Article: A Conversation About Network Audio, AES67, Ravenna, and Merging Technologies

[dbrulhart]

8 hours ago, input username here said:

Thank you Chis, this was, as always, a great service to the CA community.  I am pretty sure I get it, but I have a few questions, if you don't mind.

 

1. Mr. Brulhart mentioned that "many" other manufacturers had already implemented systems with similar capabilities to Ravenna.  I assume he was talking about other pro applications, like Dante, but doesn't, say, Sonos do exactly the same thing too?  Of course the BIG difference being that Sonos's protocol will only mesh Sonos products, whereas Ravenna will (or at least promises) to link devices from many different companies.  Are there any other advantages to Ravenna (I know that Sonos also currently does not run high sample rates)?

 

2. Similar to monteverdi's observation, I wish that sound quality would have been discussed more.  It seems like LAN-based devices should sound better, but do they in practice?  Would a (old school) CD transport sound better if it sent its data to the DAC over (Ravenna) LAN, rather than AES or S/PDIF or even I2S?

 

3. And finally,while the allure of multi-channel audio never caught on for me, multi-channel video remains interesting.  Would you be able to process, say, Dolby Atmos, DTS:X or Auro-3D on the Zman module (or on whatever server is sending data to the Zman) and remove the need to buy an expensive (and, soon-to-be obsolete) hardware surround processor?  That would be something cool....

 

Thanks again!

 

Dear "input username here",

 

1) On the pro side there are dozens of manufacturers who implemented Ravenna in both hardware and software. But I was talking about the consumer/audiophile side here. We are currently deploying our Linux Ravenna driver on various manufacturers products. We have shown working Aurender, Melco and Roon-ROCK systems in Munich in May, but there are a good number of others currently integrating our driver. Technically, we can add to the picture all applications running on Windows and MacOS as their manufacturers benefit from the Ravenna support through our Windows and MacOS drivers as well, like Roon, JRiver, Audirvana, etc, etc. This is for the "software" side. On the hardware side, the only consumer products supporting Ravenna today are NADAC and NADAC PLAYER, but the soon availability of the ZMan board will add many to the game. There are here also a good number of companies currently working on integrating ZMan in their DACs, speakers or other devices.

 

2) Stricto-senso, the "quality" of the bits transfered by Ethernet, USB, Firewire, Thunderbolt or even AES or SPDIF is the exact same. Every bits reach the destination intact and in the proper sequence. If it weren't the case we wouldn't discuss about sound quality but about glitches, pops, scratches or bangs. So, on the transport aspect, all those technologies are equal (if we put aside latency, number of channels, resolution, which are quantity considerations and not quality considerations). However, the sending and receiving devices can be more or less accomodating to the technology involved by these transmissions, some are synchronous, some are asynchronous, some have more or less jitter, some are more of less precise, etc... and it is then down to the sending and receiving devices to be properly designed to accomodate with these constraints. In theory all those transmission mediums can sound equivalent if the hardware implementing them is properly designed. So in that sense Ethernet can have some advantages, like a better galvanic isolation, specially if using optical cables. Ravenna is a very precise, low jitter and low latency protocol, so meaning that it can have, in theory, advantages in the design of hardware communicating with it. But it's main advantage is definitely its flexibility. Quality is really down to the engineers not to the technology.

 

3) Well, there are many aspects in  surround processors: the format decoding, but generally also processing (as its name suggest), like channel mapping, down-mixing, up-mixing, room correction and more creative effects (like stadium effect, action movie effect, etc...), and this can be quite costly in term of DSP. We plan offering some processing capabilities in ZMan, like room correction (to some level), EQ, up/down mixing, up/down sampling, etc... We are also investigating format decodings, however today any (decent) Bluray player actually properly decodes Atmos, DTS:X and Auro, so no real need to be done externally. So, on a purist approach of sound quality, if we were to use ZMan in this context, I would be more tempted to let the Bluray player decode the format itself, give up on special effects, and keep the DSP for either some room correction or some upsampling. Typically an HDMI audio to Ravenna converter would be the perfect link between Bluray players or video servers to Ravenna enabled DACs. As mentionned in the interview, Ravenna would allow as standard to start with a stereo DAC, then add more DACs later for the surround. Or even allow for hybrid solutions, with a very high-end "traditional" stereo system for the front, and active Ravenna enabled speakers for the rear and center. As Chris said: the limit is the imagination.

 

Best regards,

 

Dominique