Hybrid Audio Technologies Legatia - Manual (Page 22)

Legatia User’s Manual ©Hybrid Audio Technologies Page 22 of 65
Voice Coil
The voice coil diameter of the L4 is a large 25.5mm (1-inch), which is the proper balance between
size and moving mass in super high-end mobile audio midranges/full-range drivers. The voice coil
diameter serves several key functions: elevated power handling, dissipation of heat (thereby lowering
power compression), and maximizing the size of the magnet assembly for enhanced motor
compliance. The voice coil is high-purity aluminum, which is superior to copper for heat dissipation,
as well as significantly reduced moving mass. The result is an extremely light weight winding with
good power handling and low inductance.
Suspension
The inverted surround is butyl rubber which is highly consistent, and does not suffer the variance of
natural rubbers. This rubber surround terminates mechanical vibrations well, having a low stiffness
for positive damping of resonances. The spider material was chosen for optimal performance; 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.
Cone
Like other Legatia midrange designs, you will find no composite or metal cone materials used on the
L4, as our approach to point-sourcing is to allow the Legatia midbass/midrange driver to effectively
play into upper treble frequencies. The Legatia L4 is a cone-type driver consisting of a proprietary
hybrid paper diaphragm with extremely low moving mass. Paper is widely acknowledged as the best-
damping material, as it provides the near optimum balance of strength and weight. The cone has
been treated with a water resistant element at the rear to accommodate door mounting, or other
areas prone to occasional contact with liquid. The cone design offers a wide dispersion pattern to
make for flexible installation and speaker location. The Legatia L4 has an outstanding extended
frequency response; the usable frequency range of this driver exceeds seven complete octaves of
usable bandwidth on-axis (110 Hz – 18,000+ Hz). Even off-axis, the L4 faithfully recreates more than
five full octaves of information, for the ultimate midrange/full-range driver.
Phase Plug and Shorting Rings
The L4 comes equipped with a phase plug pole piece extension at the center of the cone. The phase
plug is aluminum and, by design, ensures enhancement of the total inductance profile,
providing
much of the inductance reduction benefits noted in this design. The phase plug is anodized black,
which by design does not negatively reduce eddy current, and adds thermal dissipation potential, not
to mention sleek, under-stated cosmetics. The phase plug extends well down inside the pole vent,
and acts as a very large and efficient heatsink for any heat that radiates into the pole. The highest
frequencies of audio emanate from the area around the center of the cone and the lower frequencies
are produced by the area of the cone that is farther from the center. The phase plug pole piece
extension improves the L4’s performance and clarity by deflecting delicate midrange and treble tones
forward of the driver, while minimizing distortion and improving bandwidth.
The L4 uses copper shorting rings. The shorting rings consist of optimally sized and placed rings of
copper (Cu) to create a total inductance profile that is not just low, but flat over stroke, frequency, and
power. Inductance is the number one limiter of high frequency extension and modulation of