Topic: Interference/Distortion in Audio file

Hello!
In the past month I've had the same distortion pop up in my live recordings twice. I've attached a link to google drive with a short audio clip displaying the obvious issue. This session was recording 3 mics, all at 24/96, with no effects. Just straight to disc recording. The noise is present in all three discrete tracks.

My interface is the rock solid RME UFX, and I was fortunately using the UFX's usb drive back-up(DuRec), which was clean of any unwanted noise.

I understand that this is in no way an issue caused by the UFX (in fact, the ufx was able to save the recording with Durec), but seeing as how this is such an unusual sound, I thought some of the brilliant minds on this forum might be able to help me pinpoint an issue.

https://drive.google.com/file/d/0B09jwg … sp=sharing

Macbook Pro (mid 2010)
2.4 i5, 8GB
3 mics to reaper, reaper to external firewire 800 drive.

Re: Interference/Distortion in Audio file

Thanks for the consideration, any help would be appreciated!

3 (edited by fl 2015-05-29 12:25:37)

Re: Interference/Distortion in Audio file

Since the DuRec recording is free of the noise, it's pretty clear that the issue is either with the connection between the UFX and the computer, or within Reaper itself.

Because its occurrence is intermittent, troubleshooting will be lengthy and tedious, but you may get lucky. The first step would be to swap out USB/FW cables to see if the fault lies there, or to try the "other" connection (if using USB, try Firewire - or vice versa), as the fault might be not the cable, but with either (or both of) the UFX's or the computer's connection point(s). If that is the case, you will need to have the offending hardware repaired.

The last place to look would be Reaper itself - could there be something causing it to lose sync with the incoming sample clock? Some other software which momentarily interrupts Reapers connection to the computer's audio hardware? You might want to try increasing the amount of processing latency used by the UFX, which you should be able to adjust within Reaper. Yes, you'll hear your incoming audio with more of a delay than what is happening in the room, but at least you won't have signal degradation.

A last thought - the quasi-rhythmic nature of the interfering sound reminds me of what can happen when a cel-phone is used in the vicinity of a recording device. You might try placing one right on top of your UFX and/or your computer to see if you can re-create the interference that way.

Frank Lockwood
https://LockwoodARS.com
Fireface 800, Firmware 2.77
Drivers: Win10, 3.125; Mac, 3.36