Abrahamsen FS401, Owner'S Manual

Page: 5 / 14

5
Introduction
This user manual contains important information on the
placement, installation, and operation of your ABRAHAM-
SEN © product. Please read this information thoroughly. A © ©
good understanding of these details will help ensure satis-
factory operation and long life for your product.
The story behind the sound
In 1972 Dr. Otala and Mr. Lohstro finished their work in
analysing transistor amplifiers to determine what actually
created the ”transistor sound” in general transistorized
designs. The results of their innovative design work were
incorporated in the legendary 25 watt amplifier.
This product was the first commercial transistor amplifier
to use this new design approach, and the amplifier was
immediately recognised as dramatically more musical and
dynamic sounding than any other transistor amplifier. The
same design philosophy has been constantly updated by
additional research and development. This philosophy forms
the basis of the new ABRAHAMSEN © design. © ©
After the 25 watt amplifier had established a new standard
for transistor amplifiers, research was undertaken to find
ways to make the amplifier even better, and to extend its
highly musical sound quality to more powerful amplifier
design.
In the beginning of the 70’s, while working with the amplifier
design a speaker was designed to go with the amplifier.
Such a speaker was needed as normal dynamic speakers
on the marked at that time, did not have the sound quality
needed to cope with the amplifier. Throughout the develop-
ment period of Electrocompaniet products, we have always
used our own speaker design as a “reference”, but not as
a commercial product. To day we are proud to present a
speaker that we feel is commercially ready with respect to
both sound and aesthetic qualities.
Introduction to the loudspeaker design
The loudspeaker has been designed and manufactured to
provide high quality reproduction of music and speech in a
domestic environment. The tweeter (high frequency unit)
has been specifically designed to maintain constant direc-
tivity over its frequency range; thus providing a wide, even
listening area up to ±30° from the tweeter axis. The short
fiber base/midrange units provide low coloration at high
frequencies due to well damped
cone modes of vibration; simple crossover filters are suffici-
ent to marry the responses of these units to the tweeter. The
bass reflex port is integrated into the base of the cabinet
providing strong coupling to the listening room at one of its
boundaries (the floor). The cabinets are manufactured from
an aluminum extrusion and MDF; this provides a stiff, well
damped base for the drive units.