noise problem

This likely has more to do with the Behringer mixer than anything. Actually I had this very problem with a behringer mixer. It was awful. I got rid of it. (Don't mention the B word at some recording forums. They may get upset and give you a lecture. )

Now I'm not totally agains B. I just think that their quality control is a bit lacking. Some products work fine others or even another unit of the same item will be awful. That being said, you can expect to have a certain amount of hiss from the power amps in the KRKs.

If the master on the KRKs is up pretty loud, you will definitely hear hiss. Try keeping the volume at a more reasonable level. Maybe crank your output on the B up to about midway which you might think to be a good loud listening level without distorting the monitors. Then turn up or down the monitors to a level which you think is the absolute loudest you will ever want to listen at (don't make your ears bleed.) You may need to fiddle with the level at the mixer to make sure there is no distortion. Now once you've figured this out you can turn down the level at the mixer. There may still be some hiss but if it is so loud that it's annoying, you probably have the level too loud at the monitor. Either that or buy an Mackie Onyx.

Hi Kachman
Do you hear noise even when you reduce the input volume knobs?
I can only hear noise from my UB802 monitor/headphone out when I increase input volume level and gain on the mic inputs.

It is normally the hi gain mic pre-amplifiers in the mixers mic inputs that are the noise source as a very low-noise hi gain amplifier are costly and therefore not used in low-cost mixers.

The other amplifiers in the mixer that work at medium levels are easy to make low-noise and has therefore a low impact on the general noise levels.

Thanks guys,

I did some troubleshooting with my setup. Sounds like everything adds a lttle noise!!! I have to totally disconnect my soundcard "out" and my monitors and then turn down all input levels before things go quiet on the headphones. With "Ctrl" level set to the center, I plugged in components and turned up levels individually. Turning up the levels on any input with the behringer introduces some noise, but it seems worst with the monitors. Once I plug in the monitors without even turning them on, some low "whinining" can now be heard - it disappears when I remove the monitor wires again. These are balanced 1/4" to XLR cables so it can't be the cable. I don't think the monitors are bad either, so hueseph may have a point about the Behringer! But yes Kalle, it is low-cost afterall....

Hi Kachman
The "whining" you hear when you connect the monitors is probably due to a "mains" ground loop problem.
You can detect this if you connect the monitors to the mixer and then connect and disconnect the monitors mains cable from the wall outlet.
This is a classical problem when connecting several mains feeded sound equipments to each other.
Especially with the mains connector system used in USA, where you use a 3 pin connector system that locks phase, zero and "safety ground" to a connector pin position.

Most "home" sound equipment in Europe ( not UK) use a 2 pin connector ( without "safety ground") that is possible to turn 180 degree and thereby change phase and zero of the mains source.
This makes it easy avoid mains ground loop and hum problems.