BBE 362SW - Manual (Page 4)

The BBE Process Explained
What is BBE? (some big words to describe the mysteries of our little black box)
Loudspeakers have difficulty dealing with the electronic signals supplied by an amplifier. These
difficulties cause such major phase and amplitude distortion that the sound reproduced by a
speaker differs significantly from the sound produced by the original source.
In the past, these problems proved unsolvable and were thus delegated to a position of
secondary importance in audio system design. However, phase and amplitude integrity is essen­
tial to accurate sound reproduction. Research shows that the information which the listener
translates into the recognizable characteristics of a live performance are intimately tied into com­
plex time and amplitude relationships. These relationships define a sound's "sound".
When these complex relationships pass through a speaker, the proper order is lost. The
listener perceives this loss of sound integrity in the reproduced sound as "muddy" and "smeared".
BBE Sound, Inc. conducted extensive studies of numerous speaker systems over a ten year
period. With this knowledge, it became possible to identify the characteristics of an ideal speaker
and to distill the corrections necessary to return the fundamental and harmonic frequency struc­
tures to their correct order. While there are differences among various speaker designs in the
magnitude of their correction, the overall pattern of correction needed is remarkably consistent.
The BBE process is so unique that 42 patents have been awarded by the U.S. Patent Office.
How does BBE work? (a mildly technical expose - for those that need to know)
The BBE Process imparts a predetermined phase correction to the high frequencies where
most harmonic information exists. This is done by breaking the signal into three sub-bands or
groups:
a. ) LOWS (20Hz-150Hz)
b. )MIDs 050Hz-1200Hz)
c. ) HIGHs (1200Hz-20kHz).
The low group is delayed about 2.5 ms (milliseconds) via a delay within the passive low pass
filter. The front panel LO CONTOUR control allows for either a flat response or a boost at 50Hz.
The mid-range group is delayed only about 0.5ms and passes through an active band-pass filter
while the high frequency group is passed through a VGA (Voltage Controlled Amplifier). The high
group is used as a point of reference to make dynamic amplitude corrections to the high frequen­
cies.
The RMS average loudness detectors continuously monitor both the mid-range and high fre­
quencies to compare the relative harmonic content levels of the two bands and apply the appro­
priate amount of control voltage to the VGA, thereby determining the amount of high frequency
harmonic content present at the final output of the BBE processor.