JBL LSR Owner's Manual

Contents

6Section 3. - LSR32 GENERAL OPERATION3.0 Basic IntroductionThe LSR32 Linear Spatial Reference Studio Monitor combines JBL’s latest in transducer and systemtechnology with recent breakthroughs in psychoacoustic research to provide a more accurate studio reference.The neodymium 12" woofer is based on JBL’s patented Differential Drive® technology. With theneodymium structure and dual drive coils, power compression is kept to a minimum to reduce spectral shift aspower levels increase. An added third coil between the drive coils acts as a dynamic brake to limit excess excur-sion and reduce audible distortion at the highest levels. The cone is made of a carbon fiber composite forminga rigid piston supported by a soft butyl rubber surround.The midrange is a 2" neodymium magnet structure with a woven 5" Kevlar cone. The powerfulmotor structure was chosen to support the low crossover point to the woofer. In order to achieve the goal ofaccurate spatial response, the crossover points are located at 250 Hz and 2.2 kHz. These transition points werechosen to match the directivity characteristics of the three transducers.The high frequency device is a 1" composite diaphragm integrated with an Elliptical Oblate Spher-oidal (EOS) Waveguide with 100 x 60 degree dispersion which is critical to the smooth spatial responserequired in today’s working environments. The Mid and High devices are mounted within millimeters of eachother on a cast aluminum sub-baffle that can be rotated for horizontal or vertical placement. This allows max-imum flexibility in placement to reduce console and ceiling splash that destabilizes imaging and depth.The crossover filters are optimized to yield 4th-order (24 dB/octave) Linkwitz-Riley electroacousticresponses from each transducer (in phase; -6 dB at crossover). In order to achieve optimal symmetricalresponse in the vertical plane, both magnitude and phase compensation are implemented in the crossover net-work. The crossover network allows the user to adjust the high frequency level above 3 kHz. This allows the lis-tener to compensate for effects of near-field or mid-field spectral balance or differing amounts of high frequen-cy absorption. Components used in the crossover are exclusively low-loss metal film capacitors; low distortionelectrolytic capacitors; high-Q, high saturation current inductors and high current sand cast power resistors.3.1 Audio Connections:The LSR32 is equipped with two pair of 5-way binding posts. The lower pair feed the woofer and thetop pair feed the mid and high frequency elements. The connectors are designed to accept up to 10 AWG barewire. Spacing of the two input terminal pairs allows use of standard Dual Banana jacks. The two pairs are nor-mally connected together with metal shorting bars. This allows either pair to be used in normal operation.Alternative cabling possibilities include bi-wiring and passive bi-amping or using both terminals to get more“copper” from the amp to the speaker. Positive voltage to the “Red” (+) terminal will produce a forwardmotion in the low frequency cone.