I know there is a forum for room construction but many here have awesome rooms are in fact design them for other so...

What are the basic design rules? I've heard many, such as:

The rule of 1.618. Room width x 1.618 = Room Depth. Room width / 1.618 = Cieling Height.

The 1/3 rule or screen height x 3 = optimum seating distance.

Or... screen width x 1.5 - 2.0 = optimum seating distance

The "circle of sound". Its a drawing showing the center channel at 90degrees, L/R @ 130 (?) and the surrounds at 30 degrees from this main seating position.

So are any of this fact? If not what are some basic design tips to follow?


Mike

Those are all fairly good basic rules.

As for the "circle of sound", if the center is at 0, you want the main speakers at about 30-40 degrees off of that and the rear speakers typically about 135/225 off center, but it depends a little on the setup, preference, speakers, etc.

Does any doc exist for these baselines?

CEDIA, CES or manufacturer (logical source would be screen and projector companies as well as speaker folk)?


Mike

You may find both of these ITU doc's good reading.

In regards to room ratios, they are not as important as most people think :eek: Now qualifying that statement. Room ratios and room modes are real problems in rooms with high mass surfaces, so if your room is an underground bunker with 6 concrete surfaces, they will be a problem. If however your room is like the vast majority of rooms, with timber frames and drywall, the vast majority of the energy simply escapes so the mode is not a problem.

Hope these thoughts helped.

Cheers

Steve

thanks

Didn't we just have a thread about room ratios...?

Dunno.

Did we? If so point me in that direction.

So far I've learned a 2.0 ratio is bad! (14' x 28')

It can cause LF boost in the 1st and 2nd harmonic. 1st ain't to bad since most subs can't get down and growl that low. Again this is dependant on the room dimensions.

Dunno.

Did we? If so point me in that direction.

So far I've learned a 2.0 ratio is bad! (14' x 28')

It can cause LF boost in the 1st and 2nd harmonic. 1st ain't to bad since most subs can't get down and growl that low. Again this is dependant on the room dimensions.

No it's not, it's dependant on wall density. Remember a 20hZ tone is 17 metres in length, that is why when you stand outside most buildings it is the LF you hear not HF, the bulk of the LF energy escapes the "room" so the reflection, and therefore the mode are significantly reduced.

I wish most people paid as much attention to speaker placement which is critical over obsessing about ratios :confused:

Dunno.

Did we? If so point me in that direction.

So far I've learned a 2.0 ratio is bad! (14' x 28')

It can cause LF boost in the 1st and 2nd harmonic. 1st ain't to bad since most subs can't get down and growl that low. Again this is dependant on the room dimensions.

You know, I spent a few minutes looking and couldn't dig it up. I would dig back in the acoustics threads on the builder forum, lots of great info there. Bottom lin, yes room dimensions matter, but they are a very crude tool that only look at basically one very narrow thing. Certainly its nice to avoid the worst dimensions, but beyond that it's probably better to more fully model the room anyway.

In my experience there are no "good rooms", only a few really bad ones.

Stay away from dimensions that are even multiples of each other. Try to make the room volume at least 1500-2000 cuft.

Other than that, all rooms have plenty problems, and must be treated with broadband acoustic treatments.

The Home Theatre Builder forum is a tome of knowledge about this.

In my experience there are no "good rooms", only a few really bad ones.

Stay away from dimensions that are even multiples of each other. Try to make the room volume at least 1500-2000 cuft.

Other than that, all rooms have plenty problems, and must be treated with broadband acoustic treatments.

The Home Theatre Builder forum is a tome of knowledge about this.

Well said kromp,

actually alot of very bad ones..... take your speakers outside and listen to them free field, that's what is coming out of them, the rest of what you hear is your room

as soon as we radiate energy in a box we get all sorts of issues, look at any high end studio, you will see large rooms, complex geometry, tall ceilings, things virtually no home has, bottom line is all about LF, if you have high mass walls you will have big problems, if you have typical drywall walls the issue is greatly reduced, i can't emphasise enough for you to worry about your speaker placement more than your ratios, a couple of degrees of tilt can fix massive fq response problems.

My 2c

Steve

Standard drywall is the plan using a Dynamat (or similar) material to keep sound in and of course keep sound out. That is what I call a "sealer" or lid.

Another trick of the trade that I was told was to set in the perferred listening postion and have a friend walk along with a mirror (oppostie wall of speaker. ie: Left main walk along right side wall) and when you can fully see the speaker that is your first reflection point.

Again as other have said speaker placement will skew that as well.

Thanks guys and have a great holiday!

I experimented with all the major methods out there in my room (no joke...). Two worked well, but only one was significantly better than the other one. The first was a nearfield type setup, recommended by Ethan Whiner (http://www.realtraps.com/art_room-setup.htm). This setup involves the room the least, but it requires sitting closer to the speakers and it didn't allow me to use the entire room with my particular room dimensions (a great monitor setup for mixing, and sound engineering).

The second is placing the seating position ~1/3rd the room length from the back of the room mixed with the WASP method (http://www.tnt-audio.com/casse/waspe.html) for speaker location. I had Rives Audio design my room and general speaker layout, it ended up that the best seating position and speaker layout were in those areas. I voiced the room myself using the WASP method and I found the same areas as the Wilson dealer (before the dealer came out) sounded the least affected by room boundaries. The areas we found via the WASP method also corresponded exactly to the general vicinity Rives Audio had identified as the best locations as well!

I preferred this second setup because it involved the whole room in the experience. It expanded the soundstage to my room size and made playback seem like a live event compared to a small picture frame...

Check out all the possibilities just to have the experience with all the methods, perhaps you will have a different experience because of room dimensions.

BTW, my room is a rectangle with some irregularities, but the basic dimensions are 18' x 33' x (7.7' to 9' - tray ceiling).