Bi-amplification applications – Samson 4060/4120 User Manual

Page 10

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Bi-amplification Applications

Because the Samson Servo Quad Amplifier actually contains four discrete power
amplifiers in a single chassis, it is particularly well-suited for use with bi-amped
speaker systems. These systems utilize active crossover networks (sometimes
called electronic crossovers) that are specially designed to handle low-wattage
line-level signals. As shown in the illustration on the right, the crossover in such
a system is placed just prior to the power amplifier in the signal chain.

The circuitry in a two-way active crossover network divides the incoming signal
into its high and low frequency components. Those frequencies above a
specified crossover point are sent to one discrete output and those below the
crossover point are sent to the other. Each output is then connected to a
separate power amplifier channel input. In this way, one amplifier powers the
loudspeaker’s low frequency drivers (“woofers”) and another powers the
loudspeaker’s high frequency drivers (“tweeters”).

The advantage to bi-amping is not only enhanced loudspeaker performance
(since each speaker driver is receiving optimized signal) but also greatly reduced
distortion. This is because most of the energy in musical signals lies in its low
frequency components (next time you’re listening to a piece of popular music,
contrast the level of kick drum and bass guitar to the other instruments). When
both low and high frequencies are present in a signal, these high-energy low
frequency signals can eat up all the available headroom in a power amplifier,
leaving none for the higher frequencies. The end result is nasty clipping
distortion of the high frequency material. The use of an active crossover network
effectively eliminates this problem—in fact, you’ll get cleaner, perceptively louder
signal than if you were to use a single higher-power amplifier instead!

Of course, with four amplifiers at your disposal, you can use your Samson
Servo Quad Amplifier to bi-amp both the left and right signals in a stereo system.
Simply use a stereo active crossover network and route the two left outputs
(low and high frequency) to the Servo Quad Amp channel inputs 1 and 2
and the two right outputs to channel inputs 3 and 4. You can then use the
front-panel input level controls to adjust the relative levels of each output signal.

10

LEFT
INPUT
SIGNAL

RIGHT
INPUT
SIGNAL

ACTIVE CROSSOVER

NETWORK

LEFT

LF

OUT

HF

OUT

RIGHT

LF

OUT

HF

OUT

CH1

IN

CH2

IN

CH3

IN

CH4

IN

CH1

OUT

CH2

OUT

CH3

OUT

CH4

OUT

SERVO QUAD

AMPLIFIER

LEFT
WOOFER
INPUT

RIGHT
WOOFER
INPUT

LEFT
TWEETER
INPUT

RIGHT
TWEETER
INPUT

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