Yeah I know . Sorry about that . The others were better for what you were looking to do than the one that works . the home site for the calcs is Alpha Certification . If you are really interested try a search .

As for the ceiling it should act a lot like a diffuser for high freqs . not necessarily a bad thing .

It is really difficult to say for certain what effect the beams will have on the low end . It could be positive or negative . The beams could create nulls or peaks in the low end . It really would be determined by your listening position which effect they would have .

Generally, beams and the like tend to help lower end because of standing wave issues. The rule of thumb is, the more you can breakup standing wave by having irregular patterns in the room, the smaller the standing waves will be anywhere in the room.

If you ever look at a picture of an a-chamber, the walls have hundreds of opposing shapes to break up sound waves.

Think of dropping a large rock in a calm pool at one end.. A large wave will form and bounce off the opposing end of the pool.. If you were to put a number of obstructions at random points in the pool, no waves of any size will reach the other end. Its the same with sound.

Furniture helps too...

So the beams are a good thing?

Well beams by themselves? Maybe, but certainly adding furniture, carpet, etc, all contribute to sound absorbsion and breaking up standing waves.

Picture a 20hz note, which travels something like 55ft per second, hitting a number of beams and partially breaking up and reflecting sound. Some of which get absorbed into couch you are sitting on.

Now picture and empty cement room with nothing in it. The empty room would sound boomy, because that note traveling at 55ft per second would hit the back wall of your 20ft theater room unobstructed, bounce off the front wall reaching your ears twice in less than a second..

Also, the waves would crash into each other causing standing waves or cancellation of sound. Depending were you sit, this can be bad..

If you were in a room with no wall or infinite sound aborbsion you would get the true image of what came from your speakers..

Most people do not have theater rooms like this..

i could be wrong but i thought a 20hz note was like 56 feet long and within that wave the air particals move up and down 20 times per second(cps or hz),never heard of a 20 hz note MOVING 55 ft/sec.
i just read something about this,i'm gonna try to find it again to see if i'm mistaken.

Sound travels at 1130 ft per second . That is how you obtain the first axial in a room by adding the width, height or length by itself . Then divide 1130 by that number giving you your first primary axial . For example a room 20 feet long would give you 20 + 20 = 40, 1130 div by 40 = 28.25 hz wave . This is the freq. of the first bass wave to fit perfectly between two walls in a room 20 ft long .

Trikos knows this . I think he is just trying to simplify things .

Wingnut, I don't know if the beams are going to help or hurt your situation . Trikos is right anything that helps to bust up standing waves is a good thing . But I wonder where they are going to reflect the waves too . That we cannot say with any certaintity . At any rate I doubt that you are going to remove them so again it looks like it is something that you will just have to make the best of .
I for one feel that you could probably get a very true to real sound in this area if you wanted too .

ok,thanks for the lesson.never have been THAT into it,guess if i had stayed in electricity and electronics instead of getting into autos(20 years ago) i would have known that!

Painttoad, sorry to rag on but I didn't mean it like that .
Check out this cool little link .

http://www.indiana.edu/~emusic/etest/acoustics/chapter1_speed.shtml

http://www.indiana.edu/~emusic/etext/acoustics/chapter1_speed.shtml

last one did not work try here .