Help required with MOTU UltraLite Mk4 mixer

I am using a MOTU UltraLite Mk4 as my audio interface with 14 studio monitors (6 stereo pairs cycled as my main output, and one stereo pair for the surround channel), along with a sub-woofer. In order to provide enough channels I am also using a separate D to A converter connected to the ADAT output. The sub-woofer is connected to the headphone socket of the UltraLite so that it gets a mix-down of everything. Up to now this has been working fine.

There is an app running in a browser window to control the internal mixer of the UltraLite, and I have clearly inadvertently changed something as there is no longer any signal going to the headphones. The app has a patchboard to route the inputs to the outputs, and there is an additional default output called Main which is supposed to be a stereo mix-down of everything else - I have been routing this to the headphone output, but Main has fallen strangely silent so nothing is reaching the headphone socket.

The patchboard also has "lights" showing when and where a signal is present - for instance if I play a chromatic scale on a single stop the various channels light up in turn according to the cycling algorithm. For some reason, however, the lights on the Main channel, which were previously flashing with every note, no longer illuminate.

Also (I assume this must be connected) if I switch to the Mixer view, each channel has a vertical bar serving as a meter to indicate the level of the signal, and normally when I play these bars are active. However, they are not showing anything any more. Despite this, sound is coming out of the correct speakers as before, except the subwoofer, which remains silent. As well as the main verticle level slider control on each channel (which I have left at the default -0dB attenuation) there is a small horizontal slider to adjust the level of the signal going to main - I have not touched these and they are all at their default -0dB.

I am hoping there is someone familiar with the software who might have a clue as to what is going on. I am sure I must have inadvertently turned something off, but I can't work out what. I am not a sound engineer and I am not familiar with the intricacies of how mixers normally work, and I am hoping that somebody may see an obvious solution. Alternatively maybe I need to do a factory reset and I am not sure how to go about that, either.

The fact that the speakers are getting the proper signals only means that the proper signals are being routed correctly from the source inputs to speaker feed destinations.

These various (source) signals also need to be connected to the internal mixer inputs. A signal (source) can be connected to multiple destinations. In addition to the (output) destinations which drive the speakers, you also need to setup the internal mixer inputs as destinations as well. And then route the source signals to both.

Any chance you may have the main outputs muted on the internal mixer?
Probably not as no signals are getting to the internal mixer inputs.

Or any of the respective inteenal mixer pots set to zero? Probably not either. There is a pan control associated with each mixer allowing a signal to go either left or right by which ever way that is set.

BTW, you can also use a monitor mix to a designated destination to achieve the same thing provided that the monitor mix has the various channels connected in a stereo mix down.

On the routing screen, you should see along the top the sources and along the left side tall of the destinations with a box at the cross point showing that this connection is made.

If you saved a previous setup that worked properly, you could use that to restore the setup.

There is not need to do a factory reset, just a need for proper routing.

Perhaps this explanation from MOTU may help:
https://motu.com/techsupport/technotes/avbrouting

You can also call MOTU tech support and they can talk you thru the proper setup. Yours is a very common one.

617.576.3066
9am - 5pm ET, Monday - Friday

Rgds,
Ed

Sending signal to your unit's on-board mixer

Mix-In Channels
Your MOTU AVB interface is equipped with a 48-channel on-board digital mixer. Much like other large format consoles, setup is required to route signal to and from the mixer. The number of channels in the mixer can be defined in the Device tab (described in the Routing Tab Layout section), and once set, these channels appear as "Mix In" channels, numbered sequentially in the outputs section of the Routing Tab, as shown below.

Keep in mind, these are considered outputs, as the mixer is a destination to which signal can be sent from the Routing tab. This is an important distinction to remember.




Signal coming into your device from any source, (a physical input, a "From Computer" audio stream, an AVB audio stream, or even one of the Mixer's output busses) can be routed to one of the "Mix In" channels. Make a connection on the Routing Tab for an input channel carrying signal, (Mic/Inst 1 in this example) and the Mix In 1 output channel.

https://motu.com/techsupport/technotes/images/avbtechnote/mixin1routesmall.png

Rgds,
Ed

Ed,

Thank-you for your detailed and helpful reply. I routed a duplicate set of outputs to the mixer, and this solved the problem. I hadn't realised that the "Main" output came via the mixer. I don't think I would have thought of it on my own.

Apologies for taking so long to get back to you - I have been away from my HW set-up for nearly a fortnight.

A big cheer goes up for you. Always glad to see success.

You can create multiple routing images, save and go back to them.depending on what you want to try.. Very neat setup.

Rgds,
Ed