Muddy sound coming from VS1880s aux sends

I have my Aux 1 output no the back of my 1880 hooked into the Analog Ins on my mpc4k. I was trying to essentilly boucnce all of my tracks down to the mpc. I have audio in, everything seems to be fine, but when I playback the sample, it's extremely muddy and the bass is very, very loud. I then tried plugging in my keyboard to see if it was something in the mpc, and the keyboard sounded very clean.

Also, I have to turn down the aux sends on the channel page on the 1880 to around 20 on the levels, which seems weird. Anything louder clips really, really bad.

Any thoughts?

I'll have to look at my vs1880. Why aren't you using the main outs or the headphones out to see the difference?
Peace
ian

For some reason I hadn't tried the monitors, I did try Aux 2.

I have now tried Aux 1, 2 and Mon and Master, all are muddy.