17-May-2019, 23:04
@daniel.avasilichioaei
Interesting comparison. Like I said before, I know nothing about networking so asking me why there's a difference in the amount of traffic between AIR and RAAT isn't likely to be all that productive but I will make two comments that may mean more to you than they mean to me. Since you've got the software to make those measurements you made I'm betting that you know a lot more about networking than I do because I had no idea at all about how to go about making that kind of measurement in the first place.
Roon have a webpage where Roon talk about RAAT and what their design goals for it were (https://kb.roonlabs.com/RAAT).
Buried in the design goals section is the following statement:
"Audio devices must own the audio clock. Many other protocols get this wrong, including AirPlay. It's not possible for two clocks to agree perfectly. Letting the DAC control the pace of streaming removes the need for a clock-drift-compensation mechanism that is bound to increase cost, decrease sound quality, or both."
If the Devialet is controlling the pace of streaming with RAAT and ROON is controlling it with AIR, then perhaps part of the difference in traffic is due to differing amounts of communication between Roon and the Devialet with the 2 protocols.
As for the increased traffic from Devialet to Roon, another factor may be the amount of data the Devialet communicates. Using RAAT, the signal path display in Roon will give you information about tone control and SAM settings if you're using those adjustments. I don't know whether that information is sent to Roon if you're using AIR but I suspect not. I know the Devialet AIR app never used to display such info back in the days when I was using it before I started using Roon so I suspect that the AIR protocol wasn't designed to convey that information and as far as I know the AIR protocol didn't change when Roon incorporated it into their software. My guess is that with RAAT the Devialet sends more info back to Roon about how it's processing the signal than it does with AIR.
So that's 2 areas with RAAT where the Devialet may be sending more data to Roon than it does with AIR. I have no idea how much data may be involved with that.
When it comes to Roon sending almost twice as much data to the Devialet with RAAT, could that be due to error correction and resent packets due to issues with this gigabit connection problem? People aren't getting that problem with AIR and while those with the problem are noticing problems when dropouts occur, that doesn't tell us anything about how much traffic is being resent due to error correction when the error correction process is working and dropouts are being avoided because of it. It would be interesting to repeat these measurements when the gigabit problem is solved and see whether your results for RAAT change with the fix.
Those are my uneducated guesses.
As to why use RAAT rather than Roon AIR, in my case I hear a sound quality difference and I prefer RAAT. It sounds more natural to me. Roon AIR doesn't sound bad to me, it sounds good and I was quite happy using it before we got the Roon Ready update. I'd still be using it if we hadn't got the update and using it happily at that. We got the update and I did a comparison and preferred RAAT, and I wasn't getting any problems streaming the content I have on my drive at its native resolution so I've stuck with RAAT. I've swapped back to AIR a couple of times since February to see if my feelings have changed and I still prefer RAAT. There's been a poll on the topic of RAAT vs AIR and the last count I saw on the poll had more people preferring RAAT but a reasonable showing for AIR. In my view the options one had to select from were very badly worded and weren't clear in at least one case but even making allowances for that RAAT still seemed to come out slightly ahead on the preferences.
Interesting comparison. Like I said before, I know nothing about networking so asking me why there's a difference in the amount of traffic between AIR and RAAT isn't likely to be all that productive but I will make two comments that may mean more to you than they mean to me. Since you've got the software to make those measurements you made I'm betting that you know a lot more about networking than I do because I had no idea at all about how to go about making that kind of measurement in the first place.
Roon have a webpage where Roon talk about RAAT and what their design goals for it were (https://kb.roonlabs.com/RAAT).
Buried in the design goals section is the following statement:
"Audio devices must own the audio clock. Many other protocols get this wrong, including AirPlay. It's not possible for two clocks to agree perfectly. Letting the DAC control the pace of streaming removes the need for a clock-drift-compensation mechanism that is bound to increase cost, decrease sound quality, or both."
If the Devialet is controlling the pace of streaming with RAAT and ROON is controlling it with AIR, then perhaps part of the difference in traffic is due to differing amounts of communication between Roon and the Devialet with the 2 protocols.
As for the increased traffic from Devialet to Roon, another factor may be the amount of data the Devialet communicates. Using RAAT, the signal path display in Roon will give you information about tone control and SAM settings if you're using those adjustments. I don't know whether that information is sent to Roon if you're using AIR but I suspect not. I know the Devialet AIR app never used to display such info back in the days when I was using it before I started using Roon so I suspect that the AIR protocol wasn't designed to convey that information and as far as I know the AIR protocol didn't change when Roon incorporated it into their software. My guess is that with RAAT the Devialet sends more info back to Roon about how it's processing the signal than it does with AIR.
So that's 2 areas with RAAT where the Devialet may be sending more data to Roon than it does with AIR. I have no idea how much data may be involved with that.
When it comes to Roon sending almost twice as much data to the Devialet with RAAT, could that be due to error correction and resent packets due to issues with this gigabit connection problem? People aren't getting that problem with AIR and while those with the problem are noticing problems when dropouts occur, that doesn't tell us anything about how much traffic is being resent due to error correction when the error correction process is working and dropouts are being avoided because of it. It would be interesting to repeat these measurements when the gigabit problem is solved and see whether your results for RAAT change with the fix.
Those are my uneducated guesses.
As to why use RAAT rather than Roon AIR, in my case I hear a sound quality difference and I prefer RAAT. It sounds more natural to me. Roon AIR doesn't sound bad to me, it sounds good and I was quite happy using it before we got the Roon Ready update. I'd still be using it if we hadn't got the update and using it happily at that. We got the update and I did a comparison and preferred RAAT, and I wasn't getting any problems streaming the content I have on my drive at its native resolution so I've stuck with RAAT. I've swapped back to AIR a couple of times since February to see if my feelings have changed and I still prefer RAAT. There's been a poll on the topic of RAAT vs AIR and the last count I saw on the poll had more people preferring RAAT but a reasonable showing for AIR. In my view the options one had to select from were very badly worded and weren't clear in at least one case but even making allowances for that RAAT still seemed to come out slightly ahead on the preferences.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.
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