BBE 362 - Manual (Page 3)

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Precautions............................................................................................................................................................................................... 1
BBE Process Description......................................................................................................................................................................... 1
Product Description.................................................................................................................................................................................. 2
Controls/Connections............................................................................................................................................................................... 3
Applications ............................................................................................................................................................................................. 4
Application Diagrams........................................................................................................................................................................... 5-9
Specification/Service/Maintenance/Warranty....................................................................................................................................... 10
Calibration Procedures........................................................................................................................................................................... 11
Schematic Diagrams......................................................................................................................................................................... 12-13
Congratulations on your purchase of the BBE 362 Sonic Maximizer, a two channel signal processor that will benefit any
sound reproduction system. You now own a very unique signal processing device with no other equal in the audio world. Whether
you purchased the BBE 362 for your home studio or club P.A. system, you will find the unit’s rugged construction and careful
electronic design a welcome addition to your audio system.
This manual will help you use BBE more effectively and in ways of which you may not be aware. Reviewing of the
information contained in this manual will answer most of the common questions that our service department receives. But if you
still have questions, please feel free to call (714) 897-6766.
TABLE OF CONTENTS
The BBE Process-"What it is"
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 essential 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 complex
time and amplitude relationships between the fundamental and harmonic components of a given musical note or sound. These
relationships define a sound’s "sound".
When these complex relationships pass through a speaker, the proper order is lost. The higher frequencies are delayed.
A lower frequency may reach the listener’s ear first or perhaps simultaneously with that of a higher frequency. In some cases, the
fundamental components may be so time-shifted that they reach the listener’s ear ahead of some or all of the harmonic components.
This change in the phase and amplitude relationship on the harmonic and fundamental frequencies is technically called
"envelope distortion." The listener perceives this loss of sound integrity in the reproduced sound as "muddy" and "smeared." In
the extreme, it can become difficult to tell the difference among musical instruments, for example, an oboe and a clarinet.
BBE Sound, Inc. conducted extensive studies of numerous speaker systems over a ten year period. With this knowledge
it became possible to develop an ideal speaker and to distill the corrections necessary to return the fundamental and harmonic
frequency structures 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 It Works"
The BBE Process imparts a pre-determined phase correction to the high frequencies where most harmonic information
exists. This is done by breaking the signal into three sub-bands or groups; the low frequency group which is crossed over at 150Hz,
the mid-range group which is crossed over at 1200Hz and the high frequency group that handles everything else up to 20kHz.
The low group is delayed about 2.5 ms (milliseconds) via a group delay within a passive low pass filter. The front panel
control allows for either a flat response or a boost of the lows 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 high quality VGA (Voltage Controlled Amplifier). The high group is used as a point of reference to make
dynamic amplitude corrections to the high frequencies.
The RMS average loudness detectors continuously monitor both the mid-range and high frequencies to compare the relative
harmonic content levels of the two bands and apply the appropriate 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.
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