Non circular sound propagation devices

[nysbob]

What does this do for you? 3 speakers in each cab. View attachment 329065

3 round speakers.

 

[Jazz Ad]

If you can live with round speakers and just want a different box shape, Epifani make these deliciously 70s styled bass cabinets.
[Invalid or Expired Link Removed]
It's like they escaped from a Clockwork Orange.

 

[Jeff Scott]

Back in the '70s other configurations were available, of the planar......

I still listen to my Magneplanars going on almost 25 years, now, wonderful speakers .....for my stereo system. I use round drivers in square (rectangular, actually) boxes for my electric bass and guitar needs.

 

[T-Bird]

Hi.

That's in interesting notion, Sam. I've never heard that before, and frankly, don't understand what a "logarithmic cone" is.

Do you have reference?

Wrong word, exponential was the one I was after .
I did catch that when I re-read my reply, but lazied out and thought no-one would notice .

A straight cone is easier to manufacture, so it's a close enough for MI use even though an exponential cone would be stiffer. Obviously.
Most of the Hi-Fi cones I've encountered and larger PA cones are more or less exponential in shape.

Small, in his definitive works, never even refers to a "cone." He talks about a "piston." His formulas are all based on the assumption that the loudspeaker has a "piston," in other words, is infinitely stiff. The actual shape of the cone, I would suggest has much more impact at higher frequencies.

AFAIK he didn't adress the impedance matching since there was very little to do to improve that at the time. The impedance matching is IMO also somewhat unrelated to his (/their, Thiele should be mentioned as well) studies.

It's easily experimented by attaching either a dome or a flat disk the size of the outer diameter of the cone onto the cone (or changing the diameter of the dust cap for that matter). The results are interesting to say the least.
But not in a good way, that's the reason we don't see many flat "cones" except in the high frequency transducers (and in Car "Hi-Fi" subs ).

Regards
Sam

 

[Minussss3db]

Some older alnico full range 6x9's from the sixties are simply excellent,

as well as a pair of MA carbon fiber 6x9, I removed from my car, and have in my house....these also simply sound excellent.

There have been a few guitar amps with 6x9's also...

and the Heil 's Big Transducer with a FaitalPro 12", basically rules the world...

ok

Good night,
-3db

 

[Doublesixes]

For you sound buffs who might be interested in some different shapes and concepts over the years, I posted an interesting article from"Audio" magazine on just that topic.

I expect the OP will get a kick out of the Ohm vertical driver, which I believe is still in production. Personally, I'm very fond of the "Hypersonic" driver. What a cool idea!

http://acmebass.com/archive_files/mag_articles/audio_magazine/Speaker_Revolution_11-1997.pdf

For those interested in speakers and audio in general the "Archives" section of our Acme website has a wealth of historical stuff, and as time goes by, I hope to add more. I saw one poster refer to Hofman's Iron Law (one "f" not two...), the definitive article about which was done by Henry Kloss. That article is in my files, and I hope to get it posted before too long.

Anyway, here's a link to the Archives: http://www.acmebass.com/andysworld/oldmagazines.html

The sire is being worked on. I hope the links work at this time!

Thanks,
Andy

Andy, after reviewing the pfd you provided, I believe the NXT panel seems like the closest speaker design that most resembles what I vaguely remember. Wouldn't it be marvelous if such a design could be used in bass amplification? Thanks all for the great information. I love this site

 

[acmebass]

Hi.



Wrong word, exponential was the one I was after .
I did catch that when I re-read my reply, but lazied out and thought no-one would notice .

A straight cone is easier to manufacture, so it's a close enough for MI use even though an exponential cone would be stiffer. Obviously.
Most of the Hi-Fi cones I've encountered and larger PA cones are more or less exponential in shape.



AFAIK he didn't adress the impedance matching since there was very little to do to improve that at the time. The impedance matching is IMO also somewhat unrelated to his (/their, Thiele should be mentioned as well) studies.

It's easily experimented by attaching either a dome or a flat disk the size of the outer diameter of the cone onto the cone (or changing the diameter of the dust cap for that matter). The results are interesting to say the least.
But not in a good way, that's the reason we don't see many flat "cones" except in the high frequency transducers (and in Car "Hi-Fi" subs ).

Regards
Sam

It seems to me that when you use the words "logarithmic and "exponential," you must be looking at the cone from the side, and referring to the apparent "flare rate," as if it were a horn. Many speaker cones have a "curved" profile when viewed in this fashion.

In fact, the proper term is "curvilinear," and in fact, is less stiff than a "straight" cone. The reason people use cones shaped like this it that at higher frequencies, the center of the cone decouples somewhat from the outer circumference of the cone, resulting in an effective reduction in the diameter of the radiator.

This results in a more extended top end, at the expense of lower distortion at low frequencies, where the stiffer "straight" cone more closely approximates the piston ideal. As with everything in loudspeaker design, there are trade-offs, and this trade gives the designer more top end, and greater low-end distortion, because the decoupling occurs at lower frequencies, too.

Most hi-fi speakers use "straight" cones, not curvilinear ones, because "straight" cones have lower distortion at low frequencies. Most MI speakers use curvilinear cones.

But not mine. My MI speakers are also hi-fi speakers.

I don't know what AFAIK means, but the work of Thiele is subsequent to, and derivative of, that of Small. I don't work with discrete "alignments" as Thiele did, but approach designs as on a continuum. For that reason, I'm pretty much a Small guy.

I don't understand the purpose of your test, and you haven't actually explained the results, so I can't comment. I can assure you that attaching additional masses to drivers will have effects unrelated to this discussion, however, and that a "flat" cone would be very difficult to make stiff, which is the ideal for bass reproduction. Someone, Sony I think, actually used a honeycomb matrix a few years back, in order to make a flat cone stiff and rigid. That idea never really caught on. But a "straight" cone is very good, and cheap to make, as you say, which sort of brings us full circle. That's why they're so hard to beat!

Cheers,
Andy

 

[acmebass]

Andy, after reviewing the pfd you provided, I believe the NXT panel seems like the closest speaker design that most resembles what I vaguely remember. Wouldn't it be marvelous if such a design could be used in bass amplification? Thanks all for the great information. I love this site

Yeah, it's pretty groovy, alright. Very directional, though.

I'm glad you like my archives.

Andy

 

[acmebass]

Most of the Hi-Fi cones I've encountered and larger PA cones are more or less exponential in shape.

I just remembered something relevant.

Among my favorite speakers in the world are the classic Tannoy dual-concentrics, in which the woofer cone DOES have an exponential flare rate, because it is used as the mouth of the horn tweeter, which has it's own voice coil, magnet, and phase plug mounted behind the woofer's motor.

This is the exception to the rule, and if you examine some 12" Tannoy Gold dual drivers, from the classic Devon system, for example you will find that they actually add strut braces to the cone in back, because the curved shape of the cone adds distortion at low frequencies, and must be stiffened up in order to maintain both the horn-flare AND low-distortion bass.

Damn- those things sound great!

Andy

 

[David Jayne]

I'm waiting for field-coils to make a comeback once neo becomes too environmentally damaging and expensive. Heck, it should be possible to make field coils even lighter than neos, with common materials. Just gotta deal with the high voltage. Or current?
Very common in large electric motors, why not speakers?

 

[mystic38]

Pretty obvious you have never sat down and listened to a pair of Quad Electrostatics?..

Open airy, honest, 3D image, significantly better transient performance, lower coloration and in a completely different class to conventional speakers. For classical music in particular they could not be beaten.

but... OTOH expensive, large, restricted bass response and if you cranked them then you got blue flashes as they arc'd.. and given they would be the size of a 62" HDTV for a decent bass response you can see why they didnt stick around!

When you say "distinctive quality and tone" What you are implying is distortion. Those oddball speakers really didn't perform that well. .

 

[maestrovert]

in the late '70s-early '80s i had a friend who fancied himself an audiophile; he had a set of the large(r) Magnaplanars that sounded ok for upper mid and high frequency material , BUT they were sadly lacking in the area of bass frequencies, a fact brought home especially after he bought a pair of Beveridge S2W1s...he dumped the Magnaplanars pretty cheap soon after.

i can't imagine a planar design being workable for bass instrument amplification purposes.

 

[Jeff Scott]

Pretty obvious you have never sat down and listened to a pair of Quad Electrostatics?..

I prefer Martin-Logan electrostatics!

 

[Jeff Scott]

in the late '70s-early '80s i had a friend who fancied himself an audiophile; he had a set of the large(r) Magnaplanars that sounded ok for upper mid and high frequency material , BUT they were sadly lacking in the area of bass frequencies, a fact brought home especially after he bought a pair of Beveridge S2W1s...he dumped the Magnaplanars pretty cheap soon after.

i can't imagine a planar design being workable for bass instrument amplification purposes.

When I lived in apartments, having reduced bottom end along with the bi-polar radiation of the speakers were actually an advantage. Once I moved to a single house, I bought a Definitive Technologies Super Cube II to bring everything into balance down to 14 Hz.

 

[Munjibunga]

If non-conventional, non-conical pressure transducers (speakers) sounded significantly better than, or were more efficient and/or more economical than standard transducers there'd be plenty of them out there. But they're not, so there aren't.