JBL Project K2 S5500

Commentary

The Project K2 series tall boy type speaker system was developed with the sound quality concept and the latest technology that produced the S9500.

The S5500 adopts a virtual coaxial 2-way unit configuration with a middle and high range unit placed in the center.

Two 30 cm cone type woofer LE125S are installed in the low range.
This unit uses a strong magnetic circuit that inherits the technology of S9500 after examining the sound quality balance with the compression driver 275 nd in detail. The voice coil is a 3-inch large-diameter type with an aluminum ribbon wound edgewise. The diaphragm is made of high-rigidity cone paper coated with JBl's unique coating material, Aqua Plus, which provides excellent low-frequency characteristics.
In addition, a Center vented pole piece with a ventilation hole in the center of the pole piece and an aluminum die-cast heat sink cover the entire magnetic circuit to cope with heat generation from the voice coil.

A horn type unit consisting of a 275 nd compression driver and a biradial horn is mounted in the high range.
The 275 nd is a scaled down version of the 475 nd. The 275 nd has a pure titanium diaphragm 2 inches in diameter and 0.05 mm thick coated with JBL's original Aqua Plus to control the high-frequency response while reducing unnecessary split vibration. In addition, the linearity has been improved by adopting diamond edge suspension.
An internal magnetic structure using neodymium magnet for the magnetic circuit is adopted, and anti-magnetic measures are also perfect.

A new material named JBL COMPII is used for the biradial horn.
This material is based on polyester and made for space development and military use. In addition to less resonance, the density is approximately 2.5 times higher than that of MDF material. This material excellent characteristics as a material of horn.
The directional characteristics of this horn are 60 degrees in the horizontal direction and 40 degrees in the vertical direction. This horn is relatively narrow without requiring the directional characteristics and pursues clear presentation of the sound image and natural sound field expression.

A charge-coupled linear definition system is adopted for the network.
This method was derived from the analysis of the operation state of the capacitor in the network circuit which had been overlooked in the past. A pair of capacitors with twice the capacity of the normal capacitor is used in the network circuit. By applying a bias voltage from the built-in battery to the center point of the pair, the operating range of the capacitor is shifted to a level with excellent linearity, thereby suppressing the 0 cross distortion that occurs when the polarity of the capacitor is reversed.
Monster cable is used for internal wiring.

- 1 db, 0 db and + 1 db high-frequency output level adjustment switches are provided for fine adjustment according to the sound characteristics and listening point of the listening room.

Although the enclosure is integrated in appearance, structurally, each unit is contained in a separate enclosure.
The woofer enclosure basically operates as a bass reflex using a pipe duct. However, in the design, JBL has developed a new method called Imaginary Equivalent Tuning (IET). By changing the volume of the two upper and lower enclosures and the resonance frequency of the duct, we pursue the optimum phase characteristics and sound pressure level in the low frequency range when playing music. By this, we can obtain flat frequency characteristics while minimizing phase disturbance.

The input terminal can be used for bi-wiring connection, and there is also a switch for disconnecting the built-in network so that multi-amplifier drive using an external network is also possible.

The S5500 comes in four color variations : black high-gloss lacquer, Juglans californica, マドローンバール, and gray birds eye maple.

Model Rating

Method	2-Way, 3-Speaker, Bass Reflex System, Tall Boy Type
Units, etc.	For Low Band : 30 cm Cone Type (LE125S) x2 For High Frequency : Horn Type (275 nd)
Frequency characteristic	35 Hz to 20 kHz -6dB 48 Hz to 18 kHz ± 2 dB
Output sound pressure level	95dB/2.83V/m
Nominal input impedance	4 Ω
Maximum allowable input	150W(I.E.C Shaped noise)
Horn directional characteristic	Horizontal 60 ° x Vertical 40 °
Crossover frequency	800Hz(-18dB/oct)
External dimensions	Width 499x Height 1,254x Depth 412 mm
Weight	89kg