Serious MIDI problems on Mac Laptop (i7 processor)

[Groovacious]

MIDI Troubles in MacBook Pro - "Hanging Notes" Galore - Help!!

To all Mac Users who may have experienced MIDI troubles in Apple's MIDI world:

I have started to use a MacBookPro (i7 processor) as my sound module about 2 years ago and have been ecstatic about the fantastic sounds I now could use on stage.

I used a multi-channel MIDI-capable masterkeyboard (various types) (Yamaha Motif series or S90 etc.) to control the various layers of sounds inside my laptop.

The latency is negligible and I began having great fun playing digital keyboards again with the artists I'm currently on the road with.

Then about a half a year or more, trouble started creeping in.
At first, a few notes would keep ringing and would only stop ringing once they were re-played. Using the sustain pedal had no effect on this at all.

This effect has increased to a point now that many songs are blasted by Note-Hangs --- and even certain notes seem to be "Stuck In The Pipeline", at times reappearing out of the blue (and not musically very satisfying to the artist) which is a totally new phenomenon for me.

I have worked for ROLAND as a product specialist and have been around Macs for 15 years, around MIDI itself for more than 27 years.

What Apple's OS os doing with this antiquated application is beyond me.

I welcome your feedback and intensely look forward to a solution that will enable me to bring my computer back into my music performance system.

Stephan Oberhoff
Professional Keyboardist and Music Producer


Specs:

MacBook Pro 2.66 GHZ
running Leopard 10.6.8
Memory 4GB

What have I tried:

Cleaned up all Ram Caches and Cleared P-RAM =NO EFFECT
Trashing Preferences on the AudioMidi Setup.plist (preferences)=NO EFFECT
Used other outboard gear as a Sound Module =NO EFFECT
Used another MIDI interface=NO EFFECT


Note-hangs occur with various types of software synths AND outboard MIDI sound modules.
The also oocur using different types of MIDI interfaces.

As SOON as I use the Mac in the MIDI chain - trouble shows up.



Another interesting effect: Sustain pedal weirdnesses recorded into GarageBand - must be related to the overall chaos in Audio Midi Setup....
http://www.youtube.com/watch?v=msFWfcZpWOI