I recently seen a Jamo R909 at glorietta 4. near the theaters... and it proudly stands besides plasma TV's on display. just wondering how it performs. read it at
www.jamo.com that it was their reference series for floorstanders. also how much kaya ito?...
here's what it looks like:...
R 909
Dipolar loudspeakers have existed for many years, but most examples have been electrostatic-types. While the sonic quality of these designs is often very good the main problem with this type of speaker is bass frequency reproduction is often compromised - they aren´t able to produce the characteristic physical bass ‘thwack´ in your midriff. To solve this problem, chief acoustic engineer Henrik Mortensen decided to use electrodynamic loudspeakers instead of electrostatic ones… the results were amazing.
“During the process we faced quite a few challenges”, Henrik Mortensen admits. “It was quite a task, to make an elegant and aesthetic design for a loudspeaker of this size. But I think we´ve succeeded with the Jamo Reference R 909… without compromising performance at all”!
With the launch of the Jamo Reference R 909 we offer you the opportunity to experience music, as it should be heard - live! This revolutionary new floor-standing dipolar loudspeaker employs two massive 15in woofers, a Seas magnesium midrange driver and a customized Scan Speak Revelator tweeter, all mounted in a 43mm thick baffle made of a unique multi-ply construction... this is a speaker that is set to change the face of the high-end speaker market.
The R 909 is the perfect match for the highest quality amplifiers on the market. However, with a high sensitivity of 89dB and offering a very stable load at 4ohms it doesn´t need a power plant to drive it… although it will handle more than 800 Watts of peak power if you really want to go there! The design and drivers used reproduce wonderfully transparent vocals and a response so dynamic that it´s hard to believe that you´re actually listening to a speaker. The exceptionally firm bass, blessed with immense transient speed, precision and fluidity throughout the frequency range (and absolutely no colouration or reverberation) simply puts you in the middle of the sound experience.
It may all be hard to believe it´s possible but a quick demonstration is all it takes to be convinced - sit down, take a listen to the R 909 and you´ll hear the proof.
Specifications:
system 3-way dipole
Woofer (inch/mm) 2 x 15 / 2 x 380
Midrange (inch/mm) 5½ / 150
Tweeter (inch/mm) 1 / 25
Sensitivity (dB - 2,8V / 1m) 89
Impedance (Ohm) 4
Weight (kg/lb) 63,1 / 139.1
Dimensions (HxWxD/mm/in) 1276 x 488 x 541 / 50.2 x 19.2 x 21.3
Frequency Range 25 - 30.000
Crossover Frequency 250 and 2.000
powerShortTerm Min 800
Dipolar
Placing a cabinet speaker (pressure transducer) in a room creates its own unique challenges. So exactly how does a dipolar speaker (or velocity transducer) ”behave”?
Due the dipolar radiation pattern, sound is distributed from the front and rear of the speaker – in opposite phase. This is important because with a conventional loudspeaker, side wall (i.e. 1st order) reflections typically are in opposite phase with the direct transmitted sound from the drive units i.e. they sound annoying.
However, with a dipolar radiation pattern there is virtually no "sideways" sound transmission and so the critical 1st order sound reflections are practically eliminated.
But, you might ask, what about the sound transmitted from the rear of the speaker… doesn´t that destroy imaging and the soundstage?
Actually, when placed correctly the laws of psycho acoustics come into play. The human ear uses the first sound received (the 1st wave-front) to determine the direction of the sound (i.e. where it´s coming from). That means that even if reflected sound is slightly delayed it doesn´t affect the brain´s ability to determine direction.
If a dipolar speaker is placed a minimum of 3ft/1 m away from the rear wall and angled in slightly (as a serious listener with cabinet speakers would probably do anyway), the reflected sound will be delayed (due to physical distance and the fact it will be bouncing off two boundaries before reaching the listener´s ears) but it still gives directional cues. Now the 2nd order reflections add ambience and give the listener the impression of a much larger room.
Front baffle
The 1.7in/43mm thick front baffle is made from no less than seven layers of MDF board, glued together and shaped under high pressure. The rounded shape provides optimum working conditions for the drivers as it prevents diffraction and improves rigidity even further.
The baffle itself is attached to a 60lb/26kg cast-iron base housing the cross-over network and the bi-wiring XL binding posts, they connect directly to the crossover network placed inside the base, so securing the best possible signal path. A solid double 5x60mm stainless steel brace with a special damper ensures a rock solid connection between the baffle and the base.
Midrange
In order to fulfill the R 909 brief we also had to use state-of-the-art technology for the midrange driver. Employing a patented Neodymium magnet arrangement, the Seas unit uses a magnesium cone for its stiffness and low weight, both vital qualities for dynamic response. Thanks to the HCC (Hard Conical Cone) technology the driver is able to reach all the way to 9kHz before any significant cone break-ups occur. This makes for extremely low distortion throughout the range plus a very open and detailed midrange for optimum voice reproduction. Turned from solid brass the centre-plug has a cooling effect on the voice-coil, providing greater power-handling capability and most importantly, extra sonic stability when playing at high volume levels.
Tweeter
There was only one choice when it came to choosing a tweeter to reproduce the delicate treble frequencies… the legendary Revelator from Scan Speak. However, since this model features a relatively large face-plate, it would have needed to have been placed further away from the midrange than would be ideal. So, in order to obtain a seamless transition with the midrange driver, we chose to fit a smaller cast-alloy face plate.
The tweeter features a 1in textile dome which is coated several times to obtain a unique combination of dynamic linearity and resonance damping, the result being an incredibly smooth, linear, dynamic and incredibly transparent sound.
The driver´s Symmetric Drive Technology - a copper ring on the pole that extends past the voice coil, curving into the dome chamber - practically eliminates electrical phase shift. And, just as it does with the midrange, it also lowers distortion significantly.
To eliminate turbulence the double-damped, optimized chamber behind the magnet system is also equipped with an anti-resonator-plug. And the specially designed chamber under the cloth surround minimizes air noise and compression. Actually this tweeter is so carefully manufactured that damping unwanted resonances using ferro-fluid - the usual way - is rendered unnecessary!
Woofers
Most woofers are developed to work in a cabinet, and as a woofer constructed for a dipole application is very different from a traditional boxed one we had to develop a special woofer for this open-baffle application.
These huge bass drivers employ high quality magnesium baskets plus lightweight, air-dried paper cones with a rubber suspension. The time-consuming process of letting the cones air-dry – instead of just pressing out the water in the former - has resulted in a thicker, and thus more rigid, material for the same low weight. Although paper cones might be out of fashion in some circles they have the ability to start/stop moving incredibly quickly, can reach very, very deep and they endow the drive unit with great sonic precision and musicality.
X-over
As should be apparent from the drive unit descriptions, we wanted to start out with drivers of immense fundamental quality, precisely so that we would only need minimal assistance from the cross-over!
Consequently, the cross-over in the Jamo R 909 is of a relatively simple – in the most positive sense of the word – low-order configuration. The advantages of using the 2nd order filters that are in the R 909 is that both electrical and phase angles are kept at very small values, something that´s of great importance both in terms of sound quality and the eventual load on the amplifier. The use of quality Solen foil-capacitors and air-coils in the crossover further ensures sound quality.
