JBL News
Traditionally, large-format mon-itors are found in the controlrooms of purpose-built pro-duction facilities with the requiredinfrastructure and budget. While thesesystems vary in accuracy, they are con-sistent in their ability to provide highdynamic range, extended frequencyresponse and a listening experiencenot possible using small close-fieldspeakers. And while today’s variedproduction spaces would appreciatethe “big” sound monitoring experi-ence, it has not been feasible dueto acoustic, structural and budgetarylimitations. There is a need for a sys-tem that bridges the gap between tra-ditional soffit-mounted systems andnear-fields.In post-production, an increas-ing portion of the work is being ac-complished in a range of spaces, out-side the dubbing theater. While newsmaller rooms have the same dynamicrange requirement as the dubbingtheater, full-sized screen channelspeakers are too large and near-fieldmonitors are too small.At Winter NAMM 2013, JBL Pro-fessional unveiled its new flagshiplarge-format M2 Master ReferenceMonitor. In developing the M2, JBLsought to make large-format mon-itoring a viable option for a broadrange of production spaces. To makethis possible, the system had to meetthese criteria: high output, extend-ed yet neutral frequency response;compact footprint to allow a broadrange of placements; and tune-able tooptimize the interface of the systemto the room. On top of all this, andmost important, the listening experi-ence had to be compelling, engagingand enjoyable. With these objectivesin mind, JBL set out to develop thefirst complete solution for music fa-cilities ready to move up from near-fields, and for post rooms in need ofspeakers that bridge the gap betweennear-fields and large-format cinemasystems.The M2 is a free-standing, 2-way systemthat can be placed in anyenvironment to providean exceptionally accuratemonitoring experience.Leveraging a new gen-eration of JBL high-out-put, ultra-low distortiontransducers, the M2 pro-vides in-room frequencyresponse of 20 Hz to 40kHz with 123 dB maxi-mum SPL.To achieve these ob-jectives, ground-up innovation was re-quired, and the system incorporatescomponents with a total of seven pat-ents and one pending. So, how didthey get there? In January 2012, JBLintroduced its next-generation VTXline array series, incorporating a revo-lutionary high-frequency device, theD2 Dual-Diaphragm Dual-Voice-CoilDriver. The patented D2 overcomesthe limitations of conventional com-pression-driver technology: limitedhigh-frequency extension due to massof the diaphragm and voice coil, anddistortion characteristics that arise dueto dome breakup modes. The resultis a device that delivers dramaticallysuperior high-frequency response. Re-placing the conventional dome designwith annular diaphragms, D2 dual-driver design allows the M2 to meetseemingly opposing objectives: extend-ed high frequency, very low distortionand very high output and eliminatesthe need for separate mid- and high-frequency drivers.Based on measurements and posi-tive results in subjective evaluations,the D2 would meet those objectivesand now JBL needed a single 15-inchwoofer capable of very high output,very low distortion and reach to20Hz. The M2’s 2216Nd DifferentialDrive Woofer employs no less thanfive patented technologies to reducepower compression that is detrimen-tal to a system’s low frequency per-formance. Echoing the “dual driver”design of the D2, the 2216Nd utilizesdual neodymium magnets and twovoice coils and special wire that al-lows the woofer to maintain constantimpedance regardless of output.With the D2 and 2216Nd as theM2 engines, JBL could achieve veryhigh output and extended frequencyresponse in a relatively compact two-way design. But the key to systemaccuracy and sound stage is acousticintegration of the two and their in-terface to the environment. While theD2 driver provides the efficiency forgreater output and listening distanc-es, conventional horndesigns suffer from lim-itations: high frequen-cy tends to be beamyand off-axis response,responsible for the“blend” in the room, isnot neutral. JBL engi-neers had been work-ing on a revolutionaryhorn design that over-came these limitations.The M2’s patent-pending ImageControl waveguide enables neutralfrequency response, not just on-axis,but off-axis in the vertical and hori-zontal planes, all the way down tothe M2’s 800 Hz crossover point andan imperceptible transition betweenthe two drivers. The unique geometryof this waveguide allows the M2 todeliver remarkable high frequencydetail, soundstage, and natural bal-ance at nearly any listening positionin a broad range of acoustic environ-ments. Since design of this complex-ity and level of detail is an iterativeprocess, JBL performs Finite ElementAnalysis, creating virtual simulationsof off-axis response, pattern control,and the blend of the high frequencydriver and woofer. Rapid prototyp-ing equipment allows JBL to quicklyproduce physical samples of eachiteration, and verify the success ofthe design through measurement andsubjective evaluation.While some free-standing largemonitor systems exist, the sound andaccuracy varies from room to room.For the past 15 years, JBL’s studiomonitor line has revolved around itsproprietary Linear Spatial Reference(LSR) design, responsible for theM2’s ability to provide a consistentlyaccurate and neutral monitoring ex-perience in a broad range of rooms.For sound arriving at the mix po-sition to be smooth and neutral, itis not enough for a speaker to mea-sure “flat” on-axis—it is essential thatthe speaker have excellent off-axisperformance. While other manufac-turers use a single on-axis frequency responsemeasurement taken atone point in space, JBLmeasures monitor sys-tems over a sphere thatencompasses all powerradiated into the listeningroom—in every direction.This data reflects 1,296times the information ofa single on-axis responsecurve. Seventy-two mea-surements of the directsound field, the reflect-ed sound field, and thereverberant field—the entire soundfield heard by the listener—are cor-related to optimize response at thelistening position.The system is completed by Har-man Crown I-Tech amplifiers, whichnot only power the M2 system, butalso provide the floating point digi-tal signal processing for the systemcross-over. The Crown-powered M2system includes all the EQ needed fordetailed room-tuning, and offers theability to store multiple EQ curvesto meet the needs of the applicationor client preference. Harman HiQnetSystem Architect software is includedto provide external control of sys-tem EQ and tuning capabilities. Usedin conjunction with external mea-surement hardware and software, theroom EQ ensures a high degree of ac-curacy whether the monitors are free-standing, soffit-mounted, or placedadjacent to a wall.While the M2 provides the out-put and the resolution needed fordemanding remix applications, itscompact 14 x 20-inch footprint al-lows placement flexibility in smallerrooms. Used as screen channels, theM2 integrates perfectly into multi-channel systems with JBL cinemasurrounds, subwoofers and overheadsurround speakers specified in bur-geoning 3-D audio formats. Selectmodels in the BSS Soundweb Lon-don processor line can be fitted withdigital inputs and externally synchro-nized to house word-clock for an all-digital signal path. Centralized man-agement of EQ presets allows storageand easy recall of curves such as theX-Curve for specialized applications.With a compact form factor, flex-ible placement options, tune-ability,and an integrated system approach,the M2 eliminates the impedimentsthat have prevented personal-use stu-dios from having the big, world-classmonitoring experience, and for smalland medium size remix rooms a reli-able translation to the large stage.JBL Professionaljblpro.comPeter Chaikin serves JBL Professional asDirector, Recording and Broadcast.Decades In Experience, SummedJBL M2 MASTER REFERENCE MONITOR[April 2013]
