JBL DD66000CH-EVEREST II [DD66000CH], User Manual

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Project Everest DD66000
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045Be-1 Ultrahigh-Frequency Compression Driver and Bi-Radial Horn
Like the original 045Be, the 045Be-1 uses a 1-inch (25mm) beryllium
diaphragm and 2-inch (50mm) neodymium magnetic structure. The pure-
beryllium diaphragm is less than 0.04mm thick and has a mass of only 0.1
gram. The single-layer aluminum-ribbon voice coil is wound without a former
and is attached directly to the diaphragm. The driver employs the smallest
annular-slit phasing plug that JBL has ever designed. The 045Be-1 has been
designed to improve manufacturing yield and consistency. Small changes have
been made to the top plate and some significant improvements were made to
the surround shape and clamping methodology. As a result, the driver has
picked up nearly 5dB of increased output above 30kHz. A section view of the
045Be-1 driver is shown in Figure 4.
Figure 4 – 045Be-1 section view
The extremely low mass of the moving system, high magnetic flux density and
high rigidity of beryllium produce response that is very smooth from below
8kHz to beyond 50kHz.
The response curve has a slight downhill tilt, due to the constant-directivity
nature of the horn used in this system. The Bi-Radial horn is properly scaled to
maintain a coverage angle of 60 degrees in the horizontal plane and 30 degrees
in the vertical plane over the frequency interval from 10kHz to 50kHz.