11
Room Acoustics
Listening your Teresonic speakers in a properly set-up room can be a startling experience.
very room has its own distinctive acoustics, which influences the way we experience the sound from a
speaker. In fact, it's a matter of how the room accommodates the sound and then dissipates it. You
can influence the acoustics of your listening room in various ways. Some simple and relatively
inexpensive adjustments can lead to superb results.
The great majority of listening rooms are rectangular, with parallel surfaces made of hard materials that are
acoustically reflective and can produce standing waves, flutter echo, and unwanted reflections that need to be
eliminated. These large areas are the predominant factors in the overall room acoustics, although the other
items in the room such as furnishings, carpeting, wall hangings, doorways etc. will also play a role. Here are
some recommendations.
Improve the sound stage and image depth
Reflected sound waves that reach the listener within 10-20 milliseconds of the direct signal from the
loudspeaker are sometimes called “early reflections” that can reduce the subjective quality of reproduced sound.
When a reflected sound reaches the listener more than 40 milliseconds later than the direct sound, the reflection
is heard as a discrete echo. This is a desired effect that helps our brain to interpret spaciousness of the room as
any musical performance is heard in some room – jazz club, concert hall… However, if the reflected sound
arrives within around 10-20 milliseconds, the ear/brain system tends to integrate the two sounds so that only
one sound is heard. “Early reflections” in the listening room will tend to obscure the ambient information in
the recording (that portrays the original recording site), leading to a loss of dimensionality and spaciousness.
Secondary arrivals within the first 10 milliseconds are especially problematic, becoming less troublesome as the
arrival time gets to 20 milliseconds or so.
How to deal with these unwanted reflections? When arranging furnishings in your listening room,
remember that reflective objects should not be within a six (6) foot radius of either the speaker or
listener to avoid “early reflections.” If you wish to achieve an even more spacious sound stage, it may
be useful to place a sonically absorbent material on the side and rear walls near the speakers. This can
be particularly effective at the points where the sound wave is directly reflected to the listening
position (a mirror can be used to determine these points). As the distance to the wall becomes
smaller, the suppression of these reflections becomes more important.
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