I've had this mixer in my studio for a while but I never actually took the time to get it completely up and running. This is due to the fact that I have had the same problem in the past as I am having now. A few certain sources when plugged into the Mic or Line inputs, will sound perfectly fine. However when I put different audio sources such as a laptop, desktop, TV, or iPod, the mixer produces a very poor quality output that makes the audio sound as if it were recorded in a hall, somewhat echoey, and as if the vocals and certain frequencies were "smothered". I have tried almost every setting and nothing seems to fix the problem, I have even tried all the inputs and outputs, nothing helps. Anyone have any ideas as to what is going on? Thanks in advance.