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Aiming For Accuracy

In August, JBL Professional introduced its 3 Series powered studio monitors, with the goal of delivering a new level of performance and accuracy to the market at price points lower than those of any existing JBL studio monitors.

The JBL 3 Series line consists of the LSR305 and LSR308 internally bi-amplified studio monitors with 5-inch and 8-inch low frequency drivers respectively, and 1-inch dome high-frequency drivers. In August, JBL Professional introduced its 3 Series powered studio monitors, with the goal of delivering a new level of performance and accuracy to the market at price points lower than those of any existing JBL studio monitors.

The Development Process

At JBL, development is always in process. Since JBL serves virtually all market segments and applications with speakers, when new solutions in the transducer, acoustics and electronics domain come onto the scene in one JBL segment, they may be attractive for additional applications. It wasn’t until a number of elements came into alignment that we had everything needed to start development and set the delivery date for a new line of most affordable studio monitors.

The 3 Series line is targeted to fill the needs of a very broad segment of the market that includes music recording hobbyists, professional video-post and broadcast facilities in need of an affordable reference monitor. From JBL’s perspective, “affordable” can’t mean “inaccurate.” There is a great sense of responsibility that comes with designing a reference monitor. Music producers, post-production customers and broadcasters rely on our speakers to produce program material that sounds good outside the control room. When someone uses any of our monitors, we’re “packing their parachute” for them. Our philosophy is, and the result of good acoustic design should be, whether you use our top-of-the-line speaker or our low-cost model, you’ll get the same mix. Of course at the higher price points, the monitor delivers greater resolution, higher output and lower distortion, but the balances of the mix are the same. A mix created on one model sounds “right” on all the others regardless of price. While developing a flagship reference monitor with jaw-dropping performance pushes the limits of physics and the engineering staff, producing an affordable monitor worthy of professional projects is also tremendously challenging.

Design Objectives

The entry-level price segment of the studio monitor market is dense with powered models of varying quality from many manufacturers. We wanted to make a real difference at this price point and we wanted the benefits to be clearly audible. Factoring in manufacturing costs, overhead and margin, the budget for the woofer, tweeter, electronics and enclosure is very tight. Just getting in the game requires a careful balancing act: Don’t slight the budget for the transducers, yet make sure your amps have enough output to achieve reasonable volumes. Fortunately at JBL, our core expertise is in transducer technology and we were able to develop transducers with really good performance at reasonable cost to meet 3 Series cost targets. Using a new class D amplifier solution eliminated the need for a large heat sink, resulting in some cost reduction. While these parts (coupled with a carefully designed crossover) got us in the game, we found the greatest opportunity for audible improvement in the area of directivity and imaging. It is not just the on-axis frequency response, but off-axis component that contributes to a monitor’s accuracy and ultimately the speaker’s imaging. In this domain, a winning solution hinges on great engineering and acoustic expertise rather than parts cost alone.

Enabling Technologies

This graph shows measurements of one LSR308 Studio Monitor and an identically-priced “speaker B” made at 10 degree increments from a point directly on-axis to a point 90 degrees off axis. The on-axis response of speaker B is not neutral and the off-axis frequency response deteriorates progressively with each measurement. In comparison, JBL describes the LSR308 response as “free of dramatic peaks and dips.” In January of 2013, we introduced the M2 Master Reference Monitor, a large flagship studio monitor showcasing JBL’s next-generation transducers. The system represents a lot of R&D, recognized with seven patents and two pending. The M2 project was our “space program” out of which new technologies and disciplines emerged that could be leveraged in future projects. The 3 Series models share M2’s patent-pending waveguide technology. The distinctive Image Control Waveguide is responsible for the excellent imaging and accuracy customers are responding to in the market.

JBL has long employed waveguide technology to achieve greater accuracy in the room. A properly designed waveguide surrounding the high-frequency transducer controls acoustic energy to (1) match its directivity to that of the woofer at the crossover point, and (2) ensure high-frequency energy is neutral off-axis as well as on-axis. A properly designed waveguide is the product of a complex mathematical formula. Rapid prototyping equipment at JBL allows us to evaluate many iterations of a waveguide design, allowing our engineers to perfect the design and not settle for “good enough.” The Image Control Waveguide used in the 3 Series is a very sophisticated piece of engineering. The curvature of the waveguide allows the directivity of the sound in the vertical, horizontal and oblique planes to be uniform. JBL engineer Charles Sprinkle designed the M2 and 3 Series waveguides based on the size and position of the drivers in each monitor and their crossover frequencies. The result is a seamless transition between high and low-frequency drivers and uniform directivity throughout the bandwidth. Small ridges in the throat of the waveguide serve to diffuse very high frequencies. Sound exiting the high-frequency driver clings to the waveguide, hits these ridges, and spreads so subtle high-frequency detail and micro-dynamics are heard at the listening position. An immediately evident benefit of the waveguide is the audible depth and strong phantom center heard in the stereo panorama, caused by optimized summing of energy produced by a stereo pair of speakers. The Image Control Waveguide demonstrates (as confirmed by customers) that when the speaker is telling the same story in every direction, magic happens.

The JBL 3 Series line consists of the LSR305 and LSR308 internally bi-amplified studio monitors with 5-inch and 8-inch low frequency drivers respectively, and 1-inch dome high-frequency drivers. While high-quality parts got us in the game, the positive response to the 3 Series line demonstrates success is contingent the attention we paid to directivity.

Peter Chaikin serves JBL Professional as Senior Manager, Recording and Broadcast Marketing.

JBL Professional
jblpro.com

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