Configuration
The LS720P can be
used in several different
configurations. The basic
system is a single LS720P
used for each full-range
loudspeaker (multiple
LS720Ps can also be used
with individual full-range
loudspeakers). A single
LS720P can also be used with
a stereo system if both Input A
and Input B are used..
Note: Left and right signals
can be directly connected
to a single LS720P maintaining
their stereo separation. Plug the
two
audio signals (left and right) into the Input A
and Input B jacks, the LS720P combines the
line-level signals properly but also allows you
to connect the respected left and right full-
range powered loudspeakers by connecting
them directly to the Thru jacks.
Note: When sending a mono source signal into
the LS720P, you can use either Input A or Input B.
1. Input Level Switch
The Input Select switch is provided to choose
between line-level and speaker level. The line-
level position is for use when the LS720P is fed
a signal directly from a processor, electronic
crossover or the output of an un-powered mixer.
When using the line-level mode, the use of
balanced (Tip, Ring, Sleeve) and/or XLR cables
will reduce the unit’s sensitivity to hum and buzz.
This switch should be set to speaker level when
the LS720P is fed from the output of an amplifier
or a powered-mixer.
WARNING: Do not plug in two speaker level
sources to a single LS720P.
2. LS720P Level Control
The Level control adjusts the amount of bass
added to the sound system by the LS720P. This
Level Control adjusts for the relative sensitivity of
the companion full-range loudspeakers and the
desired system frequency response. This control
should be set by listening while operating at a
medium level and then not changed.
Note: It is not recommended
to set this control at high levels
since the limiter determines the
output level.
Note: A setting of 0 dB on the
LS720P Level control is the correct
starting point when setting up
a sound system. From there,
adjustments can be made for the
best sound. The 0 dB mark refers to
the setting that will give full power
when the line input is used and the
input signal is at a level of +4 dBV.
3. Boost Frequency Control
The Boost Frequency control allows the user
to change the character of the subwoofer
sound. This control will have less effect when
operating into limiting.
4. HF Rolloff Frequency Control
The HF Rolloff Frequency control varies the
frequency at which the LS720P rolls off the high
frequencies, which provides part of a crossover
function. This crossover function also combines
with the natural low frequency rolloff inherent
of the full-range loudspeaker (when the LS720P
is not used with a separate processor). As an
example, a Yorkville élite processor may be
used to provide the LF rolloff of the full-range
loudspeaker. Ideally the LS720P would then be
wired ahead of this processor. In this case the
LS720P HF rolloff should match the LF crossover
point of the separate processor. A separate
processor may be used ahead of the LS720P in
which case the LS720P HF rolloff should be set to
maximum. Most Yorkville powered loudspeakers
include a LF rolloff switch, which makes it
unnecessary to use an electronic crossover.
5. Input Jacks
The inputs are set up to make it easy to hook up
your LS720P to almost any audio system with a
minimum of hassles. There are two groups of input
jacks, Input A and Input B. Each set provides a
Thru connection to allow daisy-chaining. Input A
jacks includes ¼ inch jacks, a male XLR jack and
female XLR jack. Input B jacks use a single XLR
male jack and a single female jack. If these two
sets of jacks are used simultaneously the signal is
mono summed within the LS720P to generate the
signal to drive the subwoofer.
Introduction
Congratulations on your purchase of the LS720P. The LS720P is a premium-quality integrated subwoofer
and power amplifier. It’s been designed as an easy-to-setup addition to any P.A. and will extend the
bass of a typical sound system with the least amount of complication.
Note: The LS720P is primarily intended to operate with line-level signals, but will also work with
speaker level signals.
