Bi-Amplified And Tri-Amplified Systems - Mackie M-2600 Owner's Manual

BI-AMPLIFIED AND TRI-AMPLIFIED
SYSTEMS
Most speaker systems in use today are of
the two-way or three-way variety. Cone speak-
ers are good at reproducing low and mid-range
frequencies, but not high frequencies. Likewise,
compression drivers are good at reproducing
high frequencies, but definitely not low frequen-
cies. This is why two-way, three-way and even
four-way speaker systems were developed —
to improve the efficiency of each individual
driver by requiring it to reproduce only the
frequencies that it reproduces best.
One method of accomplishing this is
through the use of a passive crossover network
between the amplifier and the speaker(s).
Often the passive crossover is built into the
cabinet along with the various drivers. The
crossover divides the high-level speaker signal
into frequency bands, which are then directed
to the appropriate driver. There are some draw-
backs to this method, however. The passive
crossover adds reactance to the load that the
amplifier sees, which can affect the damping.
Power is wasted as heat across the resistors in
the crossover, reducing the amount of amplifier
power available to the drivers themselves.
FROM SIGNAL SOURCE
(MACKIE MIXING CONSOLE)
FROM SIGNAL SOURCE
(MACKIE MIXING CONSOLE)
Passive Crossover System
FROM SIGNAL SOURCE
(MACKIE MIXING CONSOLE)
TO HIGH-FREQUENCY
AMPLIFIER
LOW-LEVEL
2-WAY ACTIVE
CROSSOVER
TO LOW-FREQUENCY
AMPLIFIER
Biamplified System with External Active Crossover
38
FR SERIES
POWER AMPLIFIER
(STEREO MODE)
+
CH 1 CH 1
IN OUT
–
–
CH 2 CH 2
IN OUT
+
FROM SIGNAL SOURCE
(MACKIE MIXING CONSOLE)
3-WAY ACTIVE
CROSSOVER
FR SERIES
POWER AMPLIFIER
(STEREO MODE)
CH 1
TWEET
+
INPUT
CH 1
OUT
–
CH 2
–
INPUT
CH 2
OUT
+
WOOF
Biamplified and triamplified systems use
separate power amplifiers to power each indi-
vidual low-frequency and high-frequency
driver. An electronic crossover (a.k.a. active
crossover) is located between the signal source
and the power amplifier. The advantages of
this method include:
• Increased headroom available from each
amplifier, since they're amplifying only a
portion of the entire audio spectrum.
• Improved damping factor because the
amplifier output is connected directly to
the driver.
• Improved efficiency because there are no
passive resistors to dissipate heat; and
• Flexibility to choose the optimum cross
over frequency and crossover slope for
the individual drivers in the system.
The M•2600's internal crossovers are
electronic (active) and allow biamplification
above and below a user-selectable crossover
point of 60Hz, 90Hz, or 120Hz. See the
application diagrams on pages 13-16.
TWO-WAY SPEAKER CABINET
HIGH-LEVEL
PASSIVE
CROSSOVER
TWO-WAY SPEAKER CABINET
HIGH-LEVEL
PASSIVE
CROSSOVER
CH 1
TO HIGH-FREQUENCY
INPUT
AMPLIFIER
LOW-LEVEL
CH 2
TO MID-FREQUENCY
INPUT
AMPLIFIER
CH 1
TO LOW-FREQUENCY
INPUT
AMPLIFIER
Triamplified System with External Active Crossover
HIGH FREQUENCIES
TO TWEETER
LOW FREQUENCIES
TO WOOFER
HIGH FREQUENCIES
TO TWEETER
LOW FREQUENCIES
TO WOOFER
FR SERIES
POWER AMPLIFIER
(STEREO MODE)
TWEET
+
CH 1
OUT
–
–
CH 2
OUT
+
MID
FR SERIES
POWER AMPLIFIER
(BRIDGE MODE)
+
CH 1
OUT
–
WOOF
–
CH 2
OUT
+