General AVB questions

[revi]

Hello!

I'm looking to replace my PCI-424 based interfaces (2408mk3 and 24I/O). I am completely new to audio-over-ethernet (though reasonably familiar with computer networking and ethernet).

I only need analog outs right now as I'm mixing down into an analog mixer.

It seems that the 24Ao interface might be a really good fit. I'm trying to sort out some details:

1.) Are there any considerations or caveats regarding directly connect the 24Ao to the host computer using ethernet? I would appreciate input, particularly as regards the practicality of this approach.

2.) Specifically, it appears there may be some performance drawbacks - unfortunately, there's no date on this note:

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

3.) Would it be better to connect via USB-2 and, if so, what would be the longest suggested cable length?

One of the reasons I'm attracted to the AVB boxes is avoiding the "tethering" that came with the PCI-424 firewire cables. They were pretty long but it was inconvenient.

Your suggestions and insight are greatly appreciated!

Iver

[HCMarkus]

I think Item #2 pretty much answers your Question #1... for mixing, it looks like the limitation to sample rates that are a multiple of 48k and the inability of Audio/MIDI Setup to recall assignments could be a problem.

Generally, USB 2.0 (the protocol used by these devices) is limited to 16 feet, IIRC. You can get around this by using active cables/extenders or, possibly, a hub in the middle. I use a 15 or 16 foot USB cable to get from my control room to my computer machine room. USB works perfectly for me for my 828es.

[mrgkeys]

Dante is a better fit for distance than AVB, but that cuts out MOTU boxes. I use Dante with lengths more than 300 feet weekly. AS a note good ole copper XLR runs ok about that long. Any of the digital boxes Dante or AVB/AES50/etc does the conversion there post mic pre. What's your use case?

[revi]

Thank you both for the info!

Yes, I was admittedly wishful and that someone was going to say, "No, a direct ethernet connection will work fine with AVB!"

This does not appear to be the case.

I've got a smallish set-up and am only working with a few people. My "room", such as it is, is quite small and I'm looking to keep the interface close to the mixer. I'll be using 3 DB-25 breakout cables with the A24o.

One minor annoyance with the earlier interfaces (e.g., 2408, 24i/o) was that the jacks did not work well with the "bigger" plugs that seem to be the standard now: Jumperz and Mogami use larger plugs than Pro-Co, for instance. DB-25 outs eliminate that problem.

Dante appears to be the go-to for audio over ethernet but being able to avoid the Dante licensing fees was very attractive. If I was going to go Dante, I'd be tempted by the Ferrofish boxes...but they're either 16 or 32 outs, missing the 24 out "sweet spot" I was looking for and coming in around $2K+ and $3K+.

I'm going to go with the USB extension approach (i.e., with a [powered] hub between the computer and A24o)

Mac -> USB -> hub -> USB -> A24o

...though I may add an M64 at some point to go with a set-up ala:

Mac -> USB -> M64 -> ethernet -> A24o

My question was motivated by the goal (i.e., "hope") that I could just run a longish (i.e., not by networking standards, just 25 feet or so) ethernet cable so I could snake it around furniture.

Again, thanks for the input!

Iver

[HCMarkus]

Thanks for getting back to us. Good luck and Happy New Year!