# Horrible room, but it is what I got.



## scot (Dec 26, 2006)

My home theater is in an L shaped room. Not only that, from the seating position on the right there is a bathroom, stairs to a door to the garage, and in the back stairs up to the rest of the townhouse.

The L is 24' "long" in the area you sit, and 12' wide. Bump out is 6'x12' 

19'
---------------------
|...........y...y......| - Bathroom
|.......................|
-------......x.........||| - Garage - 24' wide
...6'...|...............| 
........|..Z............||||||| - Stairs
........--------------
..............13'

I made bass traps a long time ago (round, JR style bass tube traps, low tuning), stacked them up in the corners and thought they must be doing something good. Ran through with our favorite measurement utility with an ecm8000 and had 15-20db dips at 40, 60, and 120hz. 

Remove all of the bass traps and now I have flat 40 and 120, but now only 8db swinging inbetween. 60hz is still an issue but only about 10db (vastly improved). 

I crawled around to find places where those dips were highest in sound, put the tubes there and... ugh the dips were back. 

I know, super complex room but if anyone has any ideas, I would love to hear them. My speakers are monopole ribbons (nht) 4' from the front wall  and the sub (z) is a tempest based sonotube. 17hz tune, about 6ft tall.

Anyone done a room like this? Right now my measurement looks more like a recording of a 7 on the richter scale than a smooth line.


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## ACGREEN (Feb 23, 2007)

Build a new house? 

Can you put up heavy curtains to make the L a shape a rectangle for when you are watching movies or listening to music?


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## scot (Dec 26, 2006)

No, but it wouldn't work anyway. The heavy curtains would cause one side to be overdamped but only in some frequencies.

I spent about 6 hours moving my speakers and subs, and came up with something passable. In the end I had a big bump up around 50hz, but no big dips. I added some filters into my BFD, and this is what I came up with. I think for an L shaped room that is a REALLY good curve in that space. (I cut it off at 132 because thats where sub changes stop making a difference and everything is on my main speakers.)

I have learned quite a bit about placement of bass absorbing material, and could definitely see a specific difference by moving them around. At one point 6db. That being said, it is not intuitive and requires serious playing. 

My high frequency space still looks like a freakshow. I need to put something on the walls that will absorb some of that but won't affect bass. 500hz+ I actually have a 20db dip at 500hz as well, but think some damping might help with that.

I only do DIY, so no purchased traps please.


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## scot (Dec 26, 2006)

Nothing? Hmm I would have expected something. If anyone is interested I will post up more frequency sweeps. 

BTW, this was using a macbook pro. Honestly the java sound piece is difficult to deal with, bad clicking issues etc. Had to use the alternate sound interface, but once I switched it worked flawlessly. Now my biggest problem for measurement is the airport about 3-4 miles away. If I time it poorly the planes register around 60-70db at 5hz!


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## salvasol (Oct 31, 2006)

My suggestion to get more attention and comments on the graphs .... start a new thread on the REW section :yes:

Is okay here, but I'm sure most will like to see about accoustic treatments :bigsmile:


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## scot (Dec 26, 2006)

Yes, thats the point of posting the graphs here. I don't need help interpreting the graphs. I am looking to see what types of enhancements I can do to the room.

Honestly I have seen so many posts in both locations that begin with "I didn't take measurements first, but everything sounds so much better..." Ugh. That's useless, take everything back out of the room and measure again so we have baseline vs with enhancements.

I am thinking about a resonator to put in part of the room where bass is strongest around certain frequencies (20-30 db jump), corner traps for the front, reflection point absorbers on the ceilings and a few other things. I am not about to go get a 10' tower of 703/mineral wool without seeing a real graph showing the improvement though, and I haven't seen anything yet.

Anyone here played with Helmholtz resonators? 

How about proper corner traps (not absorbers). 

How about difusion techniques?


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