Hiss from q802usb

[andybeech]

Hi so I got a new behringer q802usb as I wanted a mixer or audio interface for my bm700 condenser microphone as it was connected to my sound blaster z, but wasn't quite powering it properly and had a hissing sound in background. Now I have connected the q802usb via USB to the back of my pc connected the microphone to first channel via xlr cable. The microphone is set to 0 and main output is set to 0 so on basically, with a little bit of gain as it's too quite otherwise, the only problem is im getting a hissing sound in the background and the noise is still there even with no gain. I mainly do live streaming so cutting the noise via audacity is not possible, also I have tried a different cable but still get issues and a different microphone too. Any ideas thanks 

[anothertom]

First, let's fix your gain structure, as that won't be helping things. Due to how noise works, you want to amplify the signal as close to the source as possible. So, the output of a microphone is at about -30dB, so set the gain somewhere around +25dB, remembering that you want phantom power on (as you've got a condenser mic) and that you're using the outside values written on the mixer for reference. Adjust the gain so that you don't clip the channel when talking.

 

Now, depending on if you're using other inputs or not, there are two ways to deal with the next two stages.

 

Using Other Inputs

If you're using other inputs for anything, then you'll want to be able to mix them relative to each other, so set the main output at ~0dB and then adjust the channel level until the main output peaks somewhere between 0 and +6 dB.

 

Not Using Other Inputs

If you're not using any of the other inputs, why did you get a mixer?

 

I jest, but there are better options for a single input.

Set the channel level to 0, and adjust the main level so that it peaks around 0 to +6dB.

 

That should help a bit, but if you're still suffering from unwanted non-ambient noise then i would first look at USB power settings to make sure it's not being under powered, and then look at the nice troubleshooting guide provided by our lord and savior SSL.

[andybeech]

19 hours ago, anothertom said:

First, let's fix your gain structure, as that won't be helping things. Due to how noise works, you want to amplify the signal as close to the source as possible. So, the output of a microphone is at about -30dB, so set the gain somewhere around +25dB, remembering that you want phantom power on (as you've got a condenser mic) and that you're using the outside values written on the mixer for reference. Adjust the gain so that you don't clip the channel when talking.

 

Now, depending on if you're using other inputs or not, there are two ways to deal with the next two stages.

 

Using Other Inputs

If you're using other inputs for anything, then you'll want to be able to mix them relative to each other, so set the main output at ~0dB and then adjust the channel level until the main output peaks somewhere between 0 and +6 dB.

 

Not Using Other Inputs

If you're not using any of the other inputs, why did you get a mixer?

 

I jest, but there are better options for a single input.

Set the channel level to 0, and adjust the main level so that it peaks around 0 to +6dB.

 

That should help a bit, but if you're still suffering from unwanted non-ambient noise then i would first look at USB power settings to make sure it's not being under powered, and then look at the nice troubleshooting guide provided by our lord and savior SSL.

Thanks for the very detailed guide I will certainly try what you have said. Also I got

a mixer with opportunity to expand inputs and microphones if I need to saving money later on, also I noticed the boss noise is there even with no input plugged in and with just the board powered without USB being in pc? As well as the power connection seems to come loose as well, why would there still be a hiss if it's not got anything in inputs. Thanks

 

Edit: could be possibly my microphone as plugged in with phantom power off a imp.600 microphone a cheap karaoke microphone and there appears no hiss only when recording in audacity you can hear it. Or could it be phantom power causing issues.

Edited January 29, 2017 by andybeech
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