Wilson Electronics MAXX 2 Series, Руководство пользователя, Страница: 14 / 83

requires a custom-designed bass trap system.
Low frequency standing waves can be particularly troublesome in rooms constructed
of concrete or brick. These materials trap the bass in the room unless it is allowed to leak
out of the room through windows and doors.
In general, placement of the speaker in a corner will excite the maximal number of
standing waves in a room and is to be avoided for most direct radiator, full-range loudspeak-
er systems. Some benefit is achieved by placing the stereo pair of loudspeakers slightly
asymmetrically in the listening room. This is so the standing waves caused by the distance
between one speaker and its adjacent walls and floors are not the same as the standing wave
frequencies excited by the dimensions in the other channel.
C o m b F i l t e r E f f e c t
The comb filter effect is a special type of standing wave noticeable primarily at higher
frequencies and shorter wavelengths.
Acoustical comb filtering occurs when sound from a single source, such as a loud-
speaker, is directed toward a microphone or listener from a distance. The first sound to
reach the microphone is the direct sound, followed by a delayed, reflected sound. At certain
frequencies, cancellation occurs because the reflected sound lags in phase relative to the
direct sound. This cancellation is most apparent where the two frequencies are 180 degrees
out of phase. Further, there is augmentation at other frequencies where the direct and the
reflected sounds arrive in phase. Because it is a function of wavelength, the comb filter
effect will notch out portions of the audio spectrum at regular, octave-spaced intervals.
Subjectively, comb filter effect evidences itself as follows:
• Added roughness to the sound
• Reduction of harmonic richness
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