Specifications

M&K Sales Training Outline
page 6
May 98
http://www.mksound.com
M&K uses only
sealed-box cabinet
designs for superior
transient response
and Deep Bass
All M&K Subwoofers (and Satellites) are sealed-box designs, tightly
packed with highly efficient sound absorbing material. This configura-
tion delivers the best transient response, and is the only design ca-
pable of producing true Deep Bass.
Good transient response means that the speaker responds quickly
to input signals, with a quick start and (especially) a quick stop. Speak-
ers with poor transient response have a blurred, muddy sound with
little pitch definition. Deep Bass refers to the ability of the speaker to
produce significant output to very low frequencies below 20 Hz, which
is needed to produce the "startle factor."
M&K cabinets are very heavily braced (2 x 4s are used in both
the S-5000 and MX-5000!) to provide the most stable platform for the
drivers and to avoid the resonances, buzzes and rattles that are sur-
prisingly common in competitive subwoofers. Flimsy, unbraced cabi-
nets produce an easily recognized sound. They sound cheap!
Many competitive subwoofers are vented designs, using ports or
passive radiators. These designs have inherently poor transient re-
sponse, producing a boomy, uncontrolled sound you are familiar with.
They may play fairly loud, but their sound is boomy and muddy, and
that sound becomes fatiguing to listeners very quickly. Most produce
a very audible air turbulence noise from their ports when producing
certain frequencies. This noise can draw your attention to the
subwoofer and make its sound directional. Most of these subwoofers
respond poorly or not at all to very rapid impulses, such as flamenco
dancers' foot stomps on a wooden floor.
Like a bottle filled with water that produces one particular frequency
when you whistle across its opening, the sole purpose of a port or
passive radiator is to make a cabinet resonate at or near the tuned
frequency of the port. This generates added output (3 to 6 dB) at that
frequency, but there is a price to pay for that poorly damped extra
output, because with this design internal damping material cannot be
used.
Remember that a speaker driver is radiating as much sound inside
the cabinet as it is filling the room. This is why all M&K subs are tightly
stuffed with highly efficient absorbing material to absorb much or all of
the sound inside the cabinet. When a cabinet does not have this ab-
sorbing material, the sound in the room becomes muddy.
In a ported
speaker, stuffing cannot be used.
The other fatal weakness of vented designs is their extremely rapid
rolloff below their tuned resonance frequency (usually well above 30
Hz). Below that frequency, the woofer's response drops off so quickly
it essentially disappears, making it unable to reproduce subsonic tran-
sients. Vented boxes roll off at twice the rate of sealed box speak-
ers (24 dB per octave), and their active driver and vent are actually
out of phase with each other, so they cannot produce Deep Bass.
Deep Bass Subwoofer Cabinets Designs
Weaknesses of vented
(ported and passive
radiator) designs