Axiom Home Page Forums General Discussion Home Theater Room Shapes

In all the reading I have done over the past few weeks I notice that at least 99% of theaters are arranged with the theater wall firing the long way into the room. Resulting in a narrow theater relative to its width. I am not totally sure why this is. I have a few hunches:

Pros:
1)Better viewing positions in more seats for a real theater.
2)Allows one to sit far enough back from the screen without being against the back wall.
3)Minimizes reflections from the backwall.

Cons:
1)More sidewall reflections due to narrow room possibly reducing wide soundstage.
2)Bass accumulating in the narrow ends of the room. (not sure if its good or bad)


Anyone else have any input as to the benefits of each?

My room is 23' wide and 18' deep. I think the wide room allows a much wider sound image by minimizing the crossed reflections.

Interesting question. I have wondered about this before too.

All of your points are spot on in both options.

I think most home theater rooms are not large enough to have more than one row of seats if they use their shorter wall dimension as front to back. I have seen some larger rooms that do have enough room, and they usually can do 5 or 6 seats wide with 2 rows.

I agree with you that not wanting seats along the back wall for better sound is also a big one.

alan,
I was under the impression that, for example, hearing the reflection of the right front speaker off of the left wall, reaches your left ear, confusing the Left-Right separation.

In other words, you are hearing the right speaker on your left when the left wall is close. (assuming no treatments)

By the way the image produced in my room by these M60's is absolutely incredible. They are about 10 feet apart and I sit about 11 feet away. The sidewalls are about 6.5 feet away from each speaker. They are toed in about 2 degrees each.

Ok... this is off topic but I had to point out that your screen name is great! Nice photos on your site as well.

Ron

I have to differ with Alan on this one, my experience since I've incorporated bass traps and acoustic panels using Owens Corning 703 have GREATLY improved the sound/imaging of what I used to think was unbelievable with no absorption with my Axioms.

First Reflections can reduce clarity and imaging of your music source. This is true for floor/ceiling/wall locations of first reflections arriving at your ears after the direct path. When a direct sound is accompanied by an echo that arrives within 20 milliseconds or less, the ear is unable to distinguish the echo as a separate sound source. These reflections obscure fine detail and make it difficult to pinpoint the source of the sound or musical instrument.

The goal should be to create an RFZ (reflection free zone) by treating those first reflection points and improving clarity, imaging. Another benefit of creating RFZ's, is the reduction of "comb filtering". Comb filtering is a result of a source and it's reflections combine in the air. The result is some freq's will be boosted, while others will be reduced based on the different arrival times.

This information holds true for BOTH recording studios and home theater environments, which is opposite of what many will tell you. Just my 2cents.

Here is a graph that shows how much improved the freq response can be in the mid/high freq areas with/without first reflection panels.

Dave, the point Alan makes is also a basic one in the acoustic design of concert halls. A relatively long and narrow hall allows for early reflections to reach the listeners and improves the sense of spaciousness and the general impression of the sound quality of the hall. Many halls constructed a century or more ago had this configuration, although the specific scientific basis for the acoustical benefits wasn't known at that time. Some modern halls that failed to follow this practice have relatively low audience friendliness and in some cases special relecting panels have been added to improve the proportion of early reflections reaching the listeners.

Dave,

By the way, I LOVE your 280Z. I owned an 81 280ZX in the same color as your. I really wish I still had that car, but I was dumb and young at the time, and didn't realize what I had.

Thanks guys. This is a good discussion. I have a feeling that for ultra precise sound location, you want to minimize reflections. For ambience and large area coverage, you want sound reflections. It probably boils down to a matter of preference or expectations. I sat down and listened to Sting's "Soul Cages" and the very first track, right at the beginning, when the classical guitar plays a few notes, they sound like they are entirely coming from the left wall of my room at about the 10 o'clock position. I actually turned my head and expected to see a guitar there. I have no wall treatments for reflections yet. There is a box of 703 fiberglass in one corner of the room but it is not on the walls yet.

Not sure why we are disagreeing about reflections. As far as I know we want to maintain reflections of the side wall but tone down the reflections directly into your ear, which can muck up imaging. You don't want to make the *whole* wall absorbent, just get *some* absorbtion into the first reflection points and maybe some of the normal listening room junk to add diffraction as well...

... or something like that.