[ipooptoomuch]

You have two 10" cubes made out of pure diamond that you use to place your speakers at ear level. You also have an old 30 lb unstable wobbly wooden desk. There are 2 cardboard ups boxes on the desk to place the speakers at ear level. Will there be a difference in sound quality between the two setups with monitors or speakers? When the systems are installed will it make a difference if the diamond or wood "speaker mounts" are placed on carpet, concrete, bathroom tiles, etc.?
 
My setup: M-Audio BX5 D2 monitors from balanced XLRs through an Art Cleanboxpro with a Playstation or M-Audio Audiophile USB as the source.
 
Which of the 3 volume controls on the 3 devices has the cleanest output and how much I should crank each of them to get the best sound quality? (USB, Cleanboxpro, BX5 D2, also the Playstation or windows volume if that counts)

 

[Exediron]

In my experience the only thing you'll notice is that if the speakers are in direct contact with the desk or in contact with a hard object which is itself in direct contact with the desk, you might get vibrations. A bit of foam or carpet under the object would usually be plenty to get rid of that. As for the diamond vs. cardboard box, I wouldn't trust the cardboard boxes with the weight of the speakers, but otherwise I'd expect them to sound at least as good.