User manual JAMO D 8CEN

[. . . ] Remember also that loudspeakers should be broken in, that is play for some time, before they can perform at their best!If you do not want to do this when you are at home, set your tuner between two stations, so that a hissing sound is heard from the loudspeakers. Then leave the loud-speakers to play for a few hours at a medium sound level. After this, the rest is up to you - we are sure that you will get many hours of fine entertainment. [. . . ] The special 1½ midrange dome has been chosen to obtain a sufficiently low crossover frequency between the bass and midrange areas in order to ensure wide horizontal dispersion. This is important to enable the centre loudspeaker to cover a broad listening position, when several persons are listening. With a low crossover frequency, out of phase problems between the two woofers are avoided, allowing the required dispersion to be realised. In order to ensure perfect transition to the woofer, the midrange unit is fitted in a specially designed horn, which has been tuned to just below the resonant frequency of the unit. The horn provides a better coupling between the diaphragm and the surrounding air, which results in a linear reproduction and higher efficiency in the lower midrange area. The diaphragms of the two woofers are manufactured in fibre glass, which is a rigid and quite heavy material. The relatively heavy moving mass and the resulting low resonance frequency have been chosen partly to achieve optimum harmony with the Aperiodic Chamber and partly to obtain the desired powerful and precise reproduction of the bass area below 1000 Hz. This ensures that the magnetic force stays concentrated around the voice coil instead of spreading out into the basket. Also the magnetic strayfield is perfectly controlled, so that the loudspeaker can be placed directly on top of a TV set without causing discoloration of the picture. The unique design was developed not only to please the eye, but equally to satisfy the ear. Jamo D 8SUR is manufactured in 16 mm MDF board and accurately dampened with acoustic foam. The surface of the foam is shaped in a honeycomb pattern to obtain the largest possible surface area and thus maximum dampening of the sound radiating from the rear of the units. To achieve optimum sound reproduction, the designs of the two loudspeakers in a pair are laterally reversed and therefore they are available only in sets of a left and right loudspeaker (see the marking on the back of the loudspeakers). The unit is oil cooled and has a voice coil wound of thermosetting wire on an aluminium voice coil former, for high power handling. Other than the exclusive design, the special weave ensures a uniform material thickness over the entire diaphragm. A loudspeaker diaphragm can be compared to a piston, and to comply with the heavy demands on the diaphragm materials stretch and compression properties, the composite fibre material is composed of four different types of glass and treated with a tough-hardening resin. Combined with the natural rubber suspension, which ef-fectively prevents vibrations from travelling back to the diaphragm, the result is a very well-controlled diaphragm that operates without break-ups in its working range. the units basket is made from injection moulded carbon fibre reinforced ABS. Using a non-magnetic material such as ABS ensures that the magnetic force stays concentrated around the voice coil instead of spreading out into the basket. As a result, the efficiency of the unit is increased, and the loudspeaker may be placed closer to a TV set without risk of discolouring the image. Compared to a conventional metal basket, the acoustic properties are significantly improved, as the ABS material has a much higher internal damping. The unit has a large magnet and a heavy voice coil with a diameter of 25mm. [. . . ] Turn the terminal screws counterclockwise until the twisted wires can easily be inserted into the holes. NOTE: Verify that the wires from the + and - cables do not touch each other, as a short-circuit could damage the amplifiers output stage. If you wish to connect each speaker with a single cable, the supplied bridges should remain fitted between the two sets of terminals. The loudspeaker comes from Jamo with the bridges fitted for single-wiring. [. . . ]