A square 3-way single cone, how can this work?

[Lekha]

Image from this post.

I am still contemplating how this square cone works with just one voice coil powering it. Certainly, the additional tweeter horn in the middle (4) could be powered by a separate voice coil. This square cone has much more surface area than a "normal" round cone of the same diameter, measured from one corner of the square to the other. It features a square surround suspension and most likely has two spiders to help centre that massive cone.

The larger area closer to the surround (1) is intended to emit low frequencies (LF), while the area (2) emits mids, and the smallest area (3) emits high frequencies (HF). Therefore, the horn in the middle might function as a super tweeter. From what I understand from its designer engineer, he is not inclined to write a patent or disclose what’s inside that box. Can anyone guess how this might work?

 

[SIY]

I am still contemplating how this square cone works with just one voice coil powering it.

Mechanical crossover- the mass of the cone outside the elastomeric surround causes the entire cone to move at low frequencies but decouple at higher frequencies.

 

[Lekha]

Mechanical crossover- the mass of the cone outside the elastomeric surround causes the entire cone to move at low frequencies but decouple at higher frequencies.

It could be, but there are three regions that are decoupled from each other, and in one piston movement, they could move in different unpredictable ways. Additionally, it is not a cone in the traditional sense, as we think of a circular one; rather, it consists of four equal pieces glued together in the #1 area, and it appears to be made from one piece in the #2 area, while the #3 section is a circular one-piece section. It would be quite challenging for the tiny #3 section to push the other sections forward (or back) without going out of alignment, leading to a sort of cone breakup. And if he had added stiffeners at the back, the whole concept of a 3-way speaker would likely be compromised, I suppose.

 

[Old_School_Brad]

Mechanical crossover- the mass of the cone outside the elastomeric surround causes the entire cone to move at low frequencies but decouple at higher frequencies.

The video source appears to show an electrical crossover in use.

 

[Lekha]

The video source appears to show an electrical crossover in use.

View attachment 427289

It has a fourth element in the middle within the coil former area, which is some sort of horn tweeter, and there's also a separate super tweeter on top of that box.

 

[sq225917]

We shouldn't be asking how it'll work. The better question is why, what's the benefit? It'll just trade some of the benefits of a point source for a bunch of modulation distortion, frequency aberrations and other nonelinearities.

 

[SIY]

It could be, but there are three regions that are decoupled from each other, and in one piston movement, they could move in different unpredictable ways.

Yes, the elastomer is different (whether material, dimensions, or both) for each of those couplings.

And yes, it's an idiosyncratic way to do a crossover, which is the sales point. Not something *I* would do in a speaker design, but I'm not in that marketplace.

 

[DVDdoug]

It's hard to believe that it will perform better than a traditional speaker of the same cost.

The concept of a "mechanical crossover" reminds me of whizzer cones. It's been awhile since I've heard a speaker with a whizzer cone. I don't know if they do anything and they are adding mass which could be bad for high frequencies. They never worked as well as a true coaxial but it costs almost nothing to add the whizzer.

 

[voodooless]

I very much doubt it’s just one voice coil. Why have so many wires and crossover components? The thing in the middle looks like an assembly of a dome tweeter, they come with a voice coil attached. Did they just glue a tweeter on the dust cap of the “midrange”? No picture from the rear seems suspect as well.

 

[mhardy6647]

Altec Biflex and the very old Pioneer (Fukuin) dual-compliance drivers did this trick long, long ago. Round, though. It works... OK.

source: https://lansingheritage.org/html/altec/catalogs/1954-home.htm



Rockin' a pair of the 8" Pioneers at my house, as it happens.


Actually, there's a gorgeous pair of 15" Altec Biflex drivers here, too... but tucked away for a rainy day, not in enclosures.

 

[Lekha]

Altec Biflex and the very old Pioneer (Fukuin) dual-compliance drivers

They are 2-way, while the above is a 3-way design with an additional horn tweeter in the middle, and the entire sound diffuser is not circular, but square. I first saw the round one on YouTube, then went searching and found the square cone one.

 

[mhardy6647]

They are 2-way, while the above is a 3-way design with an additional horn tweeter in the middle, and the entire sound diffuser is not circular, but square. I first saw the round one on YouTube, then went searching and found the square cone one.

Yes, so I saw.
Square drivers were a thing for a minute in the (?) 1980s (maybe late 1970s), thanks to Sony's accurate pistonic movement (APM) drivers.
Crossing them with coaxes (of any sort) is... odd.

 

[Penelinfi]

It's hard to believe that it will perform better than a traditional speaker of the same cost.

The concept of a "mechanical crossover" reminds me of whizzer cones. It's been awhile since I've heard a speaker with a whizzer cone. I don't know if they do anything and they are adding mass which could be bad for high frequencies. They never worked as well as a true coaxial but it costs almost nothing to add the whizzer.

Whizzers direct high frequencies afaik. I've chopped them off before and it does change the sound

 

[mhardy6647]

Whizzers direct high frequencies afaik. I've chopped them off before and it does change the sound

The do also enhance the output (SPL) at higher frequencies, all else being equal. Yes, the bandwidth will change, perhaps dramatically, upon a whizzerectomy.

 

[mhardy6647]

Whizzerectomy -- sounds like something for which a urologist is needed... probably some pre-procedure counseling, as well.


Ahem. Here's a truly bizarre real-world example (of a whizzerectomy, that is). Generally, when we think of twincone "fullrange" drivers (at least the kind using a whizzer, as opposed to dual-compliance surround drivers as mentioned in post #10 above), we expect relatively small (≤ 8 inch/200 mm driven cone) drivers -- but it wasn't ever thus. In the glory days of hifi (1950s-60s) 12 and even 15 inch "fullrange" drivers were far from uncommon. This was driven mostly by economics, but, obviously, the "fullrange" approach was stretched very thin by such products. While some large "fullrange" drivers (especially cheaper ones) used "normal" sized (small) whizzers, some didn't.
Case in point (I'm going somewhere with this!), the range of 15 inch "fullrange" drivers from Electrovoice: the "entry level" (cheap) "Wolverine" LS-15, the midline SP-15B, and the premium SP-15. These drivers had 2 inch edgewound voicecoils and truly mammoth whizzers. EV claimed HF response to 13 kHz, but that was probably rather optimistic.
Here's a pair of unbaffled LS-15s to give some sense of what we're talkin' about.


The whizzer is on the order of 4 inches (100 mm) in outer diameter.

Now, here's where this is going.
As it turns out, no less than RCA, for reasons lost in the dim mists of time (at least to me), sold an OEM version of the LS-15 (RCA SPR-15). Oddly enough, a pair of these wandered into my life some years back. But here's the really odd part - at some point, somebody de-whizzered them. I have no idea why... the very sensitive LS-15's rather limited power handling capacity and accordion surround would make it a rather lackluster (if not downright lousy) woofer! Nevertheless, this pair, at least, is so "configured".

 

[Lekha]

Do you see any wizzer in the square cone speaker? Do you notice how the #2 part change from round to a square cone, but with the ends cut so that it gets 8 edges?