Iiix operation, Crossover settings, Bass contour controls – MartinLogan Monolith III User Manual

Page 14: Your room and bass

Page14

Monolith III User's Manual

Crossover Settings

Before you do any formal listening,
you must set a pair of switches in the
crossover. However, if you are using
identical amplifiers (i.e. same make
and model) for the high and low-pass
sections of the Monolith, you may use
the factory settings and skip this step.

On the back panel of the crossover
there are two cut-outs that allow you
to access two red dip switches. These
switches adjust the low-pass gain so
that you may balance the gain
between the high-pass and low-pass
amplifiers if they have different gain
characteristics. We have even
enclosed a red "dip stick" tool to assist
you with this procedure.

The following formula will help you
calculate the relative gain of your
amplifiers:

Amplifier gain is defined as:

20 log

At right, in

Figure 5, is a list of switch

settings to help you select the proper
gain switch settings.

As you detent the switch towards the
ON

ON position, you are engaging that
switch. Each switch detent away from
position “4” either increases or
decreases the output of the low-pass
amplifier. In order to properly engage
a switch, you need to have all other
switches in the OFF

OFF

OFF position. If the

high-pass and low- pass amplifiers are
identical or have the same gain, the
system is designed to operate with
both switches set to “4” (Position “4”
represents 0dB of gain).

If equipped, the best way to obtain the

(Rated Output @ 8 ohms) x 8

(Rated Output @ 8 ohms) x 8
Input Sensitivity

Input Sensitivity

IIIx Operation

Bass Contour Controls

You will notice that there are two
controls on the front of the

MONOLITH

IIIx CROSSOVER. The left control is
labeled

frequency and the right

control is labeled

boost/cut. (See

Figure 6.) These are a very accurate
and precise pair of controls that allow
you to adjust your speakers output in
the most problematic area of music
reproduction; the bass region.

optimal setting is to locate the
microphone of a spectrum analyzer in
the room near your seating position,
play pink noise through the system
and begin to observe the relationship
of the electrostatic transducer and the
subwoofer at the crossover point
which is 125 Hz. Your gain settings
will be correct when the display is flat
and consistent. You want the energy
below 100 Hz to be roughly compa-
rable to the energy above 100 Hz. If
you now have reasonable tonal
balance from 60 Hz onward to 200
Hz, then you have the optimal
frequency balance at the crossover
point.

Keep in mind that specifications and
equipment can determine the best
place to begin, but your ears are the
most critical instruments available.
Listen to music and adjust for your
best personal balance.

None

*1
*2

2&1

3&1

4&1
4&2

GAIN

-6.0 dB
-4.5 dB
-3.0 dB
-2.0 dB
-1.5 dB
-1.0 dB

0 dB

+0.5 dB
+1.0 dB

5&2
5&3

6&3
6&5

7&6

GAIN

+1.5 dB
+2.0 dB
+2.5 dB
+3.0 dB
+3.5 dB
+4.0 dB
+4.5 dB
+5.0 dB
+6.0 dB

Figure 5

Figure 5: Low-pass attenuation switch settings.

NOTE: Start with "*" settings first, then fine

tune using the intermediate settings.

Your Room and Bass

Today we are finding that all elements
in the audio chain can and will affect
your system's performance. Of these
elements, your room is the worst
offender. Once the precisely tailored
musical signal is launched from your
speaker system, your room then has

its way with that
musical signal;
particularly with the
larger wave-
lengths of the
bass region. Your
room will enhance
and cancel certain
frequencies,
making a perfect
speaker look less
than perfect in the
best of instances
and like a jumbled
mess in the worst
of instances. The
front panel
controls of the
crossover can be
used much like an
accurate bass/