User manual JBL GHE1200V

[. . . ] 1 For the best audio stereo reproduction, the two loudspeaker systems should be an equal distance from your listening position and separated so that the angle between them, at the listening position, is between 40 and 60 degrees (see Fig. For example, if your listening position is 8 to 12 feet (2. 5 to 4 m) from each speaker, the two systems should be about 8 feet (2. 5 m) apart. Placing the loudspeakers in corners or against a wall will result in the strongest (not necessarily the most accurate) bass. [. . . ] 3 Hooking Up Multiple Sets of Speakers If your receiver has two complete sets of speaker terminals ("A" and "B"), it's possible to hook up an additional pair of speakers for simultaneous sound in another room. However, some speakers may not be usable as a second pair if you want to play two sets at once. Before hooking up another set of speakers besides your GHE Series, check the following: 1. Impedance is always expressed in ohms and can be found in the owner's manual that came with your unit. For example, the following are typical entries in receiver/amplifier owner's manuals: A)100 watts RMS into 8 ohms, both channels driven, 20­20kHz with less than 0. 02% THD. B) 160 watts RMS into 4 ohms, both channels driven, 20­20kHz with less than 0. 02% THD. A pair of GHE Series speakers when combined with another pair of 8 ohm speakers will present an impedance to the receiver/amplifier that is approximately 4 ohms. This speaker combination can be used with the receiver/ amplifier cited in B above. If the receiver/ amplifier has a specification similar to that shown in A above, or if your second set of speakers has an impedance other than 8 ohms, you must consult the receiver/ amplifier manufacturer for clarification. Amplifier Flexibility Bi-wiring also allows you the option of using separate stereo power amplifiers for your left and right speakers. 5) can not only add sonic improvements but upgrade convenience as well. From a sound standpoint, dual amplifiers reduce intermodulation between left and right channels, since a complete set of input and power supply circuits are devoted to each speaker. Dual amps also provide an easy power upgrade path: you can start out with one stereo amplifier then add a second one later to quadruple power reserves. BI-WIRING Caution: Before attempting a Bi-Wire hook-up, take a few minutes to read through this section and follow the instructions carefully. The GHE Series speaker terminals are designed so that separate sets of speaker cable can be attached to the woofer (LF) and midrange/ treble (HF) portions of the crossover network. Bi-wiring can provide several sonic advantages and considerably more flexibility in power amplifier selection. Reduction of Intermodulation The majority of current flowing between an amplifier and speaker is devoted to the reproduction of bass. In fact, 60% or more of an amp's power is destined for the woofers. When current flows through a wire, it produces a magnetic field (EMF) which expands and collapses at a rate equal to that of the music's complex frequency components. If a single speaker wire must conduct the full musical frequency spectrum, this preponderance of low frequency information can interact with or modulate high frequencies. The resulting intermodulation can create audible changes to treble even before it reaches your loudspeakers. 4 ­ One Amp Bi-Wire. PREAMP w/Y-corded output HF LF STEREO AMPS HF LF Fig. [. . . ] The polarity (+&­) of one speaker has been reversed relative to the other. If you are still encountering problems, consult your JBL dealer. GENERAL CARE The grille is held in place by pins near the edges. To remove the grille, grasp it by both top and bottom edges and pull gently. [. . . ]