Ultimate Performance Subwoofer
Chances are you've read or heard at some time that adding a
subwoofer to a system built around electrostatic speakers is nearly impossible.
Although that's not necessarily true (and we have the subwoofers to prove it),
the idea is grounded in experience. For many years subwoofers and electrostats
did not blend very well. Turn on the sub and maybe you got the deeper, stronger
bass you were looking for but that wonderful electrostatic snap and midrange
clarity were, if not gone, now smeared and disconnected.
Our goal, when we began our first subwoofer project, was to
deliver the good stuff — deep, tight, powerful bass — and none of the bad. We
wanted to build subwoofers that, when combined with ultra-fast electrostatics
or conventional cone speakers, would blend seamlessly to the very bottom of the
frequency extreme. BalancedForce subwoofers are the full realization of years
of engineering by the MartinLogan team combined with the latest innovations in
advanced digital signal processing, amplification, electrical system designs,
and room correction.
Opposing Aluminum Element Woofers
for Deep, Clean Bass
Dual low-distortion woofers pair a high-power magnet
structure with 10- and 12-inch aluminum cone diaphragms to deliver huge
excursion and sound output while preserving minute bass details, all without a
hint of distortion. The cone material's exceptional damping properties ensure
the smooth, non-resonant response necessary for seamless blending with
high-resolution full-range loudspeakers.
These woofers, spaced 180 degrees apart in a 'BalancedForce'
configuration, operate in exact opposition, to nullify distortion causing
cabinet vibrations and deliver pure bass energy. Traditional subwoofer
enclosures suffer from an equal and opposite reaction to the cone's movement,
generating acoustic vibrations within the cabinet. You feel this by touching
the cabinet. Although the "physics" of this phenomenon actually cause
a subwoofer cabinet to resonate or even dance, most subwoofer designers apply
weight or mass to the cabinet to minimize such disturbances, but still leave
one byproduct—"smeared bass". BalancedForce is an elegantly simple
solution that removes the variable of cabinet vibration contributions from the
Advanced Ultra-Efficient D-Class Amplifier
BalancedForce subs match powerful proprietary switching amps
with incredible woofer drivers resulting in tightly defined bass while keeping
distortion at the lowest possible levels. The BalancedForce 210 features an
850-watt class-D switching amplifier capable of a 1700-watt peak operating at
over 90% efficiency. Low-noise, high-power transformers and switching power
supplies feature high-quality MOSFET transistors, noise-suppression networks,
and control circuitry to provide tremendous levels of current with extremely
low levels of distortion. Split power supply rails minimize distortion while
maximizing switching efficiency. Military grade glass epoxy circuit boards,
temperature sensors, and protection circuitry guarantee quality sound and
reliable trouble-free operation.
PBK Room Correction & 25Hz Level Control
Although correct placement plays a key role in optimizing
subwoofer performance, positioning a subwoofer often requires compromises. The
optional MartinLogan Perfect Bass Kit (PBK, sold separately) uses a computer
and microphone to listen throughout the listening environment and tailor the
sub's performance to the unique acoustic properties of a room—resulting in
clean, powerful bass down to the lowest frequencies.
Additionally, a built-in 25Hz level control allows listeners
to adjust subwoofer output by ±10dB and compensate for excessive room gain by
cutting output in the 20- to 30-Hz range, or to accentuate the feeling of
deep-bass energy by augmenting those frequencies.
Custom Low-Pass Filters for
Individual Loudspeaker Models
Custom tailored low pass filters are available for nearly
every floor standing MartinLogan loudspeaker released in the last 30 years.
These optional custom filters adjust the subwoofer's low pass settings to
seamlessly blend with the roll-off characteristics of individual loudspeaker
models. Filters are easily installed via a user-friendly process involving a
USB thumb drive and are available for free download from MartinLogan.com/filters.
46 unique filters are currently available and additional filters will be added
as new speakers are released.
High-gloss black cabinets and top trim are standard. Top
trim is available in a variety of optional high-gloss, hardwood, and real-wood
Although ports are a convenient and cost-effective way of
increasing low-frequency output, their reliance on resonant energy impairs bass
quality. The BalancedForce subwoofer's sealed system exhibits less
transient-blurring group delay while maintaining smooth, consistent response,
regardless of music or movie source material.
Multiple Input Options
Simultaneous LFE and 2-Channel Connections for Seamless
Robust connection and control systems allow simultaneous
connection of both 2-channel stereo music and multi-channel home theater and
allows each source to have individual crossover and level settings, giving
listeners a perfect performance in every application. LFE input via RCA or XLR
effectively uses no low-pass filter, leaving crossover control to the
processor. Left and right RCA, XLR, and speaker level inputs integrate discrete
user-adjustable or speaker specific custom-installed audiophile grade low-pass
filters allowing different level and crossover points when playing back two channel
Top Mounted Controls
Top mounted controls are discretely hidden beneath a smoked
glass accent panel allowing easy access to fine tune the subwoofer's settings.
Access the top mounted control panel by pushing firmly on
the smoked glass panel. You'll find all of your standard subwoofer controls
like Level, Low-Pass Filter and Phase, plus some that are unique to
A unique tone sweep feature assists users in locating areas
in listening rooms where troublesome rattles or resonances may occur. A single
press of a button allows listeners to initiate a tone sweep from 120–20Hz. If a
rattle or resonance occurs in the room a second press of the button holds the current
frequency allowing the listener to investigate and identify the source.
An 'On/Auto (Trigger)/Off' switch controls the subwoofer's
energy saving feature. The 'On' setting prevents the sub from entering energy
saving mode. When set to 'Auto (Trigger)', the sub will turn on when a music
signal is detected and off after several minutes without a signal. If a 12-volt
trigger is connected, the triggering device will turn the subwoofer on and off.
Further flexibility is afforded by custom energy transfer
coupler (ETC™) spikes, which can enhance stability on thick carpets, or create
tighter coupling between subwoofer and floor to enhance overall sound quality.