MartinLogan Prodigy user manual Bass Control Switch, High Amplifier

With horizontal bi-amping, one amplifier drives the high pass (ESL) section while the second amplifier drives the low pass (WOOFER) section. To horizontally bi-amp your Prodigys you must loosen the binding posts and remove the jumper clips. Connect the low frequency amplifier to the lower set of binding posts of both speakers. Connect the high frequency amplifier to the upper set of binding posts. Next, connect the left and right preamplifier outputs to the appropriate left and right inputs of both amplifiers (See Figure 3).

Vertical Passive Bi-Amplification

Jumper clips removed

Low Amplifier

speaker output

High Amplifier

speaker output

The very nature of vertical bi-amping dictates that both amplifiers be identical. With vertical bi-amping, each of the stereo amplifiers is dedicated to one speaker. For instance, the left channel of each amplifier drives the low pass (WOOFER) section while the right channel drives the high pass (ESL) section. To vertically bi-amp your Prodigys you must loosen the binding posts and remove the jumper clips from both speakers. Starting with one speaker, connect the right channel to the lower binding posts and the left channel to the upper binding posts. Repeat the same procedure for the other speaker. Connect the left preamplifier outputs to both inputs of the left channel amplifier and the right preamplifier outputs to both inputs of the right channel speaker (See Figure 4).

PRODIGY TM
flat	ESL
+3db
Bass Control	Woofer

Figure 3. Horizontal passive bi-amplification. One Channel shown.

Bass Control Switch

On the rear panel of the Prodigy electronics module, beside the Signal Input binding posts, is a two position Bass Control switch that allows you to select the type of low frequency response you desire.

The 0 dB (flat) position is considered the normal setting for most rooms. However, if you feel that the bass in your system is too weak relative to the mid and high frequencies, simply select the +3 dB position. This switch position will increase the output of the woofer by 3 dB centered around 50Hz.

Jumper clips removed

Left Channel Amplifier

speaker output

Some experimentation with these two switch settings will allow you to find the optimal tonal balance for your specific taste, room and equipment.

PRODIGY TM
flat	ESL
+3db
Bass Control	Woofer

Figure 4. Vertical passive bi-amplification. One Channel shown.

Operation 9