ceiling acoustic treatment

Just moved my system into a new room that I can experiment with acoustic treatments.

I'm using Owens Corning 703 for sound absorption.

Has anyone experimented with leaving space between the panel and ceiling? If so what was the sound difference?
How much space did you leave between panel and ceiling?
Or should I just install the panels flush?
Your ceiling looks taller than average. I would suggest you have little to gain with a ceiling treatment. What part of the presentation do you wish to improve? I would experiment more with the speaker to listener triangle, and speaker to wall placement and see what happens.
i am in the process of doing exactly what you are . from al the pictures i have seen on google images of treated rooms and studios they are hanging down away from the wall . I am only going to hang mine down around 4 inches . i have 92 inch ceilings though .I do not have a hanging method yet but you could devise a way to start long and see how that sounds . You could always go shorter by cutting them down some at a time. I may use a small chain material from home depot . that way they would be adjustable . I see them hanging at a angle alot too.
From the photos, I would suggest first working on side wall reflections before worrying about the ceiling. I have a cathedral ceiling and did eventually put 6 2x4 panels up there of Owens 705 with Ready Bags from Ready Acoustics Co. I did angle them like louvers. They are about 18" from the crest of the ceiling. The result was less ringing, clearer trebles, less stridency in female vocals. I think in general that putting a panel straight on a wall will only limit higher frequencies, but putting one several inches from the wall or ceiling will help trap lower frequencies as well.
Thanks everyone and sorry for the confusion, but my current system pics are before the recent move into my basement. Basement room is 18'x33'x10 ceilings. I'll update system pics when I get a little farther along

I'm already experimenting with panels on side walls.

I'm just curious what the acoustic difference is for spacing the ceiling panels away from the surface.
I went a different route - take a look at my system for more information. The approach I used works extremely well, and looks better too - IMO

Good listening

I think......no need space between the ceiling & panels. But sound quality greatly depends on the the effectiveness of the panels. I am not sure about your panels. But i know a manufacturer, they provide very good looking & effective acoustic panels at a very low price. In the next before making a decision you can visit them first(http://www.acousticmanufacturer.com/Noise-Barrier-on-Temporary-Fence-for-Construction-Site.html). Thank you.