"My room is far from perfect, my question is , I have excessive bass on the perimeters of the room and the corners , leaving the middle of the room bass light, will bass traps help the cancelation of bass in the center?"
At the risk of sounding like I know what I'm talking about (see my previous comments if you are gullible enough to think this) I am pretty sure you won't affect the "bass light" characteristic of the center of your room. Assuming a rectangular room, the fundamental modal frequency of each dimension of your room will have lowest velocity, therefore highest pressure, at physical boundaries (walls/floor/ceiling)and that freq. will have its highest velocity (therefore LOWEST pressure) at the center of the room. This is true also for top to bottom, which people sometimes forget. What this means is that each of the three primary mode frequencies will have the LEAST volume at the dead center of the room. For a room with dimensions of 10 x 16 x 23.3 (a favorite ratio of acousticians, with good reason) this would be a point 5 feet from the floor, centered between each pair of walls.
If you put a bass trap(s) in the room, they SHOULD be at the point(s) of highest pressure as you said. This will absorb some of the energy of the bass freq. and cause less apparent (and actual) bass at that freq.; however, I don't see any way that cutting the sound pressure at the wall would cause any increase in that pressure/frequency in the center of the room. If anything, it might reduce the level in the center of the room also, since you've just converted some of that energy to heat.
If you draw out your room to scale, then subdivide it into two, three, four, five, and six sections, and do that in all three dimensions, you will define the points of the room that will have peaks/dips at what frequencies. Let's take the 23.3 foot dimension in the example I gave, which would support 24.25 hZ, the lowest frequency this particular room will support. Taking just that one dimension of the room into consideration, you would also have resonances at (keeping math simpler by rounding off) 48,72,96, 120, etc - If the 24 hZ level is minimum at the center of the room (all will be maximum at the walls) then the 2nd harmonic (48 hZ) will have 3 maximum and two minimum level points in that dimension; max at walls and center, min at 5.82 feet from each end wall. The THIRD harmonic of that dimension at 72.7 hZ will have peaks at 1/3 and 2/3 the length, and dips at 1/6, 3/6, and 5/6 of the length, or 3.88 feet from each wall and at center.
If you do this exercize for each dimension of ANY ROOM, you will find that the center of the room SUCKS for ANYTHING! Every resonant frequency the room supports will either be peaked or dipped at the exact center of the room. The only solution I am aware of is don't be in the center of the room!
If you are experiencing nulls in the center of your room, that means they are either the 1st, 3rd, or 5th harmonic of that dimension. To find out which, you could try moving to a point 1/3 the length away from the wall; if you find another peak, then the offending freq. is the 1/3 harmonic. If the peaks come at fifths of the length, then that is the 5th harmonic of that dimension. This gets so complex when you add in 3 dimensions, furniture, people, tangential and oblique modes, that sometimes its easier to just move things until they sound good. F. Alton Everest, in at least one of his books, remarked that for the most part figuring anything beyond axial modes of a room is a waste of time, since the first piece of furniture/equipment you put in the room changes everything anyway. Still, it's good to know what frequencies to EXPECT to have problems with, and which dimensions are responsible for them. The basic formula for finding this out is Frequency = 1130/2L, where L is the length of the room in feet. This will get you the lowest axial mode frequency of the room. Do the same for width and height, then multiply each frequency by 2, 3, 4, 5, 6, throw away any results higher than about 300 hZ, etc, and you have the axial mode response of your room. If you want an easier way to figure this, there is a simple Excel/Lotus spreadsheet I wrote about 10 years ago here -
http://www.prorec.com/prorec/downloads.nsf/category
The file is called roomtune, it's under Other Application. It is a self-extracting archive that includes a wordpad info file, and both Excel and Lotus versions of the spreadsheet.
If you really want to know more about your room, download MODESv2p.xls from this site -
click on Calculation Tools to get to the file. This sheet does all the things I was going to re-write mine to do, probably better. The cool thing (for me, anyway) is that for once I found it BEFORE I went to all the trouble of writing my own... Some things to watch about this sheet - you have to convert your dimensions to inches before you enter them in the yellow boxes. Then, you HAVE TO follow the directions on the first page (1,2,3) or the sheet won't recalc the graphs, and you'll be looking at someone else's room graphs and YOUR mode frequencies. Bummer...
This sheet also has some good basic advice on traps/locations, etc - I use it a lot. Be sure to click on the various tabs at the bottom of the first page in order to see all the views of the information generated.
I hope this answered some of your questions without muddying the water even worse - If not, post back and I'll try again... Steve
I have just recently built a project studio in a 2000 sqr/ft lot. The partition wall between my studio and the shop next (I am in a strip mall ) was said to be 14" wide - staggererd studs 5/8 drywall with insulation. To achieve an STC of 55 we built on accordingly. As it turns out the wall between me and the next door is roughly 8" - not on staggered studs but with insulation. My room has 14" high ceilings and I am recording drums in this room. Now problem is since the partition wall is so thin i cannot get away with recording drums during daylight hours - luckily It is only 800hZ and below coming through and not the whole spectrum. My question is - with bass traps or low end absorbers - can I put these in the room and have the low end energy tuned into heat or absorbed to cut down on the boom in the room and keep the spl from building up and going through the partition wall. There for being able to record during the day.
