AudioControl Richter Scale Series III, Руководство для удовольствия владельца

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Owner’s Enjoyment Manual
TM
Whether a surface is absorptive or reflective will vary
greatly with frequency also. A suspended ceiling or a win-
dow will have great affects on higher frequency, but they are
almost completely transparent to the lower bass frequencies.
As a general rule; the more mass in a surface, the better it will
reflect low frequencies.
For our purposes, we are only concerned with those
reflective waves that can product energy peaks and dips in
the perceived frequency response of the sound system in the
room.
Remember, that despite what you may have read or have
been told elsewhere...All rooms are bad in some way. All
rooms have audio compromises.
Room Modes and Wavelengths
Room resonances (or standing waves / modes) are one of
the most significant problems affecting perceived sound
quality and loudspeaker spectral presentation. These reso-
nances are caused by reflected energy bouncing around the
room from the various surfaces (walls, floor, ceiling). Every
room will have length, width and height standing wave
modes. The question we need to answer is - How bad and
where will the problems produced by these reflections be?
Let’s Do A Little Math
No groaning please, it’s just simple division.
f = Speed of sound ÷ (2 x Length)
‘f’ is the standing wave mode frequency
1130 feet per second is the speed of sound (at room tem-
perature)
For example, if the room is 15 feet long, the math is:
f = 1130 ÷ (2 x 15)
f = 37.66 Hz
So the primary resonance frequency (standing wave mode)
along the length of the room will be at 37.66 Hz. There will
also be additional modes at multiples of this frequency
(75.32, 112.98, 150.64 Hz). Where a room causes real problems
is when the dimensions of the room (height, length, width)
are even multiples of each other. This causes standing wave
modes in several directions to occur at the same frequencies.
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