Unstable i2M / USB issues

The i2M musicport™ MIDI Converter & Hi-Z USB Audio Interface

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renzovar
Posts: 2
Joined: Thu Sep 01, 2011 1:26 pm

Unstable i2M / USB issues

Post by renzovar »

I have just started using the i2M with the following hardware :
MacBook Pro (i5) 8GB, RME Fireface UFX, Logic Studio 9, Apple Bluetooth Mouse

With the UFX is connected via USB, i2M (USB), and an iLok on the remaining USB port, the i2M is basically unusable (latency, glitches, missed notes etc.). Also, the bluetooth mouse stutters/ is unresponsive. I swapped the various devices between the ports but I couldn't achieve stability. Finally, I connected the Fireface UFX via firewire. The i2M is now usable! The mouse behaves.

Has anyone experienced similar issues?
It appears that there is a driver conflict or USB overload(?) when the audio interface (RME) is connected via USB.
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james
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Posts: 1866
Joined: Fri Jun 06, 2008 8:12 pm

Re: Unstable i2M / USB issues

Post by james »

It sounds like the USB bus is being overloaded so it can't handle the required low-latency transfers.

With USB, the bandwidth is shared between devices on the same "root hub". If you have multiple root hubs, it should be possible to connect the UFX to a separate root hub and avoid the problem. Often, different USB ports are routed to different root hubs. But, maybe all your USB ports are sharing the same root hub, so even changing ports isn't helping.

It could also be a driver issue that is tying up the interrupts on the CPU so it doesn't have enough time to process other devices.

Sorry I can't offer anything more specific.
renzovar
Posts: 2
Joined: Thu Sep 01, 2011 1:26 pm

Re: Unstable i2M / USB issues

Post by renzovar »

Thanks for the rapid reply! Fortunately, I can connect the the UFX via Firewire or USB.

Just one more question :

How does the performance of G2M compare to the i2M?

The G2M would solve my USB problems (and is usable without a computer). Of course the i2M has some nice features and is configurable. Both devices in my kit is not ridiculous ...

Finally, I'm impressed with the performance of the i2M. Well done.
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james
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Posts: 1866
Joined: Fri Jun 06, 2008 8:12 pm

Re: Unstable i2M / USB issues

Post by james »

How does the performance of G2M compare to the i2M?
The G2M (version 2) has the same performance as the i2M in it's default "guitar mode".
Finally, I'm impressed with the performance of the i2M. Well done.
:D
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