McIntosh MS120

6
Ported High Pass System
Cut-a-Way Side View
Sealed High Pass System
Cut-a-Way Side View
Installation and Enclosures
Installation and Enclosures
Formulas for Calculating Port Lengths:
It is recommended that a qualified professional install all
McIntosh Automotive Products.
McIntosh Subwoofers are designed to operate in the
bass frequency range below 120Hz and should be used in
conjunction with McIntosh Component Loudspeaker com-
binations to reproduce the full audio frequency range.
Subwoofers need not be physically close to midrange and
tweeter speakers in order to maintain good imaging and
system frequency balance.
A custom loudspeaker enclosure constructed according
to the recommendations in this manual will result in the
best performance from a McIntosh subwoofer. The enclo-
sure should be constructed with high-density particleboard.
To ensure minimum cabinet vibration, the enclosure panels
should be at least ¾ inch thick, with adequate cross bracing
to increase stiffness. Ports may be constructed with plastic
pipe or cardboard tubing. The subwoofer should be
mounted in the enclosure so it radiates in a horizontal
plane.
Refer to the notes, charts and drawings in this manual
for recommended dimensions of three different types of
subwoofer enclosures and four different maximum power
ratings.
NOTES:
1. Use the enclosed template to locate and cut the loudspeaker
mounting holes.
2. Install the Subwoofer using the supplied gasket.
3. Enclosure dimensions of Depth, Width and Height listed in
the charts are internal measurements in inches. Volume
measurements listed in the charts are of the air in the
enclosure in cubic feet and do not take into account the
volume occupied by the port, the loudspeaker or any internal
braces you may have added. Port length is in inches and
port surface area is in square inches.
4. All ports are round with an inside diameter of 4 inches and
flared at both ends. If you wish to use a Non-Round Port or
a different Port diameter, use the formulas below to
determine dimensions. For Bandpass enclosures, the Volume
in the formula must be the Front Volume.
5. All Resonance frequency indications are in Hertz.
6. Max Power is in Watts.
Port Length =
(round)
8466 x Internal Port Radius
2
Volume x Resonance Frequency
2
- 1.463 x Internal Port Radius
Port Length =
(non-round)
2695 x Internal Port Surface Area
Volume x Resonance Frequency
2
- 0.825 Port Surface Area
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