ART XL 231 Dual 31 Band, 1/3 Octave Extended, Long Throw, Professional Equalizer
12
APPLICATION NOTES
Graphic equalizers may be used wherever modification of the frequency contour of a
sound system is needed. A graphic equalizer is a solution to any number of sound
problems or creative urges.
The Audio Spectrum, a Reference
In general, what we hear extends over a range of frequencies from 20 Hertz (Hz) to 20
Kilohertz (KHz). This equates to roughly ten and one third octaves, an octave being a
factor of two. The most perceived range lies between 300Hz to 3KHz, the region where
most voice information occurs. The audio spectrum may be divided into seven
frequency ranges. We will define these ranges in the following text.
Low Bass: 20Hz to 40Hz
This is the lowest of normally audible octaves. Below these frequencies, sounds are
more felt than heard. These subaudible frequencies are produced by earthquakes,
building vibrations, elephants and huge organ pipes. Low bass information include the
fundamental frequencies of the lowest keys on organs, synthesizers and pianos.
Mechanical rumble also falls within the range below 40Hz. These low bands on the
equalizer may be useful for tailoring the low frequency response of some speakers and
microphones.
Bass: 40Hz to 160Hz
These two octaves are normally perceived as the bass frequencies. Instruments such
as the electric and string bass, tuba, bass drum and the lower notes of keyboard
instruments fall within this range. The bottom end of most music is reflected here.
Mid Bass: 160Hz to 315Hz
In this octave, the transition between bass and midrange occurs. Low frequency
crossover points in speaker systems are usually selected in this range. Modification of
voice and drum fundamentals as well as the character of the upper bass and lower
brass instruments can be achieved by manipulating the levels of these frequencies.
Mids: 315Hz to 2.5KHz
The fundamental frequencies of voice and musical instruments occurs within these
three octaves. The upper harmonics of bass instruments also falls within this range.
The intelligibility of speech falls within this range of frequencies. Just as a point of
reference, these three octaves are about the same bandwidth as a telephone.
Upper Mids 2.5KHz to 5KHz
In this octave, what we perceive as presence, definition and attack are subject to
control. Boosting these bands adds crispness while cutting them eliminates vocal
sibilants such as hiss. Your ear is most sensitive in this frequency range.
Highs: 5KHz to 10KHz
Brilliance, vocal fricatives and intensity of the sound are adjusted in this frequency
range. The snap of percussive instruments especially cymbals and the harmonic
Summary of Contents for XL 231
Page 1: ...OPERATION MANUAL ...
