For more than 60 years, JBL has been delivering
products embodying the technology developed in
the professional arena – equipping leading recording
studios and movie theaters, as well as live-music
reinforcement in venues ranging from dance clubs to
Woodstock. We continue to transform this expertise
into products that provide the impact and excitement
of a live performance. The JBL
®
experience is for
enthusiasts who won’t settle for anything less than
“live” at home or on the go.
The JBL Power Series
®
subs and PB1220 enclosure
have been engineered to put you in the front row at
your favorite concert, whenever and wherever you
happen to be listening. They produce deep, solid, tight
bass that can only be delivered by the leading brand in
concert sound.
KEVLAR
®
-IMPREGNATED-
PAPER WOOFER CONES
This combination has been chosen for its high strength-
to-weight ratio, and is formed using a proprietary
manufacturing process. Its stiffness relieves stress
concentrations that may accumulate at the base of the
cone in high-power and high-pressure applications.
NITRILE-BUTYLENE-RUBBER
ONE-PIECE SURROUND AND
GASKET
This material provides an optimal blend of elasticity
and internal damping. The size of the roll is optimized
to offer good long-throw linearity with the proper
amount of control and stability at excursion limits.
PROGRESSIVE SPIDER
This provides better control at excursion limits than a
linear spider. The benefit is reduced distortion at high
output levels.
VENTED POLEPIECES
Additional cooling is provided to the motor structure.
The subwoofer’s thermal capabilities are augmented,
increasing power handling.
SLIPSTREAM PORT
The JBL PB1220 loaded enclosure’s performance
is superior to that of competing loaded enclosures,
primarily due to the revolutionary Slipstream port. The
Slipstream port provides lots of surface area outside
the box so that the air stays stuck together – the
engineers call this an “adverse pressure gradient”.
That gradual change from high pressure to low pressure
eliminates the distortion known as “whacking”. Because
the port’s area in the middle is much smaller than the
mouth of the port, the port can be
much shorter than
a cylindrical port. That means the Slipstream port can
fit into regular boxes. Stickiness outside the box is
maximized by increasing pressure, and stickiness inside
the port is minimized by reducing velocity. The benefit of
this technology is more bass output, with greatly reduced
port noise and distortion.
