Behringer DSP1100 User Manual page 8

As can be seen, human hearing has a very wide dynamic range of about 130 dB, which surpasses the range
of a DAT or CD player with an approximate range of 96 dB. From a physical point of view, a 6 dB boost
corresponds to an increase in loudness by the factor 2. However, the human ear perceives a signal to be
twice as loud as before only if it is boosted by about 10 dB. This will give you an idea of the variety of sound
manipulations that can be realized with the 24 filters of the FEEDBACK DESTROYER. For each filter, you
can apply a boost of +16 dB or a cut of -48 dB, i.e. you can boost the selected frequency by the subjectively
perceived factor 3 (physically x5) or attenuate it by the factor 27 (physically x250)!
The sound which an EQ produces not only depends on the selected frequency and the amount of gain
(expressed in dB); the bandwidth of the filters also plays an important role. Here, we generally use the so-
called absolute bandwidth of a filter, which is measured from the lower to the upper cutoff frequency. Starting
from there, you can divide the absolute bandwidth by the filter's center frequency to calculate the relative
bandwidth. The quality factor (Q) is simply the reciprocal value of the relative bandwidth.
0 dB
-2 dB
-4 dB
-6 dB
-8 dB
-10 dB
-12 dB
200 Hz
8
160
140
120
100
80
60
Quiet Apartment
40
Recording Studio
20
Falling Leaves
Threshold Of Audibility
0
Fig. 1.1.: Dynamic range of human hearing
Filter attenuated by 8 dB at 1kHz
-3 dB
Fig. 1.2: Typical equalizer filter curve
1. INTRODUCTION
Threshold Of Pain
Power Drill
Machinery Hall
"Loud" Office
Normal Conversation
Bandwidth = 600 Hz
Center frequency
1 kHz
Jet Engine
= 1 kHz
5 kHz