problems using a USB hub for audio or midi

[tief]

First, my apologies if this topic has been covered elsewhere, though I haven't been able to find anything.

Can anyone offer an explanation or provide advice about the following?

My audio interface (MBox Mini) nor MIDI peripherals (MOTU Fastlane, Keith McMillen Softstep) won't function properly through a USB hub (powered or non-powered - currently using Belkin) on my MacBook Air (11' 2 USB ports). They work when plugged directly into the computer's USB ports. Have tried various hubs, and every other "normal" USB device functions without exception.

The audio interface is recognized but is so noisy that it is of no use, the midi signals seem to only work after many presses and then send multiple notes/messages.

What could the matter be?

Many thanks,


Charles MacInnes
trombonist|composer|sound artist
http://www.charlesmacinnes.com
PO Box 393, Yarraville VIC 3013 | Australia

[oddstep]

do they function if only one thing is plugged into the hub (so its effectively an extension cable). i wouldn't expect to share a usb port between audio and any thing else.

[tief]

Mmmm, it is behaving very strangely. The McMillen USB midi controller does work as you describe, but only as long as the MacBook Air isn't plugged into the mains (otherwise it's very noisy when you come close). The MOTU (and anything connected) only works when it's plugged in directly, and not through a hub.

I suppose I am discovering the limitations of using the Air for this sort of set up.

Thank you for answering!

[trevox]

Mmmm, it is behaving very strangely. The McMillen USB midi controller does work as you describe, but only as long as the MacBook Air isn't plugged into the mains (otherwise it's very noisy when you come close). The MOTU (and anything connected) only works when it's plugged in directly, and not through a hub.

I suppose I am discovering the limitations of using the Air for this sort of set up.

Thank you for answering!

For your noise issue, have a look at this thread:

http://forum.ableton.com/viewtopic.php?f=1&t=155619

Easiest, but not necessarily safest fix is to remove the earth from your macbook air plug. Is your hub powered separately or powered from the laptop? If it is powered from the laptop, it probably simply cannot provide enough power. If it is powered, it should provide enough.

[ericzang]

concerning noise, is it related to the softstep EL blue backlighting? Have you turned it off in the softstep software? I have a noise issue when it is on, as do several others as I understand.