it should be a simple thing. But consider this example. PS Audio is coming out with an updated version of their Bridge. In a discussion on the PSA forum, a couple of people said (to paraphrase), "What's the big deal? It's only a network streamer. Why can't you make it do double rate DSD?" Paul McGowan, the CEO of PSA who is very honest in his discussions on the forum, said that nothing in streaming is easy and that making the new Bridge play gapless reliably even at single-rate DSD has been a difficult engineering challenge. Maybe it's not so simple -- yet it works perfectly for some people, as Simon said. Ah, life on the cutting edge of audio.

Yes agree that Paul McGowan is honest as they clearly under engineered the Bridge Version 1. It was the worst Ethernet Bridge that I have tested. One would have to wait 10-15 secs for 24/96 to play (on wired network). There was also a rather nasty white noise in track transition with WAV files.

The dealer that I know bagged up the Bridge and sold units to his clients with i2s and USB Interface only. We look forward to testing the V2 as they have hopefully learned by the V1 experience.

The DirectStream DAC sound is extraordinary by the way. I also liked the Nuwave for look and sound.

[NWTStuff]

(21-07-2014 20:29)simoncn Wrote:  I think a lot depends on what streamer you have. Mine is a Linn DS. It would be interesting to hear about people's experiences with their streamers.

I've been listening to

Synology NAS214play + Minimserver + Atoll ST200 all morning without a single dropout playing 24/96 AIFF files.

Sounds great too. ATOLL have implemented a very nice bridge indeed. That leaves the question how did they end up with USB Audio Class 1.1 on it ? - Not a question for this thread me thinks

[magister]

(06-08-2014 13:13)NWTStuff Wrote:  It was the worst Ethernet Bridge that I have tested. One would have to wait 10-15 secs for 24/96 to play (on wired network). There was also a rather nasty white noise in track transition with WAV files.

The DirectStream DAC sound is extraordinary by the way.

My experience with the Bridge has been better. I get virtually no delay with 16/44, 4-5 seconds (sometimes less) with 24/96, and 6-8 with 24/176 or 24/192. Given the large size of the files involved at 176 and up, it seems reasonable to expect a little delay for the first file in a playlist, or with any file when using a device that does not support gapless playback. The transition noises have been addressed through firmware upgrades (see PSA forum for more on this); I was fortunate never to experience them, although others certainly have. (Another audio mystery . . . )

I certainly agree about the DirectStream: mine was superb-sounding within a few hours, and just keeps getting better. It may well be the best-sounding component I've ever owned. (I have some good stuff but can't afford megabuck pieces.)

[magister]

(06-08-2014 13:37)NWTStuff Wrote:  I've been listening to
Synology NAS214play + Minimserver + Atoll ST200 all morning without a single dropout playing 24/96 AIFF files.

Is Atoll equipment available in the US? I did a little searching and could locate only European dealers. If the PSA Bridge II does not work out, I'll be looking for a new streamer.

I have wondered if dropouts may be related to network speed issues. All my equipment except an old laptop and the Bridge is gigabit ethernet. I looked for a way to tell my Airport Extreme to limit one port (the one feeding the Bridge) to 100Mbs but that doesn't seem possible. My idea was to prevent any buffer overruns, if the Bridge could not keep up with with what's coming at it from the NAS--although most of the time it can. Has anyone else here looked at problem from this perspective?

[simoncn]

(06-08-2014 19:40)magister Wrote:  I have wondered if dropouts may be related to network speed issues. All my equipment except an old laptop and the Bridge is gigabit ethernet. I looked for a way to tell my Airport Extreme to limit one port (the one feeding the Bridge) to 100Mbs but that doesn't seem possible. My idea was to prevent any buffer overruns, if the Bridge could not keep up with with what's coming at it from the NAS--although most of the time it can. Has anyone else here looked at problem from this perspective?

A long time ago, in a land far away, someone invented TCP flow control. This enables the data consumer to telll the data producer when to send data and when not to send data. If the Bridge isn't able to receive more data from the NAS, it should use TCP flow control to make sure the NAS stops sending data until the Bridge is ready to receive it.

[magister]

(06-08-2014 20:23)simoncn Wrote:  A long time ago, in a land far away, someone invented TCP flow control. This enables the data consumer to telll the data producer when to send data and when not to send data. If the Bridge isn't able to receive more data from the NAS, it should use TCP flow control to make sure the NAS stops sending data until the Bridge is ready to receive it.

Thanks, Simon. I expect that the Bridge is using TCP flow control since most of the time it doesn't experience dropouts. So the occasional blips are probably due to something else.

[NWTStuff]

(06-08-2014 20:23)simoncn Wrote:  A long time ago, in a land far away, someone invented TCP flow control. This enables the data consumer to telll the data producer when to send data and when not to send data. If the Bridge isn't able to receive more data from the NAS, it should use TCP flow control to make sure the NAS stops sending data until the Bridge is ready to receive it.

Totally agree. Twin Channel Audio is not a challenging task. use common sense and the tools available, get the comms control right, and you're away. Firmly believe that simplicity in the parameters of the the standard protocols is the way to go.

Thinking aloud I'm hoping that Minim server has been designed properly:-

Idea >> Investigate >> Study >> Reflect >> Design >> Build >> Test >> Rethink >> Rework >> Issue

Comms is the key. And the bad news is it's a kind of a software and logic thing.

A good comms programmer is worth his weight in Gold.

[NWTStuff]

(06-08-2014 19:40)magister Wrote:  Is Atoll equipment available in the US? I did a little searching and could locate only European dealers. If the PSA Bridge II does not work out, I'll be looking for a new streamer.

I have wondered if dropouts may be related to network speed issues. All my equipment except an old laptop and the Bridge is gigabit ethernet. I looked for a way to tell my Airport Extreme to limit one port (the one feeding the Bridge) to 100Mbs but that doesn't seem possible. My idea was to prevent any buffer overruns, if the Bridge could not keep up with with what's coming at it from the NAS--although most of the time it can. Has anyone else here looked at problem from this perspective?

Magister,

Never had a problem streaming from the ATOLL but again I don't own it so I really wouldn't say it's a strong recommendation. Let's say a gut feel well worth having a look at !

In your house forget the word GB ethernet. it just gives the infrastructure for GB comms. Let's say it passes the buck to the equipment comms interfaces so you will be clear where your bottlenecks will lie.

Good comms design will not let any buffer overruns occur. The good old send an receive scenario is more valid than ever.

I'll check the distribution situation in US for ATOLL, it's nice kit.

Kevin

[NWTStuff]

(06-08-2014 19:31)magister Wrote:  My experience with the Bridge has been better. I get virtually no delay with 16/44, 4-5 seconds (sometimes less) with 24/96, and 6-8 with 24/176 or 24/192. Given the large size of the files involved at 176 and up, it seems reasonable to expect a little delay for the first file in a playlist, or with any file when using a device that does not support gapless playback. The transition noises have been addressed through firmware upgrades (see PSA forum for more on this); I was fortunate never to experience them, although others certainly have. (Another audio mystery . . . )

I certainly agree about the DirectStream: mine was superb-sounding within a few hours, and just keeps getting better. It may well be the best-sounding component I've ever owned. (I have some good stuff but can't afford megabuck pieces.)

Magister

Totally sure that we agree that Sound is the Objective. To wait 5 seconds for the best sound you can buy is squirrel shit.

However I must state that charging approx $600 for a Network Bridge that can be outstripped by an Ethenet Bridge on a Raspberry Pi that cost £25 is rather heading towards the rip off area.

5 secs at 24/96 is like a life time IMHO. This equates to 0.58 MB/s which is generally know in the UK as Sweet FA in the theoretical GB/s world

Enjoy your DirectStream. IMHO you are very fortunate to own one.

PS Audio missed a huge trick by launching their own/re-badged bridge (well a commercial decision in any case). There are plenty out there that do a better job.

Kevin

[simoncn]

(07-08-2014 00:05)NWTStuff Wrote:  Totally agree. Twin Channel Audio is not a challenging task. use common sense and the tools available, get the comms control right, and you're away. Firmly believe that simplicity in the parameters of the the standard protocols is the way to go.

Thinking aloud I'm hoping that Minim server has been designed properly:-

Idea >> Investigate >> Study >> Reflect >> Design >> Build >> Test >> Rethink >> Rework >> Issue

Comms is the key. And the bad news is it's a kind of a software and logic thing.

A good comms programmer is worth his weight in Gold.

You won't be surprised that I have a background in comms software (and servers).

Your lifecycle of MinimServer is exactly correct but it is missing a very important part:

.... >> Issue >> Get user feedback >> Reflect >> Rethink >> Rework >> Reissue >> ....