BBE Sonic Maximizer BBE 422 - Manual (Page 3)

Congratulations!
Thank you for buying the BBE Model 422 MAXIE Sonic Maximizer. You now own a very unique signal processing device with
no other equal in the audio world. Whether you purchased the BBE 422 for your home studio or club RA. 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 the BBE 422 more effectively and in ways of which you may not be aware. Review of the
information contained in this owner's manual will answer most of the common questions that our service department receives.
But if you still have questions, please feel free to call toll-free (In USA) 1-800-233-8346 or (In CA) 1-800-558-3963.
The BBE^” Process ^ “What Is It?”
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 have proved unsolvable and were thus relegated 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 the
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 order 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 can reach the listener’s ear ahead of some or all the
harmonic components.
This change in the phase and amplitude relationship of 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 needs for 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 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 0.5 ms and passes through an active band-pass filter. The mid group is used as
a point of reference to make dynamic amplitude corrections in both positive and negative directions to the high frequency
group which has been passed through a high quality VGA (Voltage Controlled Amplifier).
Two 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.