Live, MBP 11', and Fast Track Ultra: Vocal XLR Crackling

[fountain2]

It seems ever since I upgraded my laptop (from 09' Macbook Pro to 11' MBP) I am getting some "crackling" out of one of my speakers. When I run my vocal tracks and drums our of a single line out of my fast truck ultra (1/4 inch to XLR patch cable --> XLR cable into a powered speaker (Mackie Thump 400watt)), there is a crackling sound that appears ONLY when the line is being used (i.e. if there is no singing, there is no crackling, but If I sing a word, it has noise or if it picks up ambient room noises).

I do not remember this happening with my older laptop. Is this is latency issue?

Also, I am simultaneously running a line out into a separate amp for guitar and it is perfectly silent and sounds great.

My detective work (i.e. potential sources of the problem that I have now eliminated):
1) Patch cord is good (1/4 inch to XLR out of fast track ultra)
2) XLR cable to powered amp is good
3) Amp is good
4) Power is not an issue (just bought a sweet power conditioner)
5) Mic is good

Which leaves me to believe it's my new Macbook Pro 11'.


Please help! The crackling noise is distracting

[Yoseph]

Please help! The crackling noise is distracting

...and bad for recording. Set to a little bit higher sample rate in your audio preferences. If that doesn't work, reinstall the drivers for your audio device.

[Khazul]

Could have a flakey mac, but doubt it. Ive recorded huge numbers of channels through my UFX via USB2 without any problems. Generally run it at 44.1, 128 samples, though it seems good down to much lower.

Check you latency setting, try with it higher. Make sure have latest drivers for the audio interface, perhaps something wrong with the audio interface? Do you have any other hardware plugged into USB ports (not that I have found that a problem on this MBP)?

[fisto]

also try to enable/disable "high performance mode" of the FTU.
On my old xp-machine I had it enabled, because i had crackles without HP-mode.
On my current win7-machine I have HP-mode dis-abled as it works better so.

I'm not sure if there is such a pref on mac. But I use it also on my live-gig-mac (summer 2010) and there are no crackles.