3
The air contained within the room is the link
between the output of the loudspeaker and
your ear. How air behaves is dependent upon
the attributes or character of the room. It
follows that a better understanding of basic
acoustics and what facets cause the most
influence in the room will assist in making
decisions about the way in which the room
and subsequently the system can be improved.
Room types fall between two extremes. A
room can be “dead” on the one hand (full of
highly energy absorbent materials and
complex diffusing structures) or very “lively”
on the other (few reflective surfaces and a
high proportion of very reflective, hard, non
absorbent surfaces). As so often is the case, a
balance of materials is commonly preferable
to one extreme or the other. The correct
balance is the goal for the end user.
Room attributes which can be
easily changed
The contents of the room impact greatly upon
its overall acoustic character. As you would
expect, hard surfaces like glass and concrete
tend to reflect a broad band of acoustic
energy. Complimentary materials that are soft
and thick in section such as heavy natural
fibre curtains will tend to absorb a broad band
of frequencies.
What are Standing waves?
Sound waves reflecting between two parallel
walls set up resonance modes when one half,
or a whole multiple of one-half, the
wavelength of the sound wave is equal to
the distance between the walls.
These resonance modes are referred to as
“standing waves”. In loudspeakers with
parallel walls these waves will cause
distortions. The standing waves in your room
will distort the frequency response of your
system sympathetically boosting certain
frequencies.
If a certain standing wave frequency is
acoustically isolated from its modal
neighbours, its effect is more likely to be
audible and problematic. This can
compromise the accuracy of any loudspeaker.
Middle and High Frequency
Room Characteristics
The middle and high frequencies are affected
more by room contents rather than room
shape. The surfaces and how they reflect,
absorb or diffuse the acoustic energy will tend
to describe the “sound” of a room. Like all
energy, acoustic energy cannot be destroyed; it
can only be converted into something else or
reflected. The shape of the surface will
determine how it is reflected and the material
will determine whether it is absorbed. All
rooms have a particular sound, and to
appreciate what influences are present in your
room you should be aware of how the objects
in your room will respond to sound.
Sound waves behave in the same way as light
waves or "rays" and so imagine the driver to
be a floodlight.
Reflection: acoustic energy is not converted
but reflected in an orderly, predictable
fashion.
Diffusion: acoustic energy is dispersed in a
random and or disordered fashion.
Absorption: acoustic energy is converted
into kinetic energy or heat. All or a majority of
the sound energy is "soaked up" or disposed
of by the object surface or room boundary.
Bi / Tri Amping
The power that is delivered to your
loudspeakers will have a direct effect upon the
sound of your loudspeakers. You should
select the best that you can afford. Separating
the systems will deliver benefits that can easily
be detected. We would not recommend using
different amplifiers on different drivers.
Bi / Tri Wiring
Improvements can be heard through
separating the energy from each filter in the
crossover. Cables vary in construction but a
good quality cable should be low in
impedance, inductance and capacitance. Do
not use cables, which act as additional
crossover components. Experimentation is
crucial in this situation and a cable that works
well in one situation / room / with a given
amplifier, may not always perform as well
when one of these variables are changed.
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