Excessive noise in signal, 8Khz hum

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chimheil

New member
I recently helped someone set up some recording equipment remotely. They are in a different state so I cannot actually play around and maximize their settings. They are using a Behringer Q1202USB mixer which is hooked up to his PC with the USB cable. He has 3 Behringer C1 mics. His signal is relatively noisy and there is an 8khz buzz in the left channel and a 6khz buzz in the right channel. Channel 1 is panned to the left and channel 2 and 3 are panned to the right so I can at least have two separate channels to work with.

He uses Audacity to record and then sends me the files to edit and I can do some cleanup in Audition but I would prefer to not have to clean it up as much. This is what his signal looks like. His input volume in Audacity is .6/60%.

https://i.imgur.com/SB4nHpR.png

And this is what it sounds like https://drive.google.com/file/d/0B94...ew?usp=sharing

And this is a picture of his settings. I use an Alesis Multimix 4 USB at work and a Behringer x1204 USB at home with similar settings and I do not get this much noise in the signal.

https://i.imgur.com/y34cHRo.jpg

I do see I need to have him center his EQ knobs but that's not causing the noise. Any thoughts on what exactly is causing the noise and 6/8k hums?
 
Hi,
It's strange that he's getting a different frequency of noise in each channel.
Are the mics near any noisy equipment like lighting or fans, or even gear with transformers?

I wonder, could you get him to plug in one mic only and do a recording while he slowly moves the mic around the room?
 
Steenamaroo said:
Hi,
It's strange that he's getting a different frequency of noise in each channel.
Are the mics near any noisy equipment like lighting or fans, or even gear with transformers?

I wonder, could you get him to plug in one mic only and do a recording while he slowly moves the mic around the room?
Click to expand...

If push comes to shove I can always notch filter out the buzz. Its just vocals and I'm pretty sure he is getting broadcast on an AM station but I still want as clean as possible. I'm not as concerned with that as I am the overall noise in the signal. Would I do better to have him raise the gain even more and lower the level faders? Or could this be a USB issue?
 
Your audio clip isn't available so I can't listen to it, but there's bound to be a reason for this.
Like I say, the fact that he's getting a different frequency per channel is odd. That would make me want to test and move each mic, one at a time, to try to rule out environmental issues.

If I set a condenser mic on my desk to my left and record speech I'll get a pretty loud buzz going on because my interface (with internal transformer) is about 8 inches away from the mic.
If I set the condenser on the other side of the table I get a good clear signal without buzz.

It'd also be interesting to get him to test with another source. An instrument or dynamic mic, for example.
I wouldn't be just so confident about that, but it's worth trying out.
 
That second link works. Thank you.

chimheil said:
He uses Audacity to record and then sends me the files to edit and I can do some cleanup in Audition but I would prefer to not have to clean it up as much. This is what his signal looks like. His input volume in Audacity is .6/60%.
Click to expand...

What does this mean? Is that a software attenuator?
If so, set it to 100% which should let him turn the mixer gains down a bit.

Try a different USB cable and USB port on the computer. Does no harm to try. Even try a different computer, if possible.

You mentioned the eq. Do get him to set all of those to 0 and try again, just to rule it out.

And finally, get him to make sure he's got the correct, up to date, drivers, and that his device selection in audacity checks out.
I'm not really a windows guy, but I know sometimes there are different options available for the same device. Again, worth a look.

Beyond that I'd simplify the setup bit by bit to see if anything changes.
Remove two of the mics and try again. Unplug necessary computer devices and try again. (USB devices).
Turn off any necessary equipment in the environment and try again.. Monitors, lighting, fans...anything at all.

Edit: That speech test sounds awfully ambient for being 1" away from the mic.
He's not treating it as end-address by mistake is he, or talking into the back of it?
Sorry - Not calling the guy stupid but it has happened before.
 
Yes, the .6 would be an attenuator. Oddly enough, I've actually gotten worse results in my tests here with it at 100. And he is just really soft spoken. He is not talking into the wrong end. I have run into people before who have done that. I will call them stupid because I sent them pictures and even a walkthrough video of talking into the mic and they still mess it up. I deal with a lot of old people who use their "I don't understand technology" as an excuse/crutch to not care or learn how to properly do things. On top of that they are across the country so I can't just go to their office and set it up for them and do my own independent testing. Its usually over the phone and screensharing trying to diagnose problems.

The bad part of this guy which I already know is going to happen is that basically he talks quietly and I am going to assume the other two people on his show are going to be much louder so their levels will probably be the same as his in the recording. I'll poke around and try to figure something out.

I wish Audition was free. Or I wish Audacity wasn't so stupid. One of the two.
 
Does he, by chance, have an old CRT monitor? Or is he near an old TV set? That almost sounds like video whine.
 
Without listening to the soundclip, I suspect what you've got there is the inevitable low-cost A-D converter noise. Why its at different frequencies on each side, I don't know. Almost every USB mixer has this issue. Some have USB volume controls (like my Mackie) and as long as you keep the overall USB volume (either in or out) down at about 11 o'clock on the knob, the noise is low. I don't think the Behr has such a knob, the USB output is at the same level as the main output.
 
This model does not have USB output controls. My x1204 doesn't even have one. Would I be better served to set him up with a stereo 1/4" to 3.5mm cable to his line in port rather than USB?
 
I would try all the stuff I listed first and answer Farview's question.
Yes, USB mixers are known to have noise/whine issues sometimes, but that whine is pretty loud.

There's plenty of troubleshooting you can do before writing it off.
 
chimheil said:
This model does not have USB output controls. My x1204 doesn't even have one. Would I be better served to set him up with a stereo 1/4" to 3.5mm cable to his line in port rather than USB?
Click to expand...

No, the best alternative is dump the Behr mixer and use a proper audio interface.
 
Steenamaroo said:
I would try all the stuff I listed first and answer Farview's question.
Yes, USB mixers are known to have noise/whine issues sometimes, but that whine is pretty loud.

There's plenty of troubleshooting you can do before writing it off.
Click to expand...

True, troubleshoot first, dump later! But the whine can be VERY loud when you crank up the USB output, believe me. When I tried a behr mixer and an SM57, I had to crank its gain way up, then the output volume and the noise through USB was so bad I returned the mixer the next day.
 
Here's a strange question....What does a ground loop through a usb connector sound like? It wouldn't be 60hz hum, because its a digital connection...

Unground the mixer and see what happens. (probably nothing)
 
If all the kit is on the same plug/power extender then you wouldnt get a ground loop. Make sure the computer, mixer and any other audio equipment are all plugged into the same thing and it would eliminate a ground loop as the problem

My best guess is that the pre-amps are being driven hard (it's quite a cheap mixer, not a huge amount of clean gain available) - if they're at different gains but both drivn relatively hard this could account for the different tonal makeup of the noise. As a general note as well, try getting him to record with lower gain (so it'll be quieter when he records) then boost it up digitally later.

Placing the mixer as far away as possible from the computer/screen might also make a difference.
 
I sent him some suggestions to try. Waiting to hear back. That's the trouble with remotely setting up people :/
 
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