Topic: RME Digiface AVB + AVB Tool and Motu AVB devices

Hi,

I have a question:
My plan is to use a Digiface AVB in 96khz/24bit mode and an AVB Tool to connect my BURL B16 via BM2 MADI optical card.

With this configuration in place, would adding a Motu 16A or Ultralite AVB be possible and make those I/O discoverable on the RME Digiface side to let me route their I/Os to and from the Digiface in 96khz/24bit?

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

AVB implementations can differ between vendors, so a group of manufacturers including RME have focused their efforts on an interoperability standard for audio devices on AVB networks called MILAN. Unfortunately, I have not seen any signs that MOTU plans to modify their AVB implementations for full MILAN compliance, whereas the AVB Tool will be one of the first RME devices to be fully MILAN compliant.

On the contrary, while numerous AVB implementations from various vendors (Apple, AVID, d&B, L'Acoustics, Meyer Sound, Neutrik, to name a few) have changed towards MILAN compliance in the past couple of years, the MOTU devices have not seen a firmware update since May 13th, 2019 and in my own tests, they do not implement a number of features that would be necessary to be fully interoperable. They neither support the mandatory stream formats nor the default AVB maximum transit time, they do not implement counters (for stream statistics and error detection), and several other things.

In general, you will most likely succeed in streaming between MOTU and RME devices (choosing a compatible stream format, 8 Ch. AM824), but you may encounter issues (when re-connecting streams or changing the network while streaming) and RME cannot support those types of issues. It is impossible to test our devices continuously against all AVB implementations out there. So I highly recommend using vendors that state publicly that they are MILAN compliant or at least working towards full MILAN compliance.

There may be a number of forum users that use the combination though, and I welcome everyone to chime in and report their experiences in this thread, especially if it works without problems ;-).

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

Thank you for the detailed answer!

So would running 8ch. AM824 mode be fine with both RME Digiface AVB and AVB Tool being part of the same network with some device that runs AM824? This 8 channel stream would be 96khz/24bit?

Or can each of the streams be different in the same network, like 1 stream of 8ch. AM824 stream and the others Milan?

Is there any shortcoming, if AVB Tool is the first "fully milan" device compared to Digiface AVB, and would the Digiface also become fully Milan compatible via a firmware update?

These questions may be obvious, but I've never heard of AVB (nor Dante) a week ago and couriously interested to get into it to plan extend my setup.

4 (edited by Max 2022-03-09 05:26:35)

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

Without knowing details of MOTU's implementation it is hard to answer those questions.

The stream format is not a problem in general, as compatibility can be checked quickly: it either works or doesn't work. RME devices support the stream format that MOTU uses in addition to the newer AAF stream format. This will not be removed anytime soon, even with MILAN certification. And yes, every stream can have a different format (and it can even have its own independent sampling rate).

The issues you'll be facing are more related to the way streams are established in the beginning and how they are monitored. MILAN has a very specific approach to that and it is different from MOTU's approach. I was able, for example, to receive AM824 streams from a MOTU device in a quick test, but MOTU would not receive a stream from the AVB Tool with current firmware (even though it was the same stream format). And as soon as you face issues like that, we can't really help much.

The Digiface AVB has a 'leftover' compatibility mode to provide better support for non-MILAN compliant devices that apparently improves (did a brief test) connections to/from MOTU devices, but that mode applies to all streams (it is a global setting), and then causes MILAN-connections not to function. This mode is not available on the AVB Tool, because it breaks MILAN connectivity and compliance.

The obvious (and probably only) way for manufacturers to be interoperable on AVB networks is to use MILAN (an open subset of the open AVB set of standards). Connecting two MILAN devices will always work no matter what.

For an audio interface like the Digiface AVB, the certification is a bit more complex and this is not currently on our timeline. Think for example about setting the sampling rate over network from an AVB controller while your DAW has requested a specific sampling rate via ASIO/CoreAudio. There are some conflicts of interest where the audio interface has to restrict its configuration options from the network in order not to cause instability in the audio driver architecture of the DAW. But we do test against MILAN devices and make sure that there are no issues that would cause interoperability issues. The Digiface AVB has received numerous firmware and driver updates to extend compatibility in the past year, so generally speaking, it is supported as a MILAN endpoint.

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

Alright, since I really trust and use RME interfaces for years now on Windows machines, I'll take the plunge and order a Digiface AVB and AVB Tool for the madi connectivity and see what to do next then. Just realized how small the digiface really is, so to think that it can handle so many channels with just one ethernet cable is just mindboggling smile

Will probably have more questions then, but opening new topics for each to not drift OT.

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

Great! Keep in mind that you also need an AVB switch, such as the Presonus SW5E, in case you don't have one already.

7 (edited by FireGS 2022-03-28 22:17:58)

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

So this post might come off as slightly tangential, but I think it's worth writing in this thread.

I'm running this combination of devices with mostly successful results.

AMD Ryzen x570 PC > Digiface AVB > MOTU 1248 > MOTU 24AO (4x) via a Netgear Netgear GS724Tv4 switch with EAN License (hey -- 24 ports for AVB vs 5 from MOTU and Presonus for the same price ^_^ )

I did run into some issues:

  • MOTU's AVB devices are limited to 64 channels via USB(2).

  • x570 motherboards do not support Thunderbolt which supports 128 channels, nor support Thunderbolt add-on cards since there's no Thunderbolt header on those motherboards. (Which is why I bought a Digiface AVB to begin with)

  • RME's implementation of USB3 kinda sucks for current-gen AMD motherboards since most (all?) x570 boards are supplied with multiple variants of ASMedia USB chipsets. It's not mentioned anywhere on the RME website, and I had to find out after the fact that the Digiface AVB does not support ASMedia chipsets.

  • I had to buy an additional Fresco USB 3 USB card to make the Digiface AVB work at all without chirps, clicks, dropouts, and tons of CRC errors. (Tried every port, multiple cables -- same thing)

  • I still have dropouts and CRC errors from time to time.

All of that said, I've used the Digiface AVB in DAW mode (TotalMix), and MILAN compatibility on. Set the input and output streams to 16, with 8 channels set as the input formats. After that, all of the MOTU side of configuration happens on the MOTU web app, and it seems to be perfectly fine between the multiple MOTU devices. Most of the issues still lie in the USB3 connection between the PC and the Digiface AVB.

The only remaining issue to solve is the most reliable/beneficial clocking method. I bounce back and forth between using the Digiface AVB as the master clock and the 1248, as well as bounce between using coax worldclock and using the AVB streams as world clock. Would love some input on that.

8 (edited by ramses 2022-03-28 23:23:49)

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

3rd party USB3 chips from ASMedia are known to cause issues. Therefore the RME manual contains information in ch 25.1, that ASMedia USB3 chips are not compatible.

You have two options:
a) to use USB3 ports coming from chipset (AMD or Intel) .. EVERY mainboard has USB3 ports coming from chipset. Use those, consult your mainboards manual.
b) to use an additional PCIe card with e.g. USB3 chips from Fresco Logic (FL1100)

You picked option b) (what I also did) as this gives you the big benefit to fully isolate your recording interface from the rest of the USB infrastructure of your mainboard.

I personally made the experience with my Supermicro Server mainboard that at the beginning the USB3 ports from chipset worked. But then I added more and more USB devices, also USB Bluetooth adapters and then some audio drops startet when using small ASIO buffer sizes.
Such problems were immediately fixed by using a dedicated PCIe card for the recording interface (UFX+) with a supported USB3 chipset.

There can be different reasons why you still might have issues with USB transport errors. USB3 cable length, cable quality, maybe issues with the PCIe slot that you use (maybe shared with other resources). I would consult the manual or ask support which PCIe slot has PCIe lanes coming from the CPU, not from chipset.

BR Ramses
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro22H2, Cub12Pro

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

ramses wrote:

a) to use USB3 ports coming from chipset (AMD or Intel) .. EVERY mainboard has USB3 ports coming from chipset. Use those, consult your mainboards manual.

Specifically about this, x570 boards use ASMedia for both USB chipsets, the one directly tied to the CPU and the "southbridge".

Color me shocked, too.

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

FireGS wrote:

Specifically about this, x570 boards use ASMedia for both USB chipsets, the one directly tied to the CPU and the "southbridge".

Color me shocked, too.

What about boards with three USB controllers? According to USBTreeView, only one of mine is ASMedia. (Haven't examined the actual silicon on the PCB).

Re: RME Digiface AVB + AVB Tool and Motu AVB devices

Yearofthegoat wrote:
FireGS wrote:

Specifically about this, x570 boards use ASMedia for both USB chipsets, the one directly tied to the CPU and the "southbridge".

Color me shocked, too.

What about boards with three USB controllers? According to USBTreeView, only one of mine is ASMedia. (Haven't examined the actual silicon on the PCB).

What does USBTreeview say for the others? Generic?

What motherboard do you have specifically make and model?