The JBL LSR6312SP powered studio subwoofer is designed to provide low frequency extension and sophisticated bass management capabilities in stereo and multi-channel applications where exceptional spectral accuracy and high-SPL are required. The system includes JBL's RMC Room Mode Correction circuit. The system is designed around JBL's 252F LF transducer, which uses dual voice coils and a powerful neodymium magnet. With the patented Differential Drive technology, power compression is kept to a minimum. An additional third coil located between the two drive coils acts as a dynamic brake to limit excess excursion and reduce audible distortion at the highest operating levels. The cone is made of a carbon fiber polypropylene composite forming a rigid piston area supported by a soft butyl rubber surround. A 260-watt continuous power amplifier is integrated into the LSR6312SP system and provides correct drive levels for optimized frequency response. Amplification is class A-B in an all discrete topology.
The subwoofer derives its input by summing Left, Center, Right and Direct LFE inputs. Subwoofer signals can be selectively derived from the front channels or from the Direct input alone using a simple Remote Bypass contact closure switch. User-selectable settings are provided for -10 dBV, +4 and +8 dBu sensitivity. For calibration and level matching of the system, an Input Trim control can be inserted into the circuit for continuously variable attenuation of the system input. Additionally, the Direct input has a dedicated Input Trim. The LSR6312SP includes Left, Center and Right channel outputs to feed external satellite speakers. The LCR outputs are high-passed at 80 Hz.A ¬" jack allows connection of a Remote LCR Bypass contact closure switch. When the switch is used, full-range signals are sent to the Left, Center and Right satellite speakers and the subwoofer derives its feed from the Direct input only.
The LSR6312SP includes JBL's exclusive RMC Room Mode Compensation circuitry for final matching of the system response to the room's acoustics. RMC consists of a single parametric cut-only equalizer that is individually tuned to attenuate to the dominant room mode peak in the system's response, thus making the overall room response linear. A kit including a small sound level meter, test CD and a Q template, and a remote bypass switch accompanies each system. Switch 6 defeats the RMC function. The remote bypass switch is connected to the LSR6312SP RMC remote bypass 1/4 inch jack via a 2-conductor cable.