The JET tweeter, developed to perfection on the basis of the famous "Air Motion Transformer" by loudspeaker pioneer Dr. Oskar Heil. Its principle: a concertinaed foil membrane is driven by a strong magnet system of neodymium rods. This "motor" drives the air considerably faster than the conventional pistonic technique. High sensitivity and extraordinary dynamics are the result.

The tweeter's membrane and the coil are one piece thus the efficiency of the whole system is dramatically increased: there is no more energy loss at the joining between the wire coil and the dome – the two move exactly the same instant the current passes through the coil and this results in a better performance.

The custom built folded foil diaphragm sets the JET tweeters fundamentally apart from all conventional tweeters. The lamellar drive "breathes“ the air in and out. The result: ultra smooth treble with stunning transparency.

JET III - How it works?

Current through the membrane 2 causes it to move left and right in magnetic field 6, moving air in and out along directions 8; barriers 4 prevent air from moving in unintended directions.

The diaphragm pushes back and forward from itself in a similar physical motion pattern to what is observed when an accordion is squeezed in and out to pump air though the reed chambers, albeit over an exceedingly smaller motion range.

The result is a dipole driver with an extraordinarily rapid response rate, caused both by the extremely low mass of the polyester driver, and by the far smaller motion range it undergoes on each “swing” compared to a dynamic driver. In this technical respect, it shares characteristics with the electrostatic driver.

The discernible motion of each of these diaphragm flexes is very small, but because of the folded structure more air is moved than would be by a conventional cone or electrostatic driver of the same plotted surface area. As a matter of surface comparison, a standard one-inch-wide AMT strip has a functional driver area which is comparable to a circle-shaped dynamic cone with a diameter of eight inches. The folded driver design, combined with the small motive range, means that the AMT acts like a point source version of a larger driver, inherently resulting in lower distortion in sound reproduction. As a result of its motion pattern, the AMT "spits" the air out in a way which is compatible with what happens when, although you apply only a small amount of pressure to a slice of fruit, the pip inside shoots out at high speed. The motion of the air as it leaves the diaphragm is in fact around five times faster than the motion of the actual driver structure. Hence the name Air Motion Transformer.

• Further details: http://en.wikipedia.org/wiki/Air_Motion_Transformer

"ELAC's signature JET tweeter is their advanced development of Dr. Heil's Air Motion Transformer, a transducer without conventional voice coil assembly. A heavily folded Kapton foil membrane sports a chemically bonded aluminum layer etched into which is a quasi voice coil. 0.84mm wide, this driver operates like an accordion, squeezing air out of its folds at high velocities, albeit with the mechanical motion -- and this is the trick -- not in the direction of the listener but crosswise. This concept displaces a lot of air with minimal effort to explain the general claims for high dynamics and good efficiency with AMTs." Full version: April 2008 issue of fairaudio.de .

"The beauty of Heil`s system is that because the 'pleats'in the membrane are highly efficient, the motor system has neither to be large nor high-powered. Also because the pleated membrane is inherently 'loose', its resonant frequency is well outside its operating range – something that can't be said of any dome tweeter ... ELAC calls its version a 'JET' tweeter." From the "Hi-fi and home theatre technology" magazine (Australia) review on FS 207.2 floorstander: http://www.elac.eu/dbs/tests/2006/060204.html .

JET III used in:
	BS 182 , BS 184, FS 187, FS 189
	BS 203 A, FS 207 A
	BS 133 JET, FS 137 JET, FS 210 CE, Spirit of Music CE
	BS 243, BS 243 Limited Edition , BS 253, BS 244, FS 247, FS 247 Sapphire Edition, FS 248, FS 249
	BS 243 BE, BS 244 BE, FS 247 BE, FS 248 BE, FS 249 BE
	BS 253, FS 257
	305 CE, 310 CE, 310 Indies Black, 330 CE
	FS 509 VX-JET
	607 CE, 607 4PI CE, 609 CE

The 4Pi tweeter was developed by ELAC and members of the Dutch Van den Hul/Bakker group in 1984. The patented 4Pi tweeter became a symbol of high-quality tweeter reproduction.

ELACs engineers designed a new version of drivers for the 600 series!

ELAC 4Pi sectional view

The principle of the 360 degree omni-directional tweeter:

A 0.006mm aluminium ribbon tweeter forms a leight-weight diaphragm that provides excellent impulse reproduction. Moving coils that increase the oscillating mass of conventional tweeters and create impulses for reproduction are not essential anymore. The sawtooth-shaped ribbon reinforces the diaphragm and enables increased mobility at higher levels. In comparison to previous models, the arrangement of new neodymium rings create a field of force that provides three times higher efficiency ( + 5 dB) of more than 90 dB/ 2.8 V/m.

The 4Pi tweeter starts off at 4kHz – it yields a resonance-free cut-off frequency of 53kHz and makes this loudspeaker an ideal component for the reproduction of SACD and DVD-A.

The 4Pi technology creates homogenous radiation of high frequencies and offers homogenous sound propagation. Precise imaging and a 360 degree omni-directional sound radiation pattern results in an enlarged actual listening area.

"Transparency and image placement were both improved, while the tonality and harmonics of mid and high-frequencies were both significantly better. Percussion detail was more natural, the nature of the instrument more apparent. But it was the texture and tonality in the lower-mid and bass that really impressed, with much greater definition and detail readily apparent. Dynamic speed, precision and substance were all improved along with the shape and duration of individual notes, making dynamic contrasts more emphatic and musically effective. This increase in presence extended across the entire range, brass in particular gaining body and a satisfyingly realistic rip to its tone. Overall timing was also improved with musical phrasing making more sense. [...] This ELAC super-tweter extends the performance available from existing speaker systems in a significant and musically imporlant way. High-frequency extension is no optional tweak - it's a musical necessity, making your system more natural and more naturally communicative." hi-fi+ review, no.42 (December 2005)

Sound wave dispersion pattern
(click to enlarge)
X-JET loudspeaker	4Pi two way loudspeaker
5120 Hz sound wave dispersion - tridimensional pattern comparison
8127 Hz sound wave dispersion - tridimensional pattern comparison
11945 Hz sound wave dispersion - tridimensional pattern comparison
16255 Hz sound wave dispersion - tridimensional pattern comparison

4PI used in:
	Spirit of Music CE
	FS 607 4PI CE, 609 CE, 4PI PLUS.2 (add-on supertweeter)

The HT KST 25 V is a  25 mm special tweeter with Aluminium-Magnesium-Manganese alloy dome with integrated phaser and wave guide. The dome and voice coil former are made of one piece. Sensitive glueing joints are thus avoided and distortions efficiently prevented. The driver is extremely heat-resistant.

The shielded powerful magnet system provides for high efficiency.

The X-JET is a unique combination of a flat (nomex honeycomb with crystal membrane) ring radiator midrange driver and a concentrically arranged JET III tweeter .

By this the X-JET design approaches the radiation pattern of an ideal point source! This facilitates an optimized acoustic power response and results in a homogeneous and very wide sound dispersion angle (s.a. the graphics below) which provides for a new kind of relaxed but very precise and detailed reproduction.

X-JET coaxial system versus conventional 2 way system tridimensional pattern comparison - 2756 Hz sound wave dispersion

The ultra lightweight honeycomb diaphragm provides a reduced stray magnetic field combined with a strong neodymium drive. The system is driven by a 78 mm moving coil. High efficiency is achieved using coppered aluminium flat wire, edgewise-wound, on a ventilated Kapton® bobbin.

X-JET of the second generation: further optimized magnet system, improved internal design with additional damping, new midrange membrane configuration with Nomex honeycomb material / phenol paper top layers and crystal membrane. This results in an extended transmission range of the midrange part of the X-JET which facilitates more linear crossovers to the woofers and tweeters of the FS 609 CE.

The new X-JET system yields a upper cut-off frequency of 50 kHz. This makes the loudspeaker an ideal component for the reproduction of DVD-A and SACD.

X-JET COAX Driver exploded view

• Coax white paper

X-JET used in:
	FS 210 Crystal Edition
	FS 509 VX-JET
	607 CE, FS 607 4PI CE, 609 CE

Two unique worlds of hi-end sound reproduction that can be found both in one loudspeaker:

- [X-JET and 4Pi] in the flag-ship FS 609 CE and in FS 607 4PI CE

or separated:

- [4Pi] in Spirit of Music CE

- [X-JET] in FS 607 CE and in FS 210 CE

X-JET COAX driver	4PI TWO way
5120 Hz sound wave dispersion - tridimensional pattern comparison

X-JET		X-JET & 4PI		4PI
FS 210 CE	FS 607 CE	FS 607 4PI CE	FS 609 CE	Spirit of Music CE

The stamping of the aluminium foil looks like the surface of a large crystal, this is where the term "Crystal Membrane" come from. This stamping stiffens the aluminium dome considerably which diminishes the membrane-internal resonances resulting in less sound coloration and additionally improves the large signal behaviour noticeably.

The voice coil is not only - like usually - joined to the neck of the paper cone, but also to the bottom of the aluminium dome. This design results in the expansion of the transmission range of the respective woofers or midrange drivers by nearly an octave. Therefore the abbreviation "XR" (eXtended Range) has been introduced.

Due to the specially wide double asymmetrical ('DAS') rubber surround, ELAC's TT 180 woofer can handle up to ±15mm long stroke. This provides maximum level supply and mellow low bass. For a driver this size, such a large displacement represent a unique engineering achievement.

Crystal AS-XR cone used in:
	FS 210 CE, Spirit of Music CE
	BS 243, BS 243 Limited Edition , BS 253, BS 244, FS 247, FS 247 Sapphire Edition, FS 248, FS 249
	BS 243 BE, BS 244 BE, FS 247 BE, FS 248 BE, FS 249 BE
	BS 253, FS 257
	305 CE, 310 CE, 310 Indies Black, 330 CE
	FS 509 VX-JET
	607 CE, 607 4PI CE, 609 CE

Most of ELAC Speakers use ELAC’s proprietary aluminium sandwich technique. All ELAC Aluminium Sandwich drivers are designed, engineered and manufactured in-house at our facility in Kiel, Northern Germany.

In a special gluing procedure, a 0.2mm thick aluminium foil layer is combined with a cellulose cone forming a sandwich membrane. Available in a number of sizes from 115mm to 250mm in diameter, both active and passive drivers are used in ELAC cinema packs, stereo speakers (both bookshelf and floorstanding), centre channels and subwoofers. This technique, in combination with ELAC’s special wide double asymmetrical ('DAS') rubber surround, retains the transient benefits of cellulose cones with the torsional rigidity of aluminium and allows exceptionally long cone throw for better handling of high signal levels and low bass.

AS cone used in:
	BS 62.2, BS 63.2, FS 67.2, FS 68.2
	BS 182 , BS 184, FS 187, FS 189
	BS 203 A, FS 207 A
	BS 133 JET, FS 137 JET
	SUB 111.2 ESP, SUB 211.2 ESP, SUB 211 D, MicroSUB 2010 BT, SUB 2040 D, SUB 2060 D, SUB 2080 D

The new LLD driver technology (Long Linear Drive) is based on the movement of a short-wound coil (winding height: 6.5 mm) in a long air gap (height: 16 mm) with a homogeneous magnetic field. This design results in extremely linear (without distortions) movement within an amplitude of ±8 mm. The voice coil exactly mirrors the applied audio signal.

The maximum displacement is an impressive ±16 mm.

ELAC's new woofers use high-quality titanium bobbins for greater mechanical stability. This also reduces eddy-current losses and helps achieve deeper and more precise bass reproduction.

Neodymium magnets are used to increase magnetic flux density and to save space, providing optimum magnetic field geometry and greater efficiency. Using several small magnetic plates reduces air noise and helps to keep the temperature low even under high load.

LLD used in:
	330 CE
	FS 509 VX-JET
	607 CE, 607 4PI CE, 609 CE
	SUB 2060 D

ESP® is a frequency- and power-dependent control system. Like in a car, where the Electronic Stabilization Programme permanently controls the balance and ensures a reliable performance of the car even in extreme situations, ELAC's ESP® subwoofers act in a similar way. Their electronic components ensure that even under maximum power no background noises can be detected. Contrary to conventional active subwoofers, it is now practically impossible to overdrive ELAC ESP® subwoofers.

The measuring diagrams show the harmonic distortions (excitation frequency, K2, K3) and the disharmonic (non-linear) distortions. The Y axis defines the volume (dB), the X axis the frequency (Hz). Clearly, the 'more loudly' a subwoofer plays, the more disharmonic distortions it produces.

Subwoofer without ESP® : The above subwoofer produces distinctly more non-linear distortions.

Subwoofer with ESP® : The measurement shows noticeably less non-linear distortions. Fewer peaks mean almost no distortions.

ESP used in:
	SUB 50 ESP, SUB 111.2 ESP, SUB 211.2 ESP, SUB 211 D, SUB 2040 D, SUB 2060 D, SUB 2080 D

This special cabinet consists of a combination of extruded aluminium design, aluminium casting and MDF with horizontal and vertical internal tension rods. This patented design concept offers optimized sound and avoids resonances.

Cross-frame hybrid technology is used in:
	607 CE, 607 4PI CE, 609 CE