Cycling 74 » Topic: Can I route audio channels on a MOTU 828Mk 3 from Max?

Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Wed, 14 Dec 2011 04:36:28 +0000

I don’t have my 828 handy but am trying to understand if it’s possible to define audio routing the same way one defines midi routing, i.e, can I create input and output audio objects and control which inputs and outputs with which they’re associated?

For example, on my 828, I have outboard synths connected to different inputs. I’d like to be able to arrange for the audio of each of those synths to be processed through different VSTs (say) and then sent back out through the Main outputs.

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

Junk Rhythm — Wed, 14 Dec 2011 06:09:48 +0000

Yes, this is possible.

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

commathe — Wed, 14 Dec 2011 07:22:03 +0000

Yeah, it should totally be possible. The dac~ and adc~ objects can both be set to use multiple channels. You can’t use the ezdac~ and ezadc~ objects as far as I know though. Also, the arguments you add will only tell the object to receive or send from specific channels. For example: “adc~ 4″ will only pay attention to input 4 on whatever audio source you are using. “dac~ 1 5 12″ will output what comes in its left inlet to channel 1, what come sin its middle to channel 5, and what comes in its right to channel 12

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

Roman Thilenius — Wed, 14 Dec 2011 09:16:31 +0000

last but not least it is not really needed to reroute the hardware in/outs – you
can as well do the routing prior to sending a signal to output 3 and 4 using gate~
or selector~. this wont interrupt the audio and it cant cause trouble to the
device driver, either.

-110

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Wed, 14 Dec 2011 13:40:00 +0000

I’ll play with it later tonight then — I guess I’m a little confused about what routings are happening “outside” of Max. Right now, I’m using CueMix to route all the inputs to the MainOuts — am I supposed to just turn those all off?

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

Roman Thilenius — Wed, 14 Dec 2011 17:01:23 +0000

what you find in the DSP settings is “outside” of your max patch. :)

i would set those to “normal” (output #5 is motu output #5) and route stuff only to output #5.

(except when building a standalone)

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Wed, 14 Dec 2011 21:19:44 +0000

OK — the value of Max/MSP just trippled (if not more) for my purposes.

It’s beautiful to be able to just wire my keyboards into Max, have them be processed by various VST effects and then sent out again. I’m not even noticing any latency.

I may not be able to go to work again until I’ve finished experimenting with this.

Thanks for the very useful comments.

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Thu, 15 Dec 2011 01:13:17 +0000

I’ve just finished reading the sections about audio processing, adc~ and related objects and I have a couple of questions

On the 828, it is possible to set the input gain (or attenuation, not sure which it actually is) for each channel via the cue mix software, implying that it’s software configurable. How can I set those from max so that I can balance all the inputs?

Secondly, I note that from the DSP Status object, one can select only a single core audio device. What happens if I have more than one? I vaguely remember something about aggregate input devices from years back but not sure if that’s the only solution? Can I specify a specific input/output device with individual adc/dac objects similar to how one does this for MIDI devices with midiin and midiout?

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

Junk Rhythm — Thu, 15 Dec 2011 01:28:43 +0000

Which operating system are you working with? If you are on OS X it’s fairly easy to setup under the Audio MIDI setup. There is an option to add a new aggregate device and the process is straight forward from there. If you still need help, I can walk you through it later this evening when I’m near a computer.

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Thu, 15 Dec 2011 01:39:12 +0000

I am on OS X and I remember setting up an aggregate device a few years ago, so I’m sure I’ll be able to figure that out. I do however REALLY appreciate your offer of help. I wonder if there are any latency consequences of creating aggregate devices though.

I’m more concerned about the problem of being able to set the input levels.

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Thu, 15 Dec 2011 05:35:38 +0000

OK — I think I need some help.

I have setup an aggregate device. The 8Pre is connected to the 828 via an optical cable.

The main outs going to my speakers are on the 828 and they appear on ports 21/22 in a dac. Four of my external synths are connected to analog inputs on the 828 and the fifth, a minimoog, is connected to analog inputs on the 8Pre.

I have successfully created a simple patcher where there are individual adc~ objects for each of these inputs and they are connected to individual dac~ objects (all of which have 21 22 as their arguments).

This works beautifully….for a while. After a couple of minutes, while the first four synths continue to play perfectly fine, the minimoog starts to produce more and more noise as I play it. If I disconnect that adc~ from its dac~ and then reconnect them, the minimoog sounds perfect again, for a couple of minutes, then the problem repeats. The other synths continue to work perfectly fine.

I’m completely baffled by this.

Any ideas?

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

Roman Thilenius — Thu, 15 Dec 2011 07:38:10 +0000

it is tempting to use the motu ffor things like that, because it is a full featured mixer – but i
woldnt do it, i would set everything to 0 db/A and control the volume totally from my max patch.

controlling the motu software from a max patch is not possible anyway, but a simple [*~ 0.25]
before your [dac~] will also lower the music volume to -6db/A.

you WILL be able to do all the things you want, but a little bit of programming is required when
using a programing language. :)

about the gain problem with the moog, no idea. can be your fault or the device drivers. what happens
with other synths on the same in/out ports and max patch?

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Thu, 15 Dec 2011 12:15:11 +0000

Yeah, I understand the use of gain before the dac. The issue is that some of the inputs are hotter than others. I’ve asked MOTU if they’d be willing to share any info on controlling the 828 through an SDK or other API. I have no problem creating a Max external to do the low level work if necessary.

The noise issue happens no matter what is connected to that set of ports. It’s hard to see how the problem could be related to the patch, it’s pretty trivial (patcher is below) done with Max 5.1.9. I can’t use Max 6 yet on my production machine as it tends to crash too much.

It’s also unlikely to be a device driver issue since the exact same physical configuration works fine when using the MOTU CueMix application.

I’m wondering if I screwed up the creation of the aggregated device, but if so, then I don’t know how I’m supposed to configure it.

(So close and yet….)

– Pasted Max Patch, click to expand. –

Re: Can I route audio channels on a MOTU 828Mk 3 from Max?

dhjdhjdhj — Thu, 15 Dec 2011 15:06:52 +0000

This problem is solved. Turns out that it was a sync issue. When creating the aggregate device, I had to check the box called “Resample” for the 8Pre and now everythin works wonderfully.

Thanks again for the advice.