Q. What can I do to improve the sound of my room?

A. The room containing your sound system, whether it is a dedicated listening room or part of your living area, will have an effect on the sound you hear. Proper speaker placement (click HERE for Speaker Placement Information) is the first factor to address in optimizing the performance of your system for your room, but there several other steps that can be taken to improve the sound of your room.

Reducing Unwanted Reflections

Sound from your speakers is radiated toward the listener and out into the room. The sound that reaches the walls and other objects in your room is reflected off of those surfaces and some of that energy is redirected toward the listener. Reducing these reflections is important because the initial sound coming from the speaker needs to be distinctly separated in time from the secondary sound of wall reflections. If reflections are heard too quickly after the primary sound your brain tends to interpret them as part of the initial sound, causing the perceived timbre to be altered and the spatial characteristics to be confused. The side walls between the speaker and the listener, the surfaces behind the speaker, the floor and ceiling, the surfaces behind the listener, and objects in the room, are all potential sources of unwanted reflection..

Wall and floor treatment
By placing the speakers well away from walls, these unwanted reflections can be reduced, but if this is not possible, reflections can also be reduced by additional means. An absorbing material can be placed on the side walls between the speakers and the listener, behind the speakers, or behind the listener to remove the reflected sound before it reaches the listener. Absorbing materials can be anything from a natural fiber wall hanging or drapery to specially made acoustic panels. To reduce floor reflections, a heavy rug placed in front of the speakers will help absorb reflections directed towards the floor.

Diffusion
Reflections can also be diffused, or scattered, by irregular surfaces. A bookshelf with books arranged so that their spines are sticking out at different distances can help to scatter the reflections into less problematic reflections. A diffusion device can placed behind the speakers, to the sides of the speaker, and behind the listener. Folding, slatted doors built into the wall or free-standing slatted panels can be used. Generally, absorption will do a better job of reducing unwanted reflections, however diffusion can add to the spaciousness of the sound in some instances.

Glass
Glass in windows and doors is highly reflective, and improvement can be made by covering the glass with curtains to reduce the reflection. Natural fiber fabrics for the curtains absorb sounds and will do a much better job than synthetic materials. Even blinds can help, as they act as a diffuser, scattering the reflections.

Furniture
Objects placed near the loudspeaker, such as a coffee table, end tables, and equipment racks can be a source of unwanted reflection. Move them as far away from the speakers as is practical for you room. Especially resist the temptation to place the equipment rack between the speakers. If it must be along the back wall, move the rack as close to the wall as possible, and the speakers out away from the back wall.

Changing the location of your listening seat

Sound waves from the speakers bounce from surface to surface and can interact with each other to cause sonic problems by reducing some frequencies and increasing others. This is especially noticeable in the amount of bass that you hear and feel. Although seating midway between the two speakers is usually the best lateral listening position, experiment with how far you are seated from the front of the speaker. You will want to get the best balance between good imaging and good frequency response. Avoid sitting against the rear wall.

The Room

You may have a choice of rooms when it comes to setting up your sound system. If so, there are some characteristics to look for in selecting a room best designed to offer good sound.

Rigid, strong surfaces: Sound pressure is created from the speaker's output and can cause floors, walls, and ceilings to vibrate. These vibrations will cause the surfaces to resonate, producing energy of their own and coloring the sound. Choose a room with rigid surfaces, preferably with concrete subflooring, a solid rather than dropped ceiling, and reinforced, thick walls.

A stable floor underneath the speakers also prevents the speakers from rocking back and forth in reaction to the motion of the drivers. This motion can reduce clarity. THIEL speakers are provided with stabilizer pins to further reduce this effect.

Shape: The more a room approaches a cube (height, length, and width being equal) the more problematic it will be sonically. Ideally, the room should be proportioned so the room width is 1.6 times the height and the room length is 2.5 times the room height. For example, a typical room with an 8 foot ceiling would ideally have width of just under 13 feet and a length of 20 feet. These proportions help avoid sonic problems with unwanted reverberation, and the canceling or reinforcement of certain frequencies. Choose a room that comes closest to these proportions. If you also have the choice, select a room with a slanted ceiling which helps avoid parallel surfaces.

The advice given here is to help you improve the sound of your system. We realize that in the real world, compromises may have to be made so that the sound system can co-exist with the rest of the household. But the lack of an ideal room or less than optimum speaker placement should not discourage you from owning a high quality sound system. Good equipment will still deliver better sound, regardless of the circumstances, than average components. 90 percent of excellent is still better than 100 percent of mediocre.