Linear Spatial Reference Technology (LSR)
Building blocks to clear sound.
The Linear Spatial Reference (LSR) philosophy is based on a set of design goals that carefully control the overall performance of the system in a variety of acoustic spaces. Instead of focusing on a simple measurement such as on-axis frequency response, JBL measures systems in a field 360 degrees around the speaker and engineers the entire system to ensure off-axis response reflected to the mix position is also smooth and accurate. JBL defines the ultimate performance specification for new systems – what it will sound like in your room. At the mix position, you hear a combination of direct sound and sound reflected from the rooms surfaces. For sound arriving at the mix position to be smooth and neutral, it is not enough for a speaker to measure “flat” on-axis - it is essential the speaker have excellent off-axisperformance. 

While other manufacturers use a single on-axis frequency response measurement taken at one point in space, JBL measures monitor systems over a sphere that encompasses all power radiated into the listening room – in every direction. This data reflects 1296 times the information of a single on-axis response curve. Seventy-two measurements of the direct sound field, the reflected sound field, and the reverberant field, the entire sound field heard by the listener, is correlated to optimize response at the listening position. In place of spectral smoothing used by some manufacturers, which actually conceals data, the JBL approach actually exposes flaws in systems, such as resonances, poor dispersion and other causes of off-axis coloration. The data shown below is a set of spatially measured graphs that are the heart of JBL’s philosophy.

The JBL Tradition Continues
The anechoic chamber is an essential tool for performance measurement. Without it, all you can do is predict. While anechoic chambers are very expensive and some manufacturers have none of their own, JBL has many anechoic chambers on its campus. Since position in the room influences the perception of the speaker, critical A/B comparison evaluations require that every speaker being judged is positioned in exactly the same spot in the room. Since no solution exists which allows rapid swapping of pairs of speakers, JBL manufactured the only known Speaker Shuffler, a computer-operated device capable of physically swapping pairs of speakers in the space of 3 seconds. JBL’s technical staff is second-to-none. Our engineers are respected by their peers in the industry and have won technical awards and honors from the Academy of Motion Pictures Arts and Sciences and from the Audio Engineering Society for designs which have advanced the professional audio industry.