[michaelv]

Hi,
  I have 8 foam bass trap to put in all four conners of my listening room ( 12" x 12" x 2')   The room is 8' height from floor to ceiling.

  So, i plan to use 2 foams (4 ft tall) per conner. My question is whether i shoud put 2 foams together and place:
   1> on the floor
   2> hang both half way of the floor ( 2 feet from the ground)
   3> hang both against to the joint where celing and wall meet.

    Or should i put all 4 foams from floor to ceiling?

    Any idea, suggestions would be greatly appreciated as i'm new to this topic.

thanks very much.

[ctviggen]

I would put both foams together (thicker is better).  After that, I don't think it makes too much of a difference whether they're off the floor or not.  If I had time, I could definitively answer, as I have two Realtraps in my corners on stands.  I can put them on the floor, perform measurments, then put them up halfway and remeasure.  I can do this, but it'll take a while (I have the next three weekends booked).

[Audio-Enthusiast]

Square room is the worst for Resonance.  Lets see... a 12'x12' room will yeild a resonance at the following freequancies:

Length and Width both will have
F1  47Hz x2
F2  94Hz x2
F3 141Hz x2
F4 188Hz x2
F5 235Hz x2
F6 282Hz x2
F7 230Hz x2

8' high Ceiling will produce
F1 71Hz
F2 142Hz
F3 213Hz
F4 284Hz
F5 355Hz

Notice that width and lenght both produce the same resonance that combine and pill up and will create huge peak in respone at this freequencies.  Also when you compair the modes with you ceiling you will get an even bigger peak at 142Hz and 284Hz.
 

You probobly know this but this room needs alot of absorption to pick up all of these peaks.  Especially at the 142Hz and 284Hz.  As fare as where to locate the absorption, I would start with at mid-point, then 1/4 points then 1/8th point.  The thicker the better and oh ya, leaving a space behind the absorption panel and the wall is more efficient and will also increase base absorption.  Hope this helps.l

If at all possible, try using another room for your system...  Good Luck

[Audio-Enthusiast]

OPPss you said you had base traps....

Silly me, I though you mean locating foam.

If you already have them, I would locate 1 in each corner at midway between the floor and the ceiling.  As for the remaining 4, if possible suspend them at the wall, ceiling intersection at midway between walls.  This should at lease reduce the amplification of base being generated by your room (unsually in corners).  Unfortunatelly it will not stop the freequency peaks generated by then room itself.  Square rooms are hard to deal with.  

If you would please try taking measurment and make a responce graph before and after your installation.  It would be great for everyone if you would report back to the circle with your results.  If you have a bit of time, maybe experiment with location and take more measurment.  Moving the traps and making graphs will enable you to get the best results for you room.  If any room needs a little TLC, this one does.  Your effort will be well rewarded.

Cheers

[michaelv]

Thanks all.

I actually put 2 foams together in each corner of the room. THen, i put 2 blocking foam 2"x2" (each has 3' tall) on top of each foam. This create a bass trap from floor to ceiling. It helps a lot , the bass is much tighter. I will acquire more foams for ceiling and wall joint  to further absorbtion.

My room actually is 12'x14' ...but i  think it won't make much difference with 12'x12'

By the way, how do i measure the room? which tooL? Please excuse me for this question as i'm new to acoustic stuffs.
thanks again.

[ctviggen]

One tool is ETF.  http://www.acoustisoft.com/  You do need a microphone.  However, the Radio Shack meter is supposedly fine for low frequency tests.