Very interesting speaker design (the "hidden woofers" trick)

This Genelec 8351 is quite interesting, at least from my point of view as a loudspeaker engineer. There is a tweeter in the center, concentric with a midrange cone that appears to be surround-less. At least, no conventional surround, the edge seems terminated to the surface. The surface is all a giant waveguide for directivity. And the woofers are actually inside, with the bass energy propagating out through the controlled slots top and bottom (those aren't ports, though there IS a port on the back). The whole deal can network together with others to make a system that can calibrate itself and adjust to the listening environment.

By the way, you heard it here first: the future revolution in home sound will be micro-arrays, controlled by DSP to give (*fairly*) even response throughout the room…tell you more in another thread.

 

I like this design approach, controlled dispersion, and high directivity in the midrange. I will be asking my local music store who stock Adam, Dynaudio, etc if they would consider ordering these. I'd like to hear them.

 

The return of the whizzer cone?

 

It appears to be dual concentric! I have always liked the whizzer cone, and think it should be considered by driver manufacturers as a valid full range design option.

 

QUOTE="head_unit, post: 11277985, member: 5723"]
By the way, you heard it here first: the future revolution in home sound will be micro-arrays, controlled by DSP to give (*fairly*) even response throughout the room…tell you more in another thread.[/QUOTE]

Indeed. Systems based on wavefront and wave field synthesis are real and coming to commercial environments and to the home, has been evangelized for decades and systems do exist.... google on ie those terms and Fraunhofer, info on work and presentations including some fascinating microarray-based systems. Much of the original concept as applied to "the audio world' originated at TU Delft in the late-1980s; NHK and Fraunhofer were also main players in research and development dating back several decades. Several other major research groups now (pardon the pun) "active" in the field (which leads me to ask head-unit, are you at USC?)

 

See also Tannoy dual concentric and even a couple of Pioneers too. Both give excellent sound. Tannoy has both active and passive variants out there.

 

Let me put on my loudspeaker engineer hat, and tell you that whizzer cones can achieve fairly flat on-axis response, but they have less off-axis response than a "real" tweeter. Good results are also fiendishly hard to achieve, and often expensive.

This Genelec has an actual tweeter, and the woofer cone seems basically glued at the outer edge.

emmodad, I don't teach at USC, though I do know some of the USC & Audyssey folks. Audyssey technology is cool; it would be interesting if they developed it into something arrayable.

 

Just having a closer look at the photo, I think you're correct. The Genelec 8351 does not appear to be a dual concentric. I suppose I should just go to their website for a closer look, and specs. True also, the whizzer design is highly directional. I prefer that, personally for near field listening. I have observed by speaker building experience, high directivity over the full range reproduces cleaner transients by virtue minimal boundary reflection and minimized time delay, and a sharply defined image. Speaker arrays are most effective as each section must be directional to project full range sound to the back rows, without major reflections nor phase interference from the adjacent sections. The entire array (s) functions as an axial and power response system that covers the entire audience with minimal fidelity loss.

 

The 8351 is a three way tri-amped coaxial design with acoustically concealed woofers. The tweeter and midrange are separate drivers in the classic dual concentric construction. (such as Tannoy, KEF, etc)

From the Genelec site:
The unconventional and delightfully compact 8351A Acoustically Coaxial Smart Active Monitor (SAM™) is a revolutionary achievement in three-way monitor design.The 8351A combines our breakthrough Acoustically Concealed Woofers (ACW™) technology together with our Minimum Diffraction Coaxial (MDC™) driver and Maximised Directivity Control Waveguide (MaxDCW™) to produce controlled directivity over a very wide bandwidth. Genelec Loudspeaker Manager (GLM™ 2.0) computer control allows for repeatable, consistent performance over flexible proprietary network. Genelec AutoCal™ measures and automatically align every monitor on the network for level, timing, and equalisation of room response anomalies.

Providing identical performance in both vertical and horizontal orientation, the 8351A delivers outstanding monitoring accuracy for music studios, post-production houses, edit suites, radio, TV and outside broadcast applications.
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I'd like to underline "controlled directivity over a very wide bandwidth". I am more curious than ever to audition the Genelec 8351.​