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    The Computer Audiophile

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

    At the Munich High End show this year, I talked to Merging Technologies' Dominique Brulhart about network audio, AES67, Ravenna, and many other items. Needless to say, I learned quite a bit and was really impressed by what is happening in this area of HiFi. After our conversation I asked Dominique if he would be willing to help educate the CA Community on all of this stuff. Dom was 100% on-board and agreed that we didn't even have to discuss Merging Technologies products, as long as we could educate the community. 

     

    Thus, last week I (virtually) sat down with Dominique via Skype and we talked about all things network audio. I couldn't resist asking some questions about the new Merging Technologies ZMan module and a few other items that I thought were too cool to pass up. 

     

     

    Here is the recording of our conversation.

     

    Links:

    AES67

    Ravenna

    Merging Technologies
     

     

     

     




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    6 hours ago, The Computer Audiophile said:

    Keep in mind that standard AES67 devices likely won't cover the sample rates people want. That's where Ravenna devices like the NADAC and ZMan come into play. 

    Good point - currently Dante is 'limited' to 192k PCM and DSD DoP.  Ravenna has that beat.

    But, at least so far Audinate is an open platform, and well now it looks like the AMan will offer this as well.  But what's the cost?  A Dante Brooklyn II card must cost around $120-$150.  It has quality clocks built in.  The issue with Dante is the SDK is very expensive.

     

    I look at how XMOS came to dominate the USB market - providing high SR's, native DSD, etc...with an open platform.  Not quite sure what they charge for the SDK - it may well be free with an order for enough XU208 chips. Once IEEE releases the 'Device Discovery, Enumeration, Connection Management and Control Protocol' to include level 3 (that is GB LAN switch capability) 1733 - it's game on.

     

    Then AVB will be on a level playing field to AES67.  Right now you can buy a fully functioning AoIP XMOS xCore-200 for $299.  This is a AoIP AVB DDC.  Ethernet to SPDIF in/out.  And USB input to boot.  Multi-channel, ADAT, MIDI - all on one board.  Very surprised someone hasn't wrapped a box around it and provided a power supply to market.

    Quote

    Audio connectivity features

    • Up to 32 channel processing
    • 8-channel analog input and output
    • S/PDIF optical/coaxial optical input and output
    • ADAT input and output
    • MIDI input and output

    USB features

    • High-Speed USB device
    • Optional Full-Speed fall-back
    • USB Audio Class 2.0 device; Optional Audio Class 1.0 fall-back
    • Self- or bus-powered
    • Bit perfect USB audio transfer
      • Asynchronous Isochronous to/from USB host
      • PCM 384kHz at 16, 24 or 32bits
      • Local crystal low-jitter audio clocking
    • Multiple OS USB support
      • Windows, Mac OSX, Android

    Networked audio features

    • 10/100/1000Mbit Ethernet connectivity
      • Simultaneous talker & listener
    • AVB standards compliant
      • Time synchronization: 802.1AS
      • Traffic shaping: 802.1Qav
      • Bandwidth reservation: 802.1Qat
      • Media transport: IEEE 1722
      • Discovery and management: 1722.1
    • Bit perfect network audio transfer
      • PLL recovery of AVB clock

     

    xk-audio-216-mc-ab-960.jpg

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    6 hours ago, The Computer Audiophile said:

     

    Not quite sure I follow you. Ravenna is far better than standard AES67. 

    AES67 is a basic interoperability protocol - not an audio std.  Both DANTE and Ravenna provide higher SR's then the 96K AES67 std.

     

    What AES67 does is allow these devices to communicate on the same LAN.  Like for instance in a studio.  So theortically a Dante and Ravenna box can coexit - with compatible Ethernet addressing and clocking I assume. The AES67 protocol allows communication through level 3 GB LAN swtiches.  The one hang up with AVB  currently - needs special switching.

     

    Quote

    It is a layer 3 protocol suite based on existing standards and is designed to allow interoperability between various IP-based audio networking systems such as RAVENNA, Livewire, Q-LAN and Dante. It also provides interoperability with layer 2 technologies, like Audio Video Bridging (AVB)

    https://en.wikipedia.org/wiki/AES67

     

    Quote

    The AES67 standard offers high-performance streaming via audio over IP (AoIP) networks across a wide range of platforms and products, with a focus on “comprehensive interoperability recommendations” in synchronisation, media clock identification, network transport, encoding and streaming, session description and connection management.

    http://www.psneurope.com/aes-standards-committee-ebu-test-aes67-plugfest/

     

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    @Superdad

    Thanks Alex,

    this makes sense now.

    Do Uptone Audio have plans to come up with a Ravenna device?

     

    Matt

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    45 minutes ago, rb2013 said:

    AES67 is a basic interoperability protocol - not an audio std.  Both DANTE and Ravenna provide higher SR's then the 96K AES67 std.

     

    What AES67 does is allow these devices to communicate on the same LAN.  Like for instance in a studio.  So theortically a Dante and Ravenna box can coexit - with compatible Ethernet addressing and clocking I assume. The AES67 protocol allows communication through level 3 GB LAN swtiches.  The one hang up with AVB  currently - needs special switching.

     

    https://en.wikipedia.org/wiki/AES67

     

    http://www.psneurope.com/aes-standards-committee-ebu-test-aes67-plugfest/

     

    Did you listen to my interview in this article? We covered all of this. 

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    53 minutes ago, rb2013 said:

    Then AVB will be on a level playing field to AES67.  Right now you can buy a fully functioning AoIP XMOS xCore-200 for $299.  This is a AoIP AVB DDC.  Ethernet to SPDIF in/out.  And USB input to boot.  Multi-channel, ADAT, MIDI - all on one board.  Very surprised someone hasn't wrapped a box around it and provided a power supply to market.

     

    Because:

    a) Incorporation of XMOS reference design boards in commercial products is not permitted;

    b) XMOS reference design boards suck for quality audio.  (We have worked with several over the years; Trust me, I am not alone in this opinion.)

    9_9

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    56 minutes ago, rb2013 said:

    Then AVB will be on a level playing field to AES67.  Right now you can buy a fully functioning AoIP XMOS xCore-200 for $299.  This is a AoIP AVB DDC.  Ethernet to SPDIF in/out.  And USB input to boot.  Multi-channel, ADAT, MIDI - all on one board.  Very surprised someone hasn't wrapped a box around it and provided a power supply to market.

    Not playing in the same league but, in principle, here's an AVB DAC ready to go:  https://www.minidsp.com/products/network-audio/n-dac8

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    1 hour ago, Superdad said:

     

     

    Matthias:

    Sorry, but you are completely missing the point of the concept, which is to skip the USB>I2S interface.

    The Zman module is an OEM piece to allow DAC manufacturers to incorporate an Ethernet>I2S interface inside their DACs, while the VSC (virtual sound card) software allows for skipping the DLNA/UPnP server/renderer model or other network endpoint models (NAA, RAAT, LMS, etc.).

    There are two primary benefits for home audio:

    1) Ability to use whatever player s/w you wish (the VSC s/w makes your computer "see" the DAC on the network just as if it was a directly-connected "soundcard" like you have with a USB DAC).

     

    2) The Ethernet>I2S (or DSD) module is a relatively low-power low-noise device, and unlike the small, popular, Linux-based streamers/renderers, it does not need a full OS or updates. (This is an advantage for DAC makers who don't want to be in the computer software development and support business.)

     

    So while yes, technically a firm could design a baseboard for the Zman module which generated legacy digital outputs--S/PDIF, I2S over LVDS/HDMI, or even USB (though that would actually be hardest since it would be a host)--such would really miss the point.

     

    There are still (publicly unanswered) technical questions about what Merging is offering with Zman--both regards the VSC s/w, and more importantly regards master clocking--but let's leave that aside for now.

     

    --Alex C.

    Hi Alex - I see a big opportunity for Ethernet to any interface. Tons of DACs only have USB or AES etc... Breathing network life into a $20,000 Berkeley can be a nice thing. 

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    1 hour ago, Superdad said:

    2) The Ethernet>I2S (or DSD) module is a relatively low-power low-noise device, and unlike the small, popular, Linux-based streamers/renderers, it does not need a full OS or updates. (This is an advantage for DAC makers who don't want to be in the computer software development and support business.)

    Actually the Zynq chip has an integrated ARM & FPGA... I've been working with this device also, and agree that its ideal as Ethernet interface. The chip runs Linux and communicates with the FPGA by on die AXI channels. On thing that's trivial is to use the ARMHF build of @Miska's NAA (networkaudiod). All that's needed is an ALSA driver. Same, presumably for RAAT/Roon. I've dabbled in that and it works but has been flakey... no time spent debugging. In any case possible. So basically you have hardware which can run different network protocols.. Now it might be possible to run an IP stack directly in the FPGA but I'm not terribly sure why that would be needed ... but it does run Linux ;)

     

    I don't see any real benefit of Ravenna as a protocol except for software that transmits Ravenna. I think DSD is an "add on". Its way more complicated than RAAT or presumably NAA protocol (if Miska would ever care to open this up we could judge that :) I'm assuming that its a lightweight network transport for ALSA hmm maybe similar to network Jack? In any case my approach is to create an ALSA driver for the AXI DSD interface ... which I'm slowly trying to figure out ... painful for me because all the samples that aren't USB are for PCM only :( 

     

    In any case from a high level I like the ZMan approach ;)

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    5 minutes ago, The Computer Audiophile said:

    Hi Alex - I see a big opportunity for Ethernet to any interface. Tons of DACs only have USB or AES etc... Breathing network life into a $20,000 Berkeley can be a nice thing. 

     

    I am only mostly interesting in advancing SQ.  Ethernet>I2S(DSD) if clocked right is a good way to go, though it too may have performance limitations.

     

    If you want to go Ethernet>USB >USB>I2S then you involve a host(computer) all over again (unless you use ICRON's USB>Ethernet>USB system).

     

    Sure, I can see a Zman (or Coveloz Bach Module) being used to produce a DDC that outputs S/PDIF, AES/EBU, and I2S/DSD over LVDS/HDMI.  I just have a hard time getting excited about do so.

     

    Maybe you can convince Berkeley to produce an "Alpha Ethernet" box to "rescue" their S/PDIF-only DACs. x-D

     

    All kidding aside:

    Anyone who has read what I have written over the years about prospects, promise, and peril of Ethernet audio implementations knows that while I might welcome (and someday embrace) our new overlords, I think  we need to be clear-eyed about what these solutions are and are not.  And given that they all come from the broadcast/event/AV production world, they too come with their own baggage and limitations.  What is being offered now is not strictly a purist audiophile solution.  

    Really the primary compelling element--and as I have said many times, the prerequisite to widespread adoption--will be the availability of multi-platform VSC s/w.  Merging will have a leg up--and possibly a semi-monopoly in the space--by virtue of their being the only ones to offer high-rate supporting VSC s/w on Windows, macOS, and Linux (I assume/hope).

    Would really prefer that such be an included part of the Microsoft's/Apple's OS releases, but who are we kidding--Windows only just recently began to include UAC2 support!

     

    So lot of promise and possibility, but we need to wait and see what products emerge. The first affordable DAC's with Merging Zman modules will undoubtedly attract attention.  But it is just one interface, and it still has to be done right if we expect it to be an advancement.

     

    Just my $0.02  :D

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    2 minutes ago, Superdad said:

    I am only mostly interesting in advancing SQ.  Ethernet>I2S(DSD) if clocked right is a good way to go, though it too may have performance limitations.

     

    I'm looking at 16 channels of DSD1024 -- that enough performance ? :) Clocking right is very very very important :) 

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    9 minutes ago, jabbr said:

    Actually the Zynq chip has an integrated ARM & FPGA... I've been working with this device also, and agree that its ideal as Ethernet interface. The chip runs Linux and communicates with the FPGA by on die AXI channels. On thing that's trivial is to use the ARMHF build of @Miska's NAA (networkaudiod). All that's needed is an ALSA driver. Same, presumably for RAAT/Roon......So basically you have hardware which can run different network protocols.

     

    So then the question--for the Zman module anyway--becomes one of "openness" as to if Merging would allow for other s/w to be loaded onto their module.  Of course there are at least a dozen other SoM (system on module) boards with ARM/FPGA combos (John has been playing with one from Terrasic for over a year, and you have one with the Zynq chip), so nobody is locked into Ravenna as the protocol.

     

    However, NAA, Roon RAAT, etc. are closed in their own ways (even if they might prove to sound better--for unknown reasons--than the Ravenna/AES67 stack and VSC).  As stated before, the interest in Zman from DAC manufacturers will be primarily due to its turnkey implementation--the majority of who's appeal comes from their VSC s/w.

     

    So if you @jabbr write drivers or interface to allow VSC-style use of other SoMs for hi-res audio... Well then we need to talk.  B|

     

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    21 minutes ago, Superdad said:

     

    So then the question--for the Zman module anyway--becomes one of "openness" as to if Merging would allow for other s/w to be loaded onto their module.  Of course there are at least a dozen other SoM (system on module) boards with ARM/FPGA combos (John has been playing with one from Terrasic for over a year, and you have one with the Zynq chip), so nobody is locked into Ravenna as the protocol.

     

    However, NAA, Roon RAAT, etc. are closed in their own ways (even if they might prove to sound better--for unknown reasons--than the Ravenna/AES67 stack and VSC).  As stated before, the interest in Zman from DAC manufacturers will be primarily due to its turnkey implementation--the majority of who's appeal comes from their VSC s/w.

     

    So if you @jabbr write drivers or interface to allow VSC-style use of other SoMs for hi-res audio... Well then we need to talk.  B|

     

     

    VSC = Virtual Sound Card is a remoting interface that installs a local driver e.g. ASIO/WASAPI etc and remotes the Ravenna protocol over the Ethernet. @Miska has developed the NAA protocol as a remoting layer for ALSA. There is also netJack1 and netJack2. netJack1 has Linux, OSX and Windows drivers that probably could be used. So this is doable. Its all usermode programming o.O

     

    If another SoC runs Linux (armhf) then the VSC module run on the client, and talk to a module on the SoC.

    If you wanted to use an FPGA which doesn't run Linux this might require substantially more work ;) I know that Terrasic is Altera but that doesn't tell me which chip he is targeting. If you are worried about Linux "bloat" the dev env allows it to be stripped down to essentially -- you need to compile the kernel custom in any case.

     

    If you mean talking to Merging VSC which uses the Ravenna protocol, then you'd need a Ravenna implementation which runs on Linux -- I'm not interested in implementing that for the heck of it, and I have no reason to believe that I could do it cheaper than the folks who are heavy into Ravenna -- there's a whole bunch of work needed that I don't think is needed for home audio -- now if a Linux Ravenna implementation were made available (source code), that would be a different issue.

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    Sorry for the semi off-topic posts folks.  @jabbr and I will now take this to PMs.  :)

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    2 hours ago, The Computer Audiophile said:

    Did you listen to my interview in this article? We covered all of this. 

    Yes I did - and you did the interview - yet seem to to have a deep lack of understanding of AES67 judging from your posts.  I see why you are 1 yr late to the game.  And you call this 'Computer Audiophile' - shame on you 

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    1 hour ago, Superdad said:

     

    I am only mostly interesting in advancing SQ.

    Really? or the Uptone bottomline?

     

    What is the point of AOIP if USB/Ethernet already smokes it in SQ?  And is cheaper.  Way cheaper! 

    With the ICRON/Startech/LanRover GB LAN extenders - level 3 Ethernet capable. 

     

    Just another CA tail chase.

     

    I see why I never posted on CA...just futile.

     

    Done here.

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    Just now, esldude said:

    Boo!    HISS!    bad play mate.

     

    You added nothing to the discussion and did it in a rude way totally uncalled for here.

     

    If you are a year ahead of us then teach us what you know. 

     

    PS  before time runs out to edit, how about you just remove this post and put something else in its place??

    Boo Hiss...Really?  'You added nothing to the discussion'...what have you added?  Jack.

    I've tried...but you seemed to not to bother reading what I've posted.

     

    Yet feel you can snipe me.  Mate.

     

    Done with CA for good.  You'll have a great CJ with the sponor's product feast.

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    3 minutes ago, rb2013 said:

    Boo Hiss...Really?  'You added nothing to the discussion'...what have you added?  Jack.

    I've tried...but you seemed to not to bother reading what I've posted.

     

    Yet feel you can snipe me.  Mate.

     

    Done with CA for good.  You'll have a great CJ with the sponor's product feast.

    I wasn't sniping.  I have read what you posted.  Some of it was interesting.  I have posted little as I had nothing to add.  Sometimes people embarrass themselves unnecessarily.  I was just being friendly and hoping you would back up a step, let yourself cool down, and continue to contribute here.

     

    The adding nothing to the discussion comment was only about the one post. 

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    9 minutes ago, rb2013 said:

    Done with CA for good.

    Who was that masked man?

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    2 minutes ago, lmitche said:

    This guy.

     

    No.  The masked man was the Lone Ranger, not the Icron Ranger.

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    22 minutes ago, rickca said:

    Who was that masked man?

    The guy who launched the XU208/Singxer F-1/SU-1 thread over a yr ago on HF.  Then the AOIP discussing all this on HF over a yr ago.  Not to mention discovering the Russian '75 HG tubes - 1 million views total. Only to be banned after some troll (like my 'Mate') crashed a very productive thread on my newest discovery - the USB/Ethernet hybrid chain. Well during all that I avoided the Uptone and other sponsor fanboyism here.

     

    But I thought that maybe now was the time here.  I see not.  Now the latest 'Ravenna' fanboyism for a ridiculously overpriced ($10,500 SMPS?!) piece of audio gear.

     

    Before this all gets deleted.  I'm no suck-up - I call them as I see them.  Sorry fanboys of CA - not your b**ch.

     

    30yrs plus of intense high audio experience - listen to what I say or ignore it -your call.  I know what sounds goods and what doesn't.  

     

    So now let the usual (I still remember what you did to poor RE Shaman on the 'Curated' RuR thread- you guys are brutal here). So flame away fanboys!

     

     

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    23 minutes ago, lmitche said:

    Yeah 93,000+ views in 6 months at a site with very few viewers.  I think my thread now surpasses all the other USAM threads combined.  And the feedback on the USB/Ethernet chain has been quite good.

     

    Lot's more to come - I recently made some pretty amazing discoveries.

     

    But you can't have them. LOL!  Got to have a sense of humor folks!  I guess I'll be back in a yr to say 'I told you so'

     

    You a'll be well.

     

    Cheers!

     

    download.jpg

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    Now we'll never know if his highly precise subjective ratings reach 400 or not.  The last incomplete entry was merely a 370. 

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    2 minutes ago, esldude said:

    Now we'll never know if his highly precise subjective ratings reach 400 or not.  The last incomplete entry was merely a 370. 

    You're out of date.  He's already rated something at 500+.

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