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.
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
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.
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.
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.