JBL Project EVEREST DD66000 User Manual page 13

Project EVEREST DD66000
These features, when taken as a whole, create a new large format compression
driver with the greatest high frequency extension, lowest distortion, smoothest
response and greatest sonic detail.
045Be-1 Ultra-High Frequency Compression Driver and Horn
Like the 045Be, the 045Be -1 uses a 25-mm beryllium diaphragm and 50-mm
neodymium magnetic structure. The pure beryllium diaphragm is less than 0.04
mm thick and has a mass of only 0.1 gram. The single layer aluminum ribbon
voice coil is wound without a former and attached directly to the diaphragm.
The driver employs the smallest annular slit phasing plug that JBL has ever
designed. The 045Be-1 has been redesigned 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 5 dB of increased
output above 30 kHz. 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
the high rigidity of beryllium produce response that is very smooth from below
8 kHz to beyond 50 kHz.
The response curve has a slight down hill tilt due to the constant directivity
nature of the horn used in this system. The 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 10 kHz to 50 kHz.