Ive been thinking about options with some diffusor placement. my back wall is easier to work with, but how do you "test" the right spot on the ceiling? i have also been considering the diffusion/deflector panels too. but again how do i determine where to put something when i cant place it there and walk away to hear the difference? is there an equation to tell me the best place?

as for my back wall, what is more important if ive got proper bass trapping, absorption or diffusion?



>slightly off topic but is a treated open space with the panels like the Diffusive Sound Tile Reflector sold by Auralex better than nothing? they are far more affordable than most real diffusors, and more realistic for none pro use to enthusiast such as me...and yet i dont want to buy snake oil either.

DST-R Diffusive Sound Tile Reflector in question:

IMHO,the DSTR-R will be effective at breaking up flutter echo,but will not provide the full benifits,and spacious effect of a QRD or sky line diffuser.

At only one inch thick I can't imagine that "diffusor" will do anything useful at all.

--Ethan

so then would they still be better than nothing to an untreated space, audiofreek?

and with that in consideration, would the rear wall be a good place for this or just absorption?

and yet the unknown ceiling question....

Your money would be better spent on absorption.Unless those panels are practically free,I wouldn't bother with them.You can construct diffusers if your handy with a table saw.

almost free was about right. i got 36sq/ft for 25$ from a local music store going out of buisness. now to decide how to place them for the most results, and im sure the placement is now more important for any noticeable result considering Ethans vote of no-confidence. hopefully they will have more than just a decorative effect. so, if i could just figure out the formula to place the deflector(so called diffusor tiles) i would be set. i just cant seem to wrap my brain around how to place them on the ceiling to listen to the results. am i over thiking this? should i just put them on the back wall and over the listening spot and be done? it seems nothing that simple is ever really correct though...thoughts? when someone makes a heavy DIY ceiling mount diffusor they dont have the luxury to test it in place, right? whats the method to this?

also, should i bother with the back wall at all with these?

as far as the rest ive constructed and hung 5 new 4" thick reflective corner basstraps out of 705, and covered about 60% of the rest of my corners in the room, and will cover the rest this weekend with both 2" and 4" 703 traps. hopefully by the end of next weekend ill be finished making the rest of the 703 traps and have the rest of my corners and reflection points covered. i cant say enough about how good it already sounds. im also rather proud now to have constructed all this myself, and its really mind-blowing to hear the difference and im not done! thanks so much to Ethan for all the work you have done over the yrs and subsequent info thats available to all of us.



thanks again
Jim

My best suggestion is to see if you can turn those around for a profit. Could you get $100 for the lot? Then use the money to buy more absorption.

--Ethan

interesting idea, Ethan.

....so I guess my only question on the matter is can I have to much absorbtion on my back wall? im becoming afraid of over deadoning my room, this has been a slight fear all along.

How much is to much?

it depend of your room size, furniture and absorption material. You can use the RT-60 formula, but it is more for very large room. But it will work to have an idea of what would be "around the target"

thanks frank! so how do these values the calculator gave me transform to how much is to much absorbtion?? it gave me:
Estimated Probable RT60 value of this room is .72 seconds
Probable best case RT60 value of this room is 0.5831999999999999 seconds
Probable worst case RT60 value of this room is 0.8568 seconds

sorry for my ignorance, but how do i apply this?

FWIW, RT60 Acoustic Calculator

that is only simple calculation:
RT60 =.049V/Sa

V = volume of the room
S = Total surface of the room
A= absorption coeficient in sabin

To know the SA value, you multiplie surface with is absortive coeficient. You can find chart of those, like drywall have an absorbtive coeficient of .05. So if you have 800 square foot of drywall, 800 X .05 = 40 sabin.
then you go with window if there is big one, if not, discart it, count it as drywall. the coeficient is .04.
If you have carpet or heavy drap, count it.

So you will have your RT-60, calculated the right way. Then you must select a target. The target depend of the size and the application. When you have the target, you can calculated how much absorption you need to lower the RT-60 to a better level.

take the 500hz absoption coeficient when you look it in a chart.