Trying to record... Failing miserably

U

Uncle Humjaba

Limp Gawd
Joined
May 6, 2006
Messages
437
Hey all

So here's my rig:
* MXL 990 condenser mic
* Nady SMPS-1X phantom power supply
* Lexicon Alpha USB interface
* Cubase LE 4, Audacity

I can't get rid of this background noise: http://humjaba.com/bgnoise.mp3
I've tried it on both my laptop (on battery power) ...and my desktop; same thing. I hear the noise through the direct monitor as well as in the recordings, but only when the computer is accessing the device (i.e. when Cubase is running, or when audacity is recording). Otherwise, it sounds fine (through the monitor). Any ideas? Seems to be only when the driver is running do I have the problem. I've tried the Lexicon-supplied asio driver, as well as ASIO4ALL and get the same result.
 
I'm going to guess it's poor layout and a cheap DC-DC inside the phantom power supply, or maybe it's just faulty. Do you have any dynamic mics you could test without the phantom supply? Or at least try recording from the line-in.
 
Line 2 and line 1 both work beautifully. The front instrument panel works beautifully. I guess I'll have to wait to borrow a microphone from church on sunday to see if a dynamic mic works okay.

How could it be the phantom power supply if I can monitor myself without the software running just fine?
 
Uncle Humjaba said:
How could it be the phantom power supply if I can monitor myself without the software running just fine?
Click to expand...

Missed that part of your post :p

That is really puzzling, it's gotta be something inside the Alpha then, I would think. Line ins working seems to indicate the ADC section is okay, and the monitor working seems to indicate that the mic preamp is okay, so I'm really at a loss as to what it could be though. Have you contacted their support yet?
 
Yep, still waiting on a response. :S Everything else about the unit works magnificently. But something about sending data from the mic input over USB makes it flip out.
 
It is pretty characteristic of what USB 'sounds like'...

Does moving the cables around change it at all?
 
Wiggling changes nothing, swapping cables does nothing. I only have 2 XLR cables. I could try swapping out the USB cable... Perhaps the one I've got isn't shielded or something? But then it wouldn't work for other instruments...
 
It's not a USB sound, ive used loads of interfaces over USB and none of them have this kind of sound.
It does sound faulty, possibly a bad cable/wiring etc. Its around the electric tone pitch. So it might be a badly earthed cable/unit. Certainly sounds that way.

If the problem won't go away, you could use something like Izotope RX. It is great for removing noise from anything. It is expensive though. you can get a 30 day trial or something for a linux distro.
 
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