suspending monitors from the ceiling

And here was I thinking that for a speaker to work correctly (i.e. as designed) and at optimal efficiency, the cabinet had to be 100% rock solid.

-i.e. NO MOVEMENT WHATSOEVER !

Any movement in the cabinet results in degraded sound.

I’m with @erik_squires on this one

One experiment a friend tried that supports this...

- he has monitors on a stand that rests on carpet.

- So we tried placing 15lb weights on top of the monitors

- the sound improved greatly - i.e. once the cabinets stopped being moved by the drivers

Adding heavy weight to the top of a speaker is a very affordable way to improve things, but it gets expensive if you want to make it "pretty" :-)

Regards - Steve

WillieW   

To look good and to sound good at a good price.

Wonka's experiment is not the only one.  It's pure and simple physics. 

Of course, a lot of things come into play.  The location of the driver, the volume, the mass of the speaker, and the location of the driver relative to the stand.  Tall, skinny, lightweight speakers with drivers waaaay up high are going to have more of a problem than super heavy, and inert speakers with big woofers next to the floor.

I have seen Dr. Floyd Toole Revel Salon 2 floor standing speakers hung from his ceiling, I kidd you not. 
N.B.  He is the author of Sound Reproduction Loudspeakers and Room. 

Proper positioning may take some precise and pia experimentation.