Motu Ultralite and Buffer/monitoring

[vsukpadman]

Hi all

I have a new macbook pro (2.33/8 gigs ram) and am using a MOTU ultralite mk 3 interface.
Drive is a fast glyph attached to ESATA express card, so I have pretty much got this as fast as I can.
Why then will protools not play back for more than 30 seconds on a buffer size of 64 with only 8 tracks or so without the dreaded usual error?

Cpu is showing at 6% , Disk at 11% as an example , but still stops playback with the buffer error at 64

The reason I need it so low is that for the life of me I can't work out how to get Motu's Cuemix fx to allow me to monitor at low latency using its own mix routing,and I find the latency at 128 buffer distracting for singing.
..so - 2 questions

1) should PT be gagging at 64 buffer with this system ?
2) does anyone know a way to use the MOTU so I can monitor live mic input and hear protools returns elegantly?

Os is LION and running the new 9.05 PT (yea I know ! )

any help appreciated!

cheers

Bill P ..

[The Dougfather]

Is the hybrid connected via USB or firewire? With my 828mk3 I still daisy chain my firewire drive in to the interface, i simply don't trust USB for high bandwidth critical audio.

The purpose of the MOTU cuemix software is to allow to route your inputs to your outputs so that you can monitor incoming signals with near zero latency. In Pro Tools you have two options:

1) Do not use the cuemix software, reduce the HW buffer as low as possible to reduce any noticeable latency.

2) Use the cuemix software to monitor incoming signals so that you don't have to reduce the HW buffer.

The issues:

1) You cannot turn off software monitoring in Pro Tools, you can in Logic etc but not in Pro Tools, this means that Pro Tools will always kick back the digitised audio signal. For you to fully utilise the cuemix software you need to mute the record armed track and setup the mix in cuemix, a real PIA.

2) When running low buffers theres a saturation point when your start adding plugins VI's etc where you'll get the CPU errors, you can work around this by disabling tracks/printing etc.

Personally, i run with the low buffers and don't use cuemix. MOTU drivers are great and theres absolutely no reason why you shouldn't be able to run dozens of audio tracks at 64 samples, as said it's plugins and VI's that will catch you out. I had no issues doing this on a G5 with Pro Tools 7/8.

Make sure you follow all the system optimisations and specifically reduce processors by one in the playback engine for a smooth running system, also will the drive run with FW800, if so give that a try because Esata drives are not supported.

[sorcerer27]

Well another thing that wasn't mentioned is what samplerate your running your Ultralite at for the session? If you're doing 96Khz it's unlikely you'll get the Ultralite to handle a PT's hardware buffer size of 64, whereas, a sample rate of 44.1Khz should allow you to attain that.

[vsukpadman]

Thanks for the replies -

@Dougfather - The hybrid is connected on its own now to the one and only Firewire port on the Macbook pro via an 800/400 cable (good quality)..
Before (when I wrote the message) it was daisychained to the audio drive on the firewire bus .no better or worse it seems....
I have the drive now on Esata via a sonnet tempo pro expresscard , which has though given me BETTER drive performance over the firewire option
.
Even with this and Cpu now showing 3% drive 1% it STILL coughs with a -6101 error.- weird

I have been pretty much through ALL the optimisation steps and ,
No plugins..Playback engine 64 samples
7 processors
85% CPU usage...
Delay comp long .
Im beginning to wonder of it is Lion/9.0.5 beta related
Surely with the usage meter showing 3% , protools should not be erroring with a CPU overload!
@ Sorceror- all at 24 bit /44.1 khz....
I agree the cuemix fx is a ROYAL pain to work out what is going on !
Would MUCh rather run all from PT at 64 samples...but SOMETHING is stopping me from doing that !

any thoughts appreciated !

Bill P

[vsukpadman]

Eureka ! - (I think

I have tried running the session using ONLY the MOTU as the playback engine-
Before I was using AGGREGATE i/o as I had been using the built in playback as an output to check mixes on the small speakers sometimes (this output was NOT assigned to any tracks when I was having the errors)
I now seem to be able to run a session at 64 with no errors.!!!
I can also run at 32 on a 16 track sesssion- excellent
So it seems aggregate i/o was the culprit ! - interesting !
hope that helps others in this situation !

cheers

Bill P