JBL Synthesis K2 S9900 User Manual
Page 19
Project K2 S9900
19
Internal Crossover Network
The circuit topology, combined with the acoustic behavior of the 1500AL-1 and
476Mg, provides a 24dB-per-octave transition at 900Hz. This is the primary
crossover point of the system. Additionally, the 045Be-1 is turned on above
15kHz to provide extended response to beyond 50kHz.
All of the electrical components are of the highest quality and exhibit the
lowest internal loss. The inductors used are “air core” so as not to introduce
nonlinear hysteresis effects. Capacitors are constructed using polypropylene foil,
which is known for having minimal distortion caused by dielectric absorption
nonlinearities. The low-, high- and ultrahigh-frequency networks employ battery
bias to operate the capacitors effectively in a Class A mode. Every attempt
is made to present as smooth a system impedance as possible to the driving
amplifier. This design element is often overlooked in many loudspeaker
systems, yet amplifiers work their best when they are given smooth, level
load impedance in which to deliver current (Fig. 7).
Figure 7. K2 S9900 system impedance.
The aggregate of these attributes allows the K2 S9900 system to translate
the electrical signal from source material into an accurate and unencumbered
three-dimensional sound field. The system can do this at any desired listening
level, from whisper-quiet to big-band loud, while at the same time maintaining
unchanged acoustic characteristics.