AVB - Mixer - things not documented in the Manual!

[janzoulou]

I recently went int the AVB - world. I come from PCI 424 with 3 X 2408MKIII and mixing into 48ch analog summing....
Now I own a 122D and an 24o.

What is not documented at all in the manual, nor the Motu-Website is the following:
the channel count of the mixer reduces in relation to the samplerate! If I go higher than 48kHz the channels are reduced to 32 and the aux-channels are reduced to only 3 stereo!

I think this is a shame as it is nowhere communicated official.

It is also not possible to disable all the other stuff like MADI or the FX-section (EQ, COMP, etc)

So if I want to send something (like the mic from the vocalist) twice to different destinations without latency my setup gets really complicated...

Also if you have more than one interface you can not combine their mixers. Each item has its separate own one and one can not combine them to a bigger one.

Any thoughts?

[Klaus]

The same ( cpu usage ) applies to multiple boxes, here i.e. multiple 896mk3s
I only discovered it when the additional 896mk3s arrived...at the time...

Best

Klaus

I recently went int the AVB - world. I come from PCI 424 with 3 X 2408MKIII and mixing into 48ch analog summing....
Now I own a 122D and an 24o.

What is not documented at all in the manual, nor the Motu-Website is the following:
the channel count of the mixer reduces in relation to the samplerate! If I go higher than 48kHz the channels are reduced to 32 and the aux-channels are reduced to only 3 stereo!

I think this is a shame as it is nowhere communicated official.

It is also not possible to disable all the other stuff like MADI or the FX-section (EQ, COMP, etc)

So if I want to send something (like the mic from the vocalist) twice to different destinations without latency my setup gets really complicated...

Also if you have more than one interface you can not combine their mixers. Each item has its separate own one and one can not combine them to a bigger one.

Any thoughts?

[EMRR]

Yeah, you know this is you've read the entire 100+ page gearslutz thread, but not otherwise. The promo materials and manuals should be updated.

[janzoulou]

Yeah, you know this is you've read the entire 100+ page gearslutz thread, but not otherwise. The promo materials and manuals should be updated.

I think it should have been communicated from the beginning. What they state on their website is just wrong.

I hope a future firmware update will fix this so one could at least decide to drop some other mixer-features (comp, EQ Reverb) and aim full channel count and aux-channels even with higher sample rates.

What is also confusing that it isn't possible to route an output from the computer and and an input from an interface to the same output, like in cuemix, which was so straight-forward-easy.
If you want to do that you have to go via the Mixer, even with your DAW outputs. I got 48 outs to mix into analog summing... Now imagine recording a band with 24 signals and doing HP mixes ... omg, thats not easy. Or do I miss something here?

[EMRR]

You are, unfortunately, exactly right in your observation. The easiest way always comes back to using the AVB mixer for everything, but it becomes impossible at certain track counts and sample rates. Not exactly 'professional grade', somewhat an operational step backwards from the PCIe line of products. I've lately been trying to conjure multiple headphone mixes out of my system for initial tracking and overdubs, and with the way I work (analog mixer) I run into the same problem, in that all outputs must also have matching AVB mixer assignments to feed headphone mix busses, and at 88.2kHz there aren't enough inputs available.

I agree as well, a simple 2 to 1 combiner module would be a life-saver for this and several other interface problems.

Going further back, MOTU failed to mention in any clear wording that Direct Hardware Playthrough didn't work in AVB. They did amend the manuals to address this after much user consternation, that was a nasty surprise to discover after receiving the interfaces, and another aspect I find fails the 'professional grade' test.

[janzoulou]

I am in contact with Brian from motu - support (contact is a good word for that, one answer a day...)
and he even does not understand what I am talking about. Did you get back to them about that?

Honestly, if I would have know that, I definitely would have looked closer to other manufacturers like Universal Audio and Apogee.

The only thing that kept me from giving the items back, is the fact that they sound much better than the 2408 mK 3´s (I had 3 in my system feeding my 3 RME 8QS). Now they are connected via AES EBU and this is much more stable and sounds "quiter" than ADAT light pipe.

Thanks for your words, makes me at least not feel totally stupid.

BTW: What they write on their website:

"Destinations include interface outputs, host software inputs, mixer inputs, or any other device (or computer) on the AVB network. You can even split any single input (or stereo pair) to unlimited multiple output destinations."

That just is not true...

[janzoulou]

Update:
There is a hint on their website. I was in contact with Brendan from Motu-tech-support. He found this for me:
http://motu.com/avb/avb-faq#q14

I asked if it will be possible in the future to free up DSP for more channel / auxilary - counts in the AVB mixer with eg. switching of other features like reverb or EQ/compressors.

So far he did not answer that.

Cheers, F

[fokof]

I don't know if it's been added lately but I saw this :

"112 inputs and 112 outputs (224 total) at 1x sample rates
80 inputs and 80 outputs (160 total) at 2x sample rates
16 inputs and 16 outputs (32 total) at 4x sample rates"


http://motu.com/products/avb/112d/specs.html


( Total I/O )

[janzoulou]

I don't know if it's been added lately but I saw this :

"112 inputs and 112 outputs (224 total) at 1x sample rates
80 inputs and 80 outputs (160 total) at 2x sample rates
16 inputs and 16 outputs (32 total) at 4x sample rates"


http://motu.com/products/avb/112d/specs.html


( Total I/O )

We were referring to the AVB mixer, not the interfaces themselves...