Static and/or high pitch hum

amichels

New member
Hello!

Years ago I did a podcast and was able to record it without issue using my Behringer Xenyx 1204USB soundboard, and my MacBook. The MacBook I had at the time had an interchangeable "headphone jack," in that it could be used as either input or output. So, I would set the jack to input, plug in a 1/8" to 1/4" cable, plugging the 1/4" end to a "Control Room Out" jack on the board. And then I would simply plug in the USB cable for the board into the Mac. So, my input was set to "Internal," which was technically the output from the soundboard, and my output was set to "USB." This allowed everything I did on the Mac (sound effects, etc) to go through the soundboard, along with my mic's, and back into the Mac through the input jack.

Then Apple did away with the interchangeable jack. And now I have a Griffin iMic. I'm basically trying to do the exact same thing, although now the 1/8" end goes into the iMic, which then plugs into another USB port. So my input is "iMic" and my output is "USB."

While I can record, I am now noticing a distinct high pitch hum, along with static, in the background. It's pretty overpowering actually.

I used to record this way just fine, and then had to pack up my studio for a while. Now that I've put it all back together, this problem has started. Any thoughts? Bad iMic?

I'm attaching a sample of the noise...View attachment example.mp3

Thanks!
Andy Michels
 
Not familiar with the iMic, but the hum/whine is typical of low dollar A-D converters (many USB mixers have the same issue - by keeping output volume low on them, the whine is not too noticeable).
 
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Oooo! Nasty!

Yes the very typical crap USB audio noise. AFAIK it cannot be gotten rid of but that is only at around -43dBFS and that's terrible.

I don't know macs but on a Win PC you would open the Sounds Device menu, find Recording,,Levels and crank it down to 5% or less (0% gives you FA).

Now you will have to record hotter but run playback quieter and thus push the noise into the analogue noise floor (but you will always see it on a Speccy Anny) .

Has to be said, the Behringers are not bad MIXERS for the money but a poor choice for home recording general use (not at all bad for recording a band in a noisy pub mind!) .
What you really need is a decent Audio Interface so you can run at 24bits. One of the best for the money is the Steinberg UR22 but if you can stretch the budget a bit more, get something with more line inputs and put the mixer to the use it was intended.

Clarification! I said the noise was at -43dBFS and it IS on Samplitude's (lovely!) meters but you can see the spikes only reach -84dB on the spectrum? This is a quirk of RM analyser and if I am being really geeky I put in a calibrating tone. Note that the ultimate noise floor of all these 16bit USB devices that I have tested is about -85dBFS, some 10dB short of the theoretical (CD) limit but in practice perfectly adequate. The downside is that you have to record a bit hotter and thus watch those peaks!
Dave.
 

Attachments

  • Spec beryy zizz.png
    Spec beryy zizz.png
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