He published his theories in "Loudspeakers - Ted Jordan" Focal Press 1962. Also several Wireless World articles about that time. They are certainly worth reading, especially for his view of the necessity of cone 'breakup'. But his maths, especially for bass design was seriously wonky. His ideas on stereo sorta live on in modern "sound bars".
I investigated many of his ideas, working for a large speaker maker in da previous Millenium including SCanned Laser Plots & FEA/BEA. You don't need a hyperbolic flare to get the cone 'breakup' behaviour he and I like.
The designs I've listened & measured, including the Jordan Watts module and the Audio & Design Titanium Cone Loudspeaker weren't impressive. Even worse was his 50mm module which, IIRC, used a straight sided aluminium cone.
I haven't heard his Eikona unit (the last he did before he passed on) in present Jordan products which, I think, reverts to a 4" hyperbolic Aluminium cone.
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Having had a look at the patent, it mostly mentions "discontinuities" and "patterns". Since we are talking about wave propagation it is implied that the discontinuity has to be relevant to the propagation mechanism, creating scattering centres. For the waves on a loudspeaker cone, embossing or placing a dot of paint might be sufficient. Drawing on the cone with a felt tip pen probably is not. For some effect to take place in an enclosure wall, I would think something else is needed, e.g. a cavity (not such a good idea in a loudspeaker enclosure) or an embedded higher density material of the right shape. As a homework one could of course run the full FEM simulations to see what happens, how much mass is needed, and what is the magic behind the pattern.
From the patent is is obvious that higher density material is not important, but only the specific pattern of painted dots! 🙄
Wombling by this day after an enjoyable stint in cardiology, so my sole post here. Speaking as somebody with zero horse in this non-race / competition, a couple of observations that come to mind:
On the subject of patents [and again speaking generally] it's worth keeping in mind that they're not obliged to 'work' as descibed, or proposed [thank goodness, since I can point to examples for faster-than-light communications through unknown dimensions]. They just have to be original. Many aren't even that -they just got through because the examiner didn't do their job properly, have any knowledge of the field, or both.
A good example: https://patentimages.storage.googleapis.com/ef/3b/8b/91cfa120a70f05/US9247339.pdf -the reasoning being, per claim 1,
Earlier in the document, it even references the mass of an open E double bass string. Of course, last I checked, pressing the string at a certain point along its length to the fret not only reduces its effective resonating length, but also its effective resonating mass, which instantly explodes any & all such cobblers about matching Mms [irrelevant too since the air load varies with local climatic conditions] to the ephemeral vibrating mass of some unspecified instrument.
As for wideband drive units, they're not all created the same way, so there are variations in terms of progressive [or otherwise] decoupling of parts of the main cone and / or transitions to additional sub-surfaces e.g. direct-bonded central caps, additional bonded sub-cones etc., so the actual functional / resonating mass of the moving components at a given frequency is unlikely [especially above the notional piston corner and certainly the VC point-source corners] to be equal to the total Mmd relevant to LF measurements at / around Fs / F0. This goes right back to Altec's decoupled biflex designs & earlier [later for that matter] less specifically decoupled types also. So ignoring EnABL itself [since different approaches exist, it's difficult to pigeon-hole it anyway] & simply speaking in general, localised changes to the mass / damping / rigidity of the substrate are likely to have some effect, especially if the starting substrate mass at & around that point is already small. It won't necessarily be large -in most cases it won't be, but the laws of physics mean that there will be something.
Speaking generally, that doesn't mean anybody is obliged to blindly accept everything that is written in a patent in total [or part]. Dave is an example of one who simply took elements of this particular idea and adapted from there.
On the subject of patents [and again speaking generally] it's worth keeping in mind that they're not obliged to 'work' as descibed, or proposed [thank goodness, since I can point to examples for faster-than-light communications through unknown dimensions]. They just have to be original. Many aren't even that -they just got through because the examiner didn't do their job properly, have any knowledge of the field, or both.
A good example: https://patentimages.storage.googleapis.com/ef/3b/8b/91cfa120a70f05/US9247339.pdf -the reasoning being, per claim 1,
Earlier in the document, it even references the mass of an open E double bass string. Of course, last I checked, pressing the string at a certain point along its length to the fret not only reduces its effective resonating length, but also its effective resonating mass, which instantly explodes any & all such cobblers about matching Mms [irrelevant too since the air load varies with local climatic conditions] to the ephemeral vibrating mass of some unspecified instrument.
As for wideband drive units, they're not all created the same way, so there are variations in terms of progressive [or otherwise] decoupling of parts of the main cone and / or transitions to additional sub-surfaces e.g. direct-bonded central caps, additional bonded sub-cones etc., so the actual functional / resonating mass of the moving components at a given frequency is unlikely [especially above the notional piston corner and certainly the VC point-source corners] to be equal to the total Mmd relevant to LF measurements at / around Fs / F0. This goes right back to Altec's decoupled biflex designs & earlier [later for that matter] less specifically decoupled types also. So ignoring EnABL itself [since different approaches exist, it's difficult to pigeon-hole it anyway] & simply speaking in general, localised changes to the mass / damping / rigidity of the substrate are likely to have some effect, especially if the starting substrate mass at & around that point is already small. It won't necessarily be large -in most cases it won't be, but the laws of physics mean that there will be something.
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as someone who has been to those rodeos too - some much less pleasant than others -- I hope that your cardiac ride was successful in any event. if not actually enjoyable. remaining vertical is good. mostly. ;-)
best wishes, eh.
best wishes, eh.
I have given that some thot … easier to CNC a pit than preserve a bump thru finishing.
dave
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Dave, what are your thoughts about EnABL'ing a subwoofer? Any possible benefit?
The reason I ask is, I'm going to purchase a Caldera 10 sub (when they come back in stock) and the designer, Viet aka XKA, already heavily doped the paper driver. When dealing with such low frequencies, can the process help?
The reason I ask is, I'm going to purchase a Caldera 10 sub (when they come back in stock) and the designer, Viet aka XKA, already heavily doped the paper driver. When dealing with such low frequencies, can the process help?
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Yeah, that's what I was thinking. Budget subwoofers are notoriously 1 note. I was wondering if EnABL be able to improve them to 1.25 notes. 🙂