So this is an oversimplification, but for just an axial mode at 9 foot height:
freq = (1130 ft/sec)/9 ft x 2 runs (one up, one down) = 63 hz for a 9 ft ceiling
So look for multiples of 63 such as 126, 189, and even 31.5 for dips or peaks. And then look at all the other room modes and see where they may overlap.
Axial Modes
The simplest path is the round trip between two opposing surfaces in the room. We can calculate the fundamental frequency for this effect using the formula:
Where F = frequency, W = wavelength, and c = the speed of sound.
If we want to calculate the effect of an 8 foot ceiling, the wavelength is 2H or 16 ft. (Remember, it's a round trip.)
The speed of sound is 1130 ft/second, so the fundamental of enhanced frequencies is 70hz.
Try Bob Gold's calculator, and then open a beer:
http://www.bobgolds.com/Mode/RoomModes.htm