Bi-Amplification Applications - Samson 4060/4120 Owner's Manual

Quad amplifier

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Table of Contents

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.