1 Topic by gleeman (edited by gleeman 2021-10-01 13:53:05)

  • From: Sardinia
  • Registered: 2007-10-27
  • Posts: 11

Topic: MOTU 24AI / AO compatibility

TLDR; What's the compatibility of MOTU AVB 24AI / AO with RME AVB products? For example a Digiface AVB or a Madiface USB + AVB Tool?

Explanation:
I'm planning to setup a hybrid home-studio for recording small bands live and for video sound post-production.

My main sound card will be RME: driver stability, Totalmix and Digicheck are an indispensable part of my workflow

I would really like to have a MADI or AVB setup since I would prefer not to have long analog cables running from the control room to the tracking room, but it seems to me that AVB will be a more flexible and future-proof solution. I would not go the Dante route if possible.

I need about 24 input channels for tracking (preamps will be located in the tracking room near the artists)
and at least 12 channels of output in the control room (in case I need to setup a 7.4.1).
Let's not talk about other analog channels for the outboard at the moment.

I already have a good amount of analog preamps which I like, so I ruled out buying a couple of 12Mics for the input, instead I would need to buy an AD converter. Unfortunately the m 32 pro AD is a little too expensive at the moment, I'll eventually upgrade once the studio is operating at full capacity.
Same thing for the DA, also I don't need 32 channels and the 1610 pro has not enough channels for a full dolby atmos setup.

It seems to me that there are not much options in the AVB world other than motu 24 converters and presonus stageboxes, but I didn't find anything in the forum about their compatibility with RME products.

  • Max
  • Max
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  • Registered: 2007-05-09
  • Posts: 315

Re: MOTU 24AI / AO compatibility

RME follows MILAN (a subset of AVB) as an interoperability layer. As of today, MOTU devices do not support some of the MILAN requirements, therefore testing their devices against RME is a bit tedious. Last time I tested the Digiface AVB in legacy 1722.1 mode worked with MOTUs AM824 8Ch streams, while there were some issues with the other devices that do not have this mode. But it is been a while and we might take another look into that. You could start out using the AVB Tool with a Digiface AVB as a MADI interface and initially hook up cheaper ADs/DAs to the AVB Tool - that would even work without an AVB switch.

Thanks for explaining your setup and need for 24in / 12out. Just out of curiosity, how do you do (headphone) monitoring or talkback? Is that entirely separate?

Best regards,
Max

  • From: Sardinia
  • Registered: 2007-10-27
  • Posts: 11

Re: MOTU 24AI / AO compatibility

Thanks,

I've decided to tackle the monitoring / outboard problem as a separate step.
For the outboard I would rely on MADI maybe with a Ferrofish converter

For monitoring If AVB had acceptable interoperability something like Presonus EarMix or Motu Monitor 8 could be nice.

In other case, I'll go the MADI way and hook up some used MADI converter/stagebox by RME/Ferrofish/Soundcraft, preparing the cue mixes with TotalMix and use some compact 2/4 channels analog mixers for volume control.

The house that will hold the studio will not be completed before a year or two, but I like to plan ahead... maybe by then there will be more support for MILAN

4 Reply by gleeman (edited by gleeman 2022-02-19 05:22:50)

  • From: Sardinia
  • Registered: 2007-10-27
  • Posts: 11

Re: MOTU 24AI / AO compatibility

If I could suggest new products developments that would really fit my idea of studio

a) an AVB card with TotalMix FX including dynamics
b) A 24-in ADC with AVB or a 16 analog ADC + 1 ADAT port with AVB
c) a 12 to 16 channel DA with AVB for multichannel speaker setups including Dolby Atmos

5 Reply by damarco (edited by damarco 2022-02-19 18:17:44)

  • Registered: 2022-01-23
  • Posts: 27

Re: MOTU 24AI / AO compatibility

There is the well-known Milan problem. If you look closely at Milan, you will discover incomersibilities. Which, together with errors, lead to problems. The biggest problem is the changed procedure of the Connection. The user does not understand this. What you exactly do not work could be discussed in another thread. If there were no deviations, you wouldn't need the different modes.

Getting back to your topic, consider that RME offers you converters over 48KHZ with 32ch. The motu only has a 100Mbit interface and can then only transport 1 stream a 8 channels. Then the 16 inputs are worth nothing.

The devices should be able to be operated in the AM824 stream format with 8 channels. However, the RME interface must be operated in AVB mode -> (Digiface AVB) . Another thing you should keep in mind with Motu is that there will not be full IEEE 1722.1 support in the devices. There are instructions for this in the instructions. The RME devices have full IEEE 1722.1 support. At least we're working on it wink

I can only recommend the Digiface AVB, it works without any problems. You can also switch between AVB and Milan mode. The AVB tool only runs in Milan mode, which I regret sad. The other converters are probably similar.

  • Marc S
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Re: MOTU 24AI / AO compatibility

Primarily, Milan is about narrowing the scope of the huge standard set that AVB is made of (802.1Q-2018, which includes the former amendments 802.1Qat and 802.1Qav, 802.1AS, IEEE 1722 and IEEE 1722.1).
These standards give you a bazillion options to implement "AVB", which is great to make it fit for a broad range of industries, but not so good for interoperability within ProAV.
This is why the ProAV working group within the AVnu Alliance has been founded in the first place.
Apart from that, Milan adds missing parts, first and foremost redundancy.

There are three things, where compatibility between "legacy" IEEE 1722/1722.1 devices like the MOTU range and Milan compliant/certified products might be an issue.

1. Autoconnect
That's the Milan term. 1722.1 called it Fast Connect, which is, in fact, only half of what is necessary in ProAV settings. (...and was never intended to replace centralized or distributed controllers).
This has been fixed in the upcoming revision of 1722.1, which is going to be released soon. Nonetheless, too late for the first iteration of Milan, 4 years too late to be exact.

As far as I know, Motu implements its own reconnection mechanism, pretty much like one of the upcoming modes in 1722.1-2021.
It connects both its own Talkers and Listeners, whereas Milan devices only take care of reconnecting their own Listeners (which, if every device does this, is sufficient). But that in a very thorough way...
Milan has a slightly different command-response sequence, which might confuse some implementations (e.g. the current Apple AVB implementation), but most of the time it just works.
Worst case: stream is reconnected twice. So what?

2. Dynamic mappings
Milan requires dynamic mappings on stream inputs and allows dynamic mappings on stream outputs.
1722.1 allows both modes for both directions.
On our standalone converters, 12Mic, AVB Tool, etc, we are using dynamic mappings for the usual routing, so just use the web interface for routing and connect streams to Motu as usual. No incompatibility here.

3. Stream formats
as Marco said. All our devices support the legacy format, IEC 61883-6, better known as AM824, the modern format, AAF and CRF for clock streams. This can be used to transport audio between other, normally incompatible, devices.

So while we only officially support Milan on our converters at the moment, most of the time it will work quite well with legacy devices. If not, a post in this forum is usually a good starting point.

Moreover, I expect that Milan and 1722.1 will converge over time, we are monitoring those changes closely and will follow along as long as it makes sense.


b) A 24-in ADC with AVB or a 16 analog ADC + 1 ADAT port with AVB
c) a 12 to 16 channel DA with AVB for multichannel speaker setups including Dolby Atmos

We have M-32 AD and DA Pro and M-1610. Do you have considered these devices? If so, I'm curious about the reasons they don't fit the bill. Regarding the ADAT port, do you mean in- or output?

7 Reply by gleeman (edited by gleeman 2022-02-19 21:52:22)

  • From: Sardinia
  • Registered: 2007-10-27
  • Posts: 11

Re: MOTU 24AI / AO compatibility

Thanks for the lengthy explanation, now it's more clear.

We have M-32 AD and DA Pro and M-1610. Do you have considered these devices? If so, I'm curious about the reasons they don't fit the bill.

It's a simple economic reason. For a project studio I need just the number of channels to record a small band, 24 is enough. 32 would mean that most of the times there will be unused channels.
A MOTU 24 Ai device is most surely not the same quality as the RME M-32 AD converters but it's EUR 1200 instead of 3600.
I would rather invest in better microphones - at the moment - than in the best converters and I'm sure the music will not suffer much.

Regarding the ADAT port, do you mean in- or output?

I mean ADAT in (two S/MUX ports), to hook up one of the many devices with 8 inputs available on the market. For example I have a Tascam 8p that I could use without the pres. So I would have 16 channels of high quality RME conversion for most of the use cases and add 8 channels of "good enough" inputs at 96Khz.