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Rockford Corporation Engineers Granted U.S. Patent for New Class bd Digital Amplifier Technology

16 August 2000

Rockford Corporation Engineers Granted U.S. Patent for New Class bd Digital Amplifier Technology

    TEMPE, Ariz. - Rockford Corporation today announced that its engineers have 
been granted U.S. Patent 6,097,249 for new Class bd technology.  In Research & 
Development for three years, a new high-efficiency amplifier technology was 
shown to the press at the 1999 CES Show and has now been incorporated into a 
new digital amplifier topology, called Class bd.  This patent involves a new 
technology, known as STARDUST (Single Terminal Alternating Rail DUal Sampling 
Topology), for audio applications -- a novel form of Class BD amplification.

    STARDUST allows the bd class amplifier to put more than 1,000 watts of RMS
power in the hands of the serious car audio user -- and does so in a
relatively small size.  This improvement has been in commercial products since
the January 2000 introduction of the Rockford Fosgate model bd1000.1.
STARDUST is expected to be a common element of Rockford's continuing program
of digital amplifier development.

    When considering what you are getting for your dollar in relationship to
the power output, the STARDUST technology makes the Class bd amplifiers
(1,100 watts for $699.99) more affordable in relationship to other typical
class AB amplifiers since there is less current consumption from the charging
system.  In the case of Class bd amps, there is less heat generated due to the
Class bd STARDUST technology.  As a result, the cooler internals makes the
overall performance more reliable.

    "Conventional Class D amplifiers have been around for 60 years in theory
and about 30 years in practice," explains Gary Suttle, president and chief
executive officer, Rockford Corporation.  "The Class bd amplifier is highly
efficient at all power levels, and makes more power than traditional digital
amplifiers.  This technology will be used as a new amplifier platform for
future products.  We continually strive to produce leading edge, innovative
technology."

    Rockford's novel approach allows the first practical generation of
high-definition, three-level output pulses, in lieu of the two levels employed
in typical digital amplifiers.  STARDUST allows better digital amplifier
designs -- which can have analog, digital or mixed signal internal processing.
Designs can accommodate analog or digital inputs.

    Rockford Corporation is a designer, manufacturer and distributor of
high-performance audio systems for the mobile and professional audio markets.
Rockford's mobile audio products are marketed under the Rockford Fosgate and
Lightning Audio brand names.  Rockford's professional audio products are
marketed under the Hafler brand name.