Topic: Optimal Listening Room Shape ??

[kindms]

I had a question and was hoping perhaps one of you might have an answer or opinion etc

Lets say you were building a listening room. Lets say that there are no restrictions for the shape etc. Is there a "perfect" shape for a listening room ? Something that would make it acoustically superior so to speak ?

[Gutbucket]

Irregular. Generally non-parallel walls and different dimentions for each wall to reduce flutter echo and spread out the bass nodes.  A square, cube shaped room sucks.

Here are some ideas-

[Burnt]

Gutbucket where is that first picture from, looks like a very nice room.

[sparkey]

Oddly enough, I just commented a couple of days ago that my playback system was set up in the most acoustically friendly room I've every had any of my systems in.  It's an older house, probably built in the 30's, with the rounded doorway tops.  The top of the rooms are rounded all the way around and it gives it an excellent, spacious sound.  Right now I'm goin' two channel, but can't wait to get my other three speakers hooked up for the surround sound.

Josh

[Gutbucket]

^^^^
The best sounding room I had was the last place I lived, built in 1933.  It was symmetrical with big jalousie windows filling nearly the entire wall behind the listening position that acted as a stellar bass trap.  I also think the plaster-on-lath wall construction, the suspended hardwood floors and 10' ceiling had positive influences.  That place didn't have the arched doors and curved wall to ceiling intersection, but many other homes in the area from the same era do.

Gutbucket where is that first picture from, looks like a very nice room.

Burt,  it's geographically about as far away as you can get from the US. Here's a shot of the outside of that room-


BTW I was obviously kidding with the oval office, but I have heard about some control rooms that are shaped like an ellipse.

[Eigenklang]

I have not been in the oval office yet, but once i played in an elliptical room with a string quartet and in an circle-shaped room with a large orchestra. Both had terrible acoutic qualities for the musicians. At least, we were not used to these strange acoustics. Also I did not get the chance of listening from the normal listener's position...

I have heard an 2 channel setup in a small elliptical room at the high end show in munich some time ago. The sound of this room was like the well known "phaser" effect that we all know, but without the well sounding parts in it.

To make things short: For 2-channel setup I prefer quite normal shaped, but acoustically optimised rooms.
The more furniture you throw in, the better the sound will be. Less furniture means more expensive absorbers, diffusors ect.

For further information, collect pictures of existing good sounding rooms and read a book (or 2) about room acoustics - it is a very interesting, but in practical terms also a very expensive topic.

[Gutbucket]

I have not been in the oval office yet..

"Dude, you should hear those sick Nixon tapes!"

..but once i played in an elliptical room with a string quartet and in an circle-shaped room with a large orchestra. Both had terrible acoutic qualities for the musicians. At least, we were not used to these strange acoustics. Also I did not get the chance of listening from the normal listener's position...

I have heard an 2 channel setup in a small elliptical room at the high end show in munich some time ago. The sound of this room was like the well known "phaser" effect that we all know, but without the well sounding parts in it.

I'm not really suggesting that kindms build a room shaped like the US president's office or the Ford logo.  I'd imagine those rooms would sound pretty wierd for normal uses or for performing.  I'm certainly no acoustics expert, but I belive the application of an elliptical control room is very dependant on where the speakers and listeners are positioned.  I found the example I was thinking of The Garden at Plant Studios that uses some unusual, super wide dispersion monitors.  Here's the a plan view-

I surmize that the ellipse shape as applied here focuses many of the first reflections off the walls toward the brown diffuser at the back of the room, effectively making the room sound larger and more diffuse, but all that would easily scewed up if you moved things around. A very speciallized case.

To make things short: For 2-channel setup I prefer quite normal shaped, but acoustically optimised rooms.
The more furniture you throw in, the better the sound will be. Less furniture means more expensive absorbers, diffusors ect.

For further information, collect pictures of existing good sounding rooms and read a book (or 2) about room acoustics - it is a very interesting, but in practical terms also a very expensive topic.

Completely agreed.  There is alot of great information on-line as well.

[kindms]

I appreciate the responses.

I understand that speaker placement etc is going to effect the room etc. I guess the "irregularity" of the room is paramount.

The thought occurred to me on my way to work the other day and figured one of you guys would have better info etc and I was correct.

[Gutbucket]

Well as Eigenklang mentioned, I think for normal purposes the 'things of life', like furniture, bookcases, shelving, pictures, lamps, busts of Beethoven and the like make for good irregularity that provides diffusion. Those things can mostly fill the roll of the non-parallel walls in fancy purpose-built rooms.

Most people suggest a not-irregular, symmetrical arrangement of the speakers and listening position.   

A rectangular room is a good basic, normal room shape for sound.  Some people like the idea of using the golden-ratio to determine the wall dimensions.. like the Parthenon.  You have to admit the Greeks had some advanced acoustics going on with those amphitheaters.  As for the how the Parthenon sounds?...

[shaggy]

^^^^
The best sounding room I had was the last place I lived, built in 1933.  It was symmetrical with big jalousie windows filling nearly the entire wall behind the listening position that acted as a stellar bass trap.  I also think the plaster-on-lath wall construction, the suspended hardwood floors and 10' ceiling had positive influences.  That place didn't have the arched doors and curved wall to ceiling intersection, but many other homes in the area from the same era do.

Gutbucket where is that first picture from, looks like a very nice room.

Burt,  it's geographically about as far away as you can get from the US. Here's a shot of the outside of that room-


BTW I was obviously kidding with the oval office, but I have heard about some control rooms that are shaped like an ellipse.

Been inside and saw some music in the largest hall.  it is not a very good sounding room for some reason....

[Gutbucket]

^^^^
I've heard that too, ironic, huh?  I watched a PBS special on the Operahouse and the controversy over its construction and how the estranged Architect never entered the building until contacted by renovators 30 years later.  Apparently the interior was not built to his specifications, the design changed completely to save cash, and the sound suffered for it.  The renovation apparently included major acoustical and electronic efforts to correct the shortcomings.

I'd love to see the place in any case.

[shaggy]

It is truly an amazing building but I was dissapointed in the sonic character of the hall.  That said, these small halls here in Tokyo are just awesome, my favorite is this one and despite the traditional rectangular shape, it is an awesome sounding hall.  I think alot had to do with Nagata Acoustics remodelling the hall a few years back:

http://www.suginamikoukaidou.com/guide/hall_l.html

[kindms]

There are several really sweet acoustic venues in upstate NY

The Egg



There are a couple of theaters in the venue. Everything about the main room is irregular. It was an amazing venue but because of the irregularity of the room it sort of gives you a feeling of being unbalanced. It was strange walking around in there. I thought it was just me at first but when I mentioned it to the group I was with several of them described a similar "feeling"

[Gutbucket]

I lived upstate for a while but unfortunately never got to the Egg.  Looks like one of the most improbable buildings ever.  Whenever I see it I try to imagine how anything fits in there.

[Petrus]

Irregularity is good, but the room MUST be symmetrical along the listening axis, otherwise the stereo image suffers. This is often difficult in normal home conditions.

The classical listening/monitoring room is live end/dead end, with the loudspeaker end of the room heavly damped, but the other end quite normal to give the room some life.

If you designing a rectancular room it is easy to make an exel worksheet with the room dimensions and calculate the standing wave upper harmonic frequences and see that they are spread out evenly.

My small* listening room has fairly "soft" walls, floor & ceiling (wood panelling, floating floor) and has angled ceiling falling from about 9' to 7.5' towards the back. The speaker response is quite even and almost straight from 15 Hz to 20 kHz, possibly even higher (I have only CD pink noise, so have not been able to measure past 20 kHz). It also has a dead end in the form of 2 foot deep wall sized storage space filled mostly with clothing behind a heavy curtain behind the speakers.

Monitors: ADAM S3A + Genelec 7071A

4x5m/13x16' floor space.