Active Bi-Amplification - MartinLogan Motion 60 XTi User Manual

Horizontal Passive Bi-Amplification
Horizontal bi-amping allows you to use two differ-
ent types, models or brands of amplifiers (i.e. tubes
on top, transistor on the bottom). However, we rec-
ommend that you use two identical amplifiers (i.e.
same brand and model). If you must use two differ-
ent amplifiers, it is essential that they have the same
gain or that one of the two have adjustable gain
so that you can match their gain characteristics. If
the amplifiers of choice do not have the same gain
characteristics, then a sonic imbalance will occur.
With horizontal bi-amping, one amplifier drives the
high-frequency section of the speaker while the sec-
ond amplifier drives the low-frequency section. To
horizontally bi-amp your speakers 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 (Fig. 3).
Fig. 3: Horizontal bi-amplification connection.
One channel shown.
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Vertical Passive Bi-Amplification
The very nature of vertical bi-amping dictates that
both amplifiers be identical. With vertical bi-amp-
ing, each of the stereo amplifiers is dedicated to
one speaker. For instance, the left channel of each
amplifier drives the low-frequency section while the
right channel drives the high-frequency section. To
vertically bi-amp your speakers 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 amplifier (Fig. 4).

ACTIVE BI-AMPLIFICATION

We do not recommend active bi-amplification. The
internal crossover can not be bypassed. This con-
nection method seriously degrades performance.
Fig. 4: Vertical bi-amplification connection.
One channel shown.