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
