# Setting up a surround setup



## omholt (Jun 5, 2007)

Thought I would start a thread as I'm setting up a surround system. The room will be heavily treated. My priority is surround movies, but I would also like it to work well for music in surround. Two channel music isnt a priority here, I've another setup for that.

About the speaker system. I'm waiting for three Geddes Abbey speakers which will be used as fronts. These should arrive in February.
http://gedlee.com/abbey.htm
Geddes Harper will function as surrounds, but might be used some as fronts in the beginning.
http://gedlee.com/Harper.htm
Two Geddes bandbass subs will work as midbasses:
http://gedlee.com/Subs.htm
One Elemental Designs 18" sealed sub will take care of the deepest bass:
http://www.edesignaudio.com/product_info.php?cPath=2_138&products_id=640
Something worth noticing is that the Geddes Abbey and Harper speakers don't have any deep bass at all. That's why I'm using midbasses and they can be placed wherever they perform best in the room. To set up the three subs, I have a Behringer DCX2496 to help me.

In the beginning, till I receive the Abbeys, I will also use a pair of active Adam Classic Column MK3 speakers.

Wish I has a projector, but I've to stick to my 50" Panasonic plasma for now.

First some pictures of the room as it is now. I will get back with dimensions. But as one can see the room has sloping ceilings. And because of the closets built into the room, the height at each end differs. The first thing I need to find out is on which side to place the speakers. Measurements should give me a clue.
My plan is to fill the closets with low density porous material. Should be a nice basstrap.


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## omholt (Jun 5, 2007)

The dimensions of the room are as follows.

- Width: Ca. 3,54 m
- Length: Ca. 5,47 m mesasured from inside of the closet (I assume most of the bass will go through)
- Height outside closet: Ca. 1,69 m
- Height on other short side: Ca. 1,43 m
- Height in the middle (heighest point): Ca. 2,47 m


I tried the speakers in front of the closet. The measurement were a little more uneven at this position.
Started to fill the closet with low density fiberglass. Nothing major changed with the frequency response, but a bit more even.

A question about the fiberglass. I's practical to leave them in their packages. But they are packed quite dense and tightly that way. Would it be better to take them out and into something else so they become more loose? I don't know the density numbers of the fiberglass but this is stuff that is used for isolation, so it should have pretty low density.


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## omholt (Jun 5, 2007)

I got a suggestion of placing the speakers on the long axis of the room in front of the windows. This should cause less problems with the sloping ceiling. I see some disadvantages with this though. It's going to be very unpractical placing the couch, because of the door into the room. I will be more assymetrictral since the closet that eats into the room make the distance to that sidewall closer. And I will not be able to use any diffusors behind listening position, the rear wall needs to be dampened only.

I've applied some measurements with this setup though. I don't know if there's any point in showing unsmoothed measurements at this point. There's an encredible amount of combfiltering now that the room is basically empty (except the fiberglass in the closet).
There are both linear and logarithmic frequency responses and ETCs of each speaker. I will post measurements of another position in my next post to compare.

Measurements:
1. Left speaker linear
2. Left speaker log.

3. Right speaker linear
4. Right speaker log.

5. Left speaker ETC

6. Right speaker ETC


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## omholt (Jun 5, 2007)

Hmmm. I see know that the names of the graphs are not visible. So you can't see which is left and right speaker. Something the moderator should look at?

I have to write which is which.

These measurements are from the speakers seen in the first post. The closet is then the rear wall. I took this measurements before I placed the fiberglass in the closet. The speakers are pulled out from the frontwall quite much. I'm thinking because of the low ceiling height there, that it may be important to get some feeling of spaciousness.

1. Left speaker linear
2. Left speaker log.

3. Right speaker linear
4. Right speaker log.

5. Left speaker ETC

6. Right speaker ETC


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## omholt (Jun 5, 2007)

A way to compare the graphs could be to have two opened windows.

Looking at the upper frequencies there's not much difference, but I would say it measures a little better placing the speakers on the short side of the room. The ETC is in my opinion also better here.
Diffcult to say which is better in the area between 150-400 Hz. My guess is that the cancellation between 200-300 Hz is mainly floor bounce.

Anyway, I think I will settle on placing the speakers on the short side and let the closet side with higher ceiling height be the rear wall. This is also the most practical way and it seems to measure just as good as anything else. I will have to treat the sloping ceiling probably on both sides, but it will also enable me to have some diffusors on back wall and rear sidewalls. Diffusion probably isn't very important for movies, but it might be nice for surround music and to keep the room more lively compared to only absorbing the rear.

The Geddes speakers don't need much absorption on the sidewalls by the way due to the waveguide, controlled dispersion and the fact that they are suppose to be toed in so they cross in front of the listener. They are not made to listen to on-axis (except the center speaker). This means I only have to absorb the opposite sidewall some for each speaker.


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## omholt (Jun 5, 2007)

Let's look at the development with more treatment. First ETC before more treatment.


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## omholt (Jun 5, 2007)

Then I added two absorbents (22 cm) on sidewalls. I simply placed these by guessing the first reflection from the opposite speaker. Will do finetuning later.


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## artur79 (Dec 29, 2011)

What are your thoughts on the closet doors? Will you keep them? Won't a door _and_ diffusors make it hard for bass over a certain frequency to pass through?


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## omholt (Jun 5, 2007)

artur79 said:


> What are your thoughts on the closet doors? Will you keep them? Won't a door _and_ diffusors make it hard for bass over a certain frequency to pass through?


The closet doors are pretty thin, so they should let through the bass. Placing diffusors in front of them is more of a concern. The bass will not go right through the diffusors, but probably around them. I've already seen from measurements that it gave me a small cancellation.

I can avoid this by turning the setup 180 c, but that will give other issues. I bascially have to try different options.


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