Hybrid Audio Technologies Legatia SE Carbon - Manual (Page 7)

Legatia SE Carbon User’s Manual ©Hybrid Audio Technologies Page 7 of 30
with low moving mass. Carbon fiber is acknowledged as being an exceptionally strong material, but
exhibits edge-mode distortion at high frequency, and therefore should be appropriately filtered using
active crossovers, or custom passive crossovers. By nature, the carbon fiber cone and dustcap are
water resistant.
Suspension
All Legatia SE Carbon midbass drivers include a rolled “double S” surround made of treated cloth
which is highly consistent. The surround topology terminates mechanical vibrations well, having a
low stiffness for positive damping of resonances. The surround, which acts as an air seal between
the cone and the basket, adds to the restoring force of the spider. Another function of the surround is
to absorb cone flexure waves as they are transferred up the cone. You'll also know a Legatia SE
Carbon midbass design by its double-S surround; this design feature allows for the use of a smaller
height grille, and more flexibility in mounting options. The surround is also instrumental for taming
edge mode distortion.
The spider material was chosen for optimal performance in all models; the spider is a 90/10
cotton/Nomex blend with single-dip low viscosity phenolic. This material provides the stiffness
desired without being overly brittle or stiff, where vibrations in the spider are well damped and do not
translate into the former or the cone.
Basket
The basket of the Stage VI Legatia SE Carbon series drivers are a shared design with the same
size/diameter drivers in the Stage VI Legatia SE, and Stage V Legatia drivers, for easy change-out
potential; the frames of similarly-sized drivers are interchangeable in mounting topology. The basket
is a high-quality cast aluminum design, and contains a large flange providing for the mounting of the
driver via four screw holes. The Legatia SE Carbon frame features large openings behind the cone to
eliminate chuffing and other aerodynamic-based noises, as well as provides adequate communication
to the back of the cone for acoustic suspension and proper operation.
Thiele/Small Parameters Introduction
Acoustics pioneers Neville Thiele and Richard Small developed a way to predict speaker
performance and frequency response. These parameters are known collectively as “Thiele/Small
Parameters”, and are divided into physical characteristics and response parameters:
The Physical Characteristics of a speaker are:
Re:
The D.C. resistance of the voice coil measured in Ohms.
Sd: The surface area of the speaker’s cone.
BL: The magnetic strength of the motor structure.
Mms: The total moving mass of the speaker including the small amount of air in front of and behind
the cone.
Cms: The stiffness of the driver’s suspension.
Rms: The losses due to the suspension.
The Thiele/Small Response parameters are: