treating room for vintage Infinty dipole speaks

Looking for some recommendations from AKers on room treatments and where you put diffuser panels and frequency control panels?I just removed some entertainment towers(they went upstairs) that were behind my speaks(RSIIb's) and what a bad result!Imaging and sound stage almost is a "mush" now.Thanks for your thoughts.

Randy

I’m very interested in hearing about this as well. I found that panels behind my RS-IIs helped quite a bit. The panels were already installed before I got the RS-IIs and after listening to them, both with and without, I decided that they were gonna stay.

What type of panel do you have,diffuser of frequency(deading) control?

Randy

i get excellent depth of image with nothing but 5' of space and a concrete wall behind my RS1Bs. what are your walls like, randy?

Currently using only ASC tube traps in corners behind woofer cabinets on RS1B's. Have tried many configurations and this current set up is the best to my liking. Nothing behind the mid/tweet panels but window and plaster walls. Any treatment behind the mid/tweets always sounded lifeless to me and others that heard the system.

I made two DIY panels from Owens Corning 703, approximately 5’ X 2’ in size, placed directly behind the speakers. My RS-IIs are placed about 7 feet apart, 3 ½ feet from the back wall, and 2 ½ from the side walls.

Right now, the back wall behind the 2b's is painted drywall, there is about 4' space and 7' apart at center line.I had about the same space before I moved the entertainment unit and the imaging,sound staging was pretty good.Now alot of the presentation favours one speaker mostly?I also have a 50" Plasma TV between the speaks but it was there before.

Randy

You are moving in the right direction. Room tuning is the most important and ignored aspect of sound reproduction. It is ignored because it is difficult and hard to understand for most people. Read the Master Handbook of Acoustics to get an idea how complicated is this. The best tool out there is a software called CARA. CARA is easy to use and it consider virtually everything from the wall material, studs, to furniture and speaker. by model. It is fairly easy to use considering how hard is to accomplish the room tuning by hand and paper.

A bit about the topic...

Room treatment is divided in 2 areas: resonance and reflection. Resonance is for low frequencies which are large enough to resonate to the room. Reflection is for mid and high where sound waves can be considered as rays like a flash light or a laser.

1- Room dimensions. Room dimensions are important because they determine the nature and severity of room modes. Room modes are the resonant frequencies of the room in the low range. There are some golden room dimensions. If your room falls out of the golden ratios then reshaping the room is the best sounding option. The other option are the use of additional bass traps, but is not as effective. Bass traps are used even if the room dimensions are very good. They are placed in any corner regardless of speaker placement or proximity to speakers. For example, 4 bass traps are more effective in the 4 corners than 2 per corner. Also moving the bass traps out of the corner reduces its effectiveness no matter if they are closer to the speakers.

2- First reflections. Any wall, floor, and ceiling surface area that when sound bounces on it can reach the listener directly is a first reflection spot. These are very damaging to mid and high frequency definition. To find them sit on the listening spot and have someone move a mirror on any suspect surface, when you can see any speaker on the mirror mark it as 1st reflection spot. A strong sound absorber panel must be placed in all of them. A 2"x24"x48" of sonex is ok. There are 2 spots on each surface of a rectangular room.

The use of diffusers and additional absorption is to keep a reasonable balance or life to the room. CARA is very helpful on that. Using too much room treatment products can also create a bad sounding room. Diffusors are typically used in the wall behind the listening spot.

Each room is different and what works for one room probably does not for another. This is not like buying speakers, it is more like designing one.

About the Infinity speakers: Some are design to reduce the amount of sound radiated to the sides (the reason for the logo) but the room treatment does not changes because of that. Room treatment is independent of the speakers used. Now speaker placement is, CARA computes the optimal speaker placement.

Good luck!

I've had good results using Carda's room setup guide. See their website.
D

Checked out the Cardas articles. They are over simplistic. They do not even mention 1st reflections, decay time, and other fundamentals. Basically a one fits all solution which probably works in their room, but who knows if it does in yours.

If you are looking for a simple solution, then place a large panel of sonex or auralex where the TV is and one in the side walls half the distance between you and the speakers, and another behind you. That will give you a starting point.

You do not need to spend money on Sonex or Auralex. The sonex panels can be replaced with larger canvas paintings with no glass or any other stretched heavy fabric. The diffusors can be replaced with bookshelfs fully filled with anything. Fabric or leather furniture help as bass traps. Rugs works for the floor as well as on the walls but cannot be flush onto the wall, there should be a space of 1~2" behind.

Can you post a photo of the room?

In my room I have Auralex mini-diffusors and 12"x12" tiles in my ceiling. The entire back wall is a gigantic bass trap made of three 4x8 1/4" panels with foam insulation in the 2" cavity behind them. On the center of the back wall a large canvas acrylic painting. The front corners have 8 auralex bass traps stacked to the ceiling. The side walls have one small 2" x 24" x 48" sonex panels. The floor have a rug on top of the carpet. There is a large bookshelf filled with LPs, CDs and books, and the equipment rack. There is no glass in the room. The only window is covered with a triple layer of draperies, mainly to darken the room.

I place mine about 5-1/2 feet forward from the back wall. The wall is cement-and-soft-plaster over brick, with a "frame" of pillars in the corners and a similar extended "beam" across the top. In the recess thus created are shelves on the top part of it, and a large plasma screen in the middle. There are a variety of objects on the shelves, making the whole set up a bit of a diffractor/diffuser, except for the reflective plasma screen, but that is several inches forward from the wall, with an empty space behind it. Below the plasma screen are racks with audio gear on them, also diffractive. The whole creates a mix of reflection, diffraction and absorption. For whatever lucky reason, it sounds GREAT that way. I've toyed with removing some of the shelves and rearranging things, draping blankets over the plasma screen, pulling down the projector screen (which drops in front of the shelves and TV screen), etc... but nothing noticeably improves the way it is, so I just leave it that way.

For esthetic reasons, I don't have bass traps in those corners, but it doesn't seem to matter. The room, while not very wide, is quite long (nearly 30 feet), so it handles bass (which is primarily limited by the longest dimension of the room) quite well.

There are effectively bass traps at the other end of the room, and various other "treatments" on the side walls of the room, but they don't look like it. I mounted carved wooden decorative panels over cloth-covered foam, so they look like artwork but are also functional as sonic treatments, but they are only to take a little edge off of a slightly lively room. I'm lucky to have side door openings at two major reflection points, so that is completely not an issue. The panels do the rest well; the room is not quite as dead as the costliest listening rooms I've been in, but I like it that way it is now.

I've seen another RS II owner put up large panels (about 4' x 7') several feet behind the speakers, when they were well out in a very large room. I don't remember what the panel material was (this was years ago, before I know enough to look), but I think they were simply a heavy cloth or felt material stretched on a frame(?). I believe they were a commercial product, bought through an audio dealer. This was about twenty years ago.

Thankyou for the responses.Now I've got some imput for what has worked for others,which can save a fellow alot of time searching websites and there is alot!I just couldn't believe the change in performance(bad) when I removed the 2 entertainment towers that were behind the speaks!I need to diffuse there with something to get the imaging back plus some bass traps(corners) and deading on the sidewalls, ceiling in front of speaks?My room is 18ftx25ft,drywall ceiling,8' high but drops to 7' for about a 4' stretch to cover forced air ducting,drywall walls,laminite flooring over concrete(basement rec. room).Yes, it is very bright with echos and I have away to go to tune it up!

Thanks,

Randy

AngelRa, I'll try to post a pic but my camera has been having problems.

Randy

Room front wall, front left corner, and ceiling:

Under projection screen: Sonex panels covered with black drapery.
Behind the light on the corner: Auralex bass traps
Ceiling: Auralex small tiles and diffusors.

Forgot to mention, the speakers are not in the listening spot. The spot is marked on the carpet with tape (not shown). The problem is that it is quite in the middle of the way. So they stay away and close to the walls. The equipment rack is far enough from the wall so I can walk behind it.

Im runing RS-I mine sound great any way i turn them!! Angelra what dipole infinitys are you running? I dont see any infiitys.

I currently do not have any Infinitys.

another approach instead of massive room modifications, is to tackle this at the source. go monopole instead of diapole, attach 1/2" felt to the back of the emim's. they will still 'breathe', but will greatly attenuate the rear output.

it will also give the emim's some suspension, and help remove resonances.

I also in the winter use plants behind and beside the speakers with great success.

just a thought....

bharper said:

another approach instead of massive room modifications, is to tackle this at the source. go monopole instead of diapole, attach 1/2" felt to the back of the emim's. they will still 'breathe', but will greatly attenuate the rear output.

it will also give the emim's some suspension, and help remove resonances.

I also in the winter use plants behind and beside the speakers with great success.

just a thought....

Click to expand...

I think this idea have good merits but with a modification. Place the sound absorbing material with a gap of about 1' or 2' (feet) from the back of the speaker so it gives a chance for the "Infinity" cancellation to work.

Still, there is no way around room acoustics no matter which speakers or radiation pattern.

The Infinity speakers are design to suppress sound radiating to the sides. Sound is radiated to the front and the back. When the back sound meets the front sound cancellation happens. The boxes are shaped to guide the front and rear sound into a collision at the small side of the enclosure or panel. The resulting radiation pattern, if it could be seen, is shaped like the infinity symbol thus the name and logo for the company.

How do that changes room acoustics, it makes it a bit easier. With the side sound radiation slightly reduced the side primary reflection absorption is more effective thus making much more clear sound.