MOTU 24AI - limited to 24x24?

[STUDIO|GIBON]

I understand and I understand... we also set up ethernet on the iMac 2012, but the settings had to be made manually - mainly it has to be 1Gb, which I think almost all computers have, even the older ones.

[HCMarkus]

IIRC, there are limitations re: Sample Rate when using the Ethernet-Mac connection. May or may not be an issue for some.

I think latency may be a tad higher via Ethernet as well.

[Funkstar De Luxe]

I’m not worried about sample rate, 48kHz is enough for me. Latency is fine too, as long as it’s consistent

[mikehalloran]

I understand and I understand... we also set up ethernet on the iMac 2012, but the settings had to be made manually - mainly it has to be 1Gb, which I think almost all computers have, even the older ones.

Gigabyte Ethernet has been the minimum standard for over 20 years. Although some Macs and PCs support 10G Ethernet, there's no mention of this in the 24AI specs or documentation — and you know it would be there if supported.

10G routers are coming down in price but I've not seen the need to upgrade mine — yet. When WD releases a 10GBE NAS box that supports Time Machine, that will be when for me.

[monkey man]

IIRC:

There's a small CPU hit but it's greater than what would be incurred when using USB or Thunderbolt.

[scstock]

I can’t see how it’s possible to increase beyond 24x24.

When I try to change the values of “from computer” or “to computer” beyond 24, they simply revert back to 24.

Am I doing something wrong? Or is there another setting I need to use? Have anyone actually achieved this with a MOTU 24AI?

Have you tried entering a higher number in the To Computer and From Computer fields?

[James Steele]

Gigabyte Ethernet has been the minimum standard for over 20 years. Although some Macs and PCs support 10G Ethernet, there's no mention of this in the 24AI specs or documentation — and you know it would be there if supported.

Correct me if I'm wrong, Mike, but isn't the issue when connecting a Mac directly to the Ethernet ("Network") port on a MOTU interface like the 24Ai is that you have to use a Mac that is new enough that either the hardware or OS (not sure) is new enough that it supports AVB directly? My understanding is it's not really plain vanilla Ethernet... but AVB... so not just any Mac will do.

Hold on! I just now looked though the 24Ai manual and found this:

04-Jul-2023.jpg (169.11 KiB) Viewed 1508 times

So the way I read this is it's not so much the OS that's an issue. I imagine most users these days are using Yosemite or newer. You just need a Mac that supports Thunderbolt. Apparently those models have an Ethernet port that is compatible with AVB.

I'm still digging to see what the limitations are of doing it that way. Couldn't find it in the 24Ai manual, but I'm pretty sure HCMarkus is right and there is a limitation on the sample rate and also some latency when compared with USB. I use mine as an AVB expander to my 828es which is connected to my Mac via TB2.

[James Steele]

Just went digging a bit more and found the info below at this link:

https://motu.com/techsupport/technotes/ ... imitations

Limitations Regarding Direct AVB Audio Connection to a Mac

While you can connect a MOTU Pro Audio interface to a computer running macOS 10.10 or later with just an ethernet cable, there are some performance drawbacks compared to connecting with USB or Thunderbolt.

Apple's current implementation of direct AVB audio streaming in macOS (first introduced in macOS 10.10) does not allow the use of third party drivers. You will not be able to use the MOTU Pro Audio driver when connecting your MOTU interface to your Mac via Ethernet for the purposes of multi-channel audio I/O. Using Apple's AVB audio driver has several limitations. These include:

1) Sample Rates of 44.1 kHz, 88.2 kHz and 176.4 kHz are not supported.
2) The MOTU Audio Tools application is not supported.
3) MIDI is not supported.
4) Increased latency between the interface and computer when compared to USB and Thunderbolt connections.
5) Audio MIDI Setup settings for the AVB device are not saved upon reboot.

What's interesting to me here is that you cannot use a sample rate LOWER than 48 kHz. You can't use 44.1. Your choices are 48, 48 or 48. Sometimes you can even do 48. Again, though, in practical terms that's not much of an issue. That's all I use now.

And yes... "increased latency... when compared to USB and Thunderbolt connections."

[James Steele]

Just read those limitations again and this might be the real dealbreaker:

5) Audio MIDI Setup settings for the AVB device are not saved upon reboot.

I'm not really sure what it would look like and what sort of routing for inputs and outputs you can do in the Audio MIDI Setup app, but according to this you lose the settings every time you shut down or reboot your Mac. Verily, that would sucketh mightily.

On the other hand, this technote appears to be very old and perhaps some of this has changed, like losing the settings, in more recent version of MacOS?

[monkey man]

I think it's more about the OS than the actual Mac hardware James, but I could be wrong.

[James Steele]

I think it's more about the OS than the actual Mac hardware James, but I could be wrong.

If you look at the requirements, it must be a Mac that has a Thunderbolt port. Sounds like a hardware requirement to me. Unless MOTU is using the presence of a TB port as an arbitrary indicator as to what constitutes a “recent Mac.”


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[monkey man]

Yep, the 2nd part of what you said is how I took it several years ago when I was researching this.

What I do remember 100% for-sure is that Apple apparently implements / ed ongoing tweaks to the OS in order to improve the performance of AVB over ethernet.

Also, call me dumb but I couldn't think of any logical reason why TB hardware would've had anything to do with it.

I'm betting Mike would have the lowdown on this; it'd great if he could spill the beans for us.

[James Steele]

Perhaps. I guess one way to know is put the same approved OS on a Mac with TB and one without and see if it still works on the one without. Why even mention the TB port at all? Just mention minimum operating system?


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[monkey man]

Only possible (and obvious) reason I can think of is to encourage sales of new Macs.

I'd expect better of Apple 'though so I hope Mike confirms that you do actually need the new hardware.

[James Steele]

Only possible (and obvious) reason I can think of is to encourage sales of new Macs.

Yeah... but this was in MOTU's documentation... not Apple's.