User manual JBL S3SR

[. . . ] JBL Consumer Products, Incorporated 240 Crossways Park West Woodbury, NY 11797 8500 Balboa Boulevard Northridge, CA 91329 800-645-7484 A Harman International Company P/N 301227-001 ® SYNTHESIS THREE SPEAKERS OWNER'S MANUAL CONTENTS INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 SPEAKER PLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 CONNECTING THE SPEAKERS TO THE REST OF YOUR SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 FINE TUNING YOUR AUDIO SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1 INTRODUCTION Congratulations on purchasing this JBL Synthesis Three home theater speaker. This product represents the synthesis of everything that JBL has learned about the emotional power of audio and video in over fifty years of preeminence in the field. It sets new benchmarks in the use of "high technology" and provides you with the experience of being in some of the world's greatest movie-houses and concert halls, right at home!JBL's Synthesis Three speaker systems feature the following: THX ® LICENSED HOME AUDIO SYSTEM: When used with a Home THX controller and amplifiers, your speaker system will deliver state-of-the-art THX home theater experience to your home. [. . . ] When you can see any of the front speakers reflected in the mirror, mark the wall at the mirror for later placement of absorptive material. A variation of this method is especially helpful in rooms which are already fairly "dead" acoustically. Rather than using absorptive material in rooms like these, try using diffusion instead. 9 Commercially built diffusers are available but large bookcases and irregularly shaped furniture will also serve the same purpose. They reflect sounds in a highly randomized way which effectively "scatters" the sound in all directions. Place the diffuser where you would otherwise place the absorptive material (using the "mirror trick"), to break up the first early reflections and scatter them randomly throughout the room. Commercially available fiberglass, foam and diffusion panels may not be aesthetically acceptable in many installations, particularly when the home theatre room serves multiple purposes. All of these materials can be covered with acoustically-transparent cloth for design considerations. It is important that the cloth be acoustically transparent, however, or else the effectiveness of the absorptive material will be greatly reduced. The simplest test for this is to hold a large sample of the cloth in front of a speaker playing the pink noise found in Chapter 6 of the WOW!If you can move the cloth in front of the speaker without hearing a difference, you are all set. Large expanses of glass can be challenging. They reflect mids and highs but often pass bass through almost as though they didn't exist. The result is a characteristically bright, rough sound which can be difficult to correct electronically. The best treatment is generally the heaviest insulated drapes which can be found. (Incidentally, these serve double duty, controlling light which might otherwise fall on the screen. ) The materials just discussed are ineffective at lower frequencies. See the discussion on Standing Waves for more information about treating environments with low frequency response problems. EXCESSIVE USE OF ABSORPTIVE MATERIALS People are sometimes tempted to go overboard with absorptive material once they discover how powerful its use can be. While the ideal home theatre should be considerably "deader" acoustically than a typical living room, it still needs some reflectivity and diffusion. ROOM ABSORPTION FOR HOME THEATRE SYSTEMS Surround speaker Screen speaker · "Dead" zone absorbs front speaker reflection. · "Live" zone provides surround propagation Reflective "live" zone Absorptive "dead" zone 10 In particular, the surround speakers depend on non-absorptive surfaces for their operation, since they radiate virtually no sound directly at the listeners. The best arrangement of the absorptive and non-absorptive surfaces in the room can be seen in the diagram below. Most of the room surfaces are relatively absorptive, with the notable exception of the rear wall and the highest portions of the other walls, which should be diffusive. "SLAP" ECHOES "Slap" echoes are common in rooms which have parallel walls with little or no absorption or diffusion. [. . . ] Leave yourself some latitude with regard to subwoofer placement when planning your system--the final adjustment will probably have to be done on something of a trial-and-error basis. STANDING WAVE SOLUTIONS: ABSORPTION In theory, it is possible to damp standing waves with absorptive material. The difficulty is that the thickness of the absorptive material would have to be approximately one-half the wavelength of the lowest frequency requiring damping. This means a five-foot thickness of fiberglass would be required in order to damp everything down to 100 Hz--not very practical. [. . . ]