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Annular Tweeter what do they do different than domes

iridium

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#2
here is the patent #
Super tweeter
US 20050238197

Now I am going to read it.

iridium.
 

iridium

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#3
Now I see:
The voice coil appears to be connected in a unique manner; not in the center but a ring that runs approximately in the center of the radius of the cone.
You would need to look at the patent drawings.

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iridium

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#4
The diaphragm is less distorted at high frequencies; that is what the patent states.

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iridium

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#5
Never mind, different annular tweeter; JBL is using a compression driver tweeter.
I will study that one.
 

iridium

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#6
JBL M2 tweeter is the d2. It has 2 diaphragms in ring shape [think the silhouette of a tiny bicycle tire / annular means ring] instead of a dome.
Again, supposedly less distortion, and in the case 2 ring diaphragms with 2 voice coils for more power handling.

iridium.
 

AJ Soundfield

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#7
I see the JBL M2's have an annular tweeter, as in it is a ring. How do these work exactly and what do they do different than domes?
Dome

Ring radiator:



Instead of the voice coil driving the circumference of the dome, it drives the center "ring". So the driven surface radiates more like a donut than a dome. Less flex "distortion" at the center. But also narrower dispersion in the off axis.
No free lunch, both have their merits.
JBL borrowed the tech from BMS, even though they use to make their own ring radiators. The BMS version is SOTA. They take it further by doing a coaxial version, which is what I think is used in the M1 and 4367.
 

iridium

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#8
AJ Soundfield,
I made the wrong choice initially when replying.
Later realizing the JBL M2 speaker was using the D2 >>>compression driver<<<, and posting a Correction.
??? Is your second photo a correct analogy for the original question ???; besides the fact that it still is an annular driver.

Best to you,
iridium.
 

AJ Soundfield

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#9
Yes, the principle of ring vs dome remains. The D2 is a dual concentric aka coaxial arrangement of rings, the smaller ring produces the upper treble, the larger ring the lower. So you have a point source compression driver that goes low and still has good very HF dispersion. Large domes that can go that low typically have poorer upper HF dispersion.
 

RayDunzl

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#10
JBL:

 

iridium

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#11
Yes, the principle of ring vs dome remains. The D2 is a dual concentric aka coaxial arrangement of rings, the smaller ring produces the upper treble, the larger ring the lower. So you have a point source compression driver that goes low and still has good very HF dispersion. Large domes that can go that low typically have poorer upper HF dispersion.
AJ, does the D2 truly work as well as JBL presents?

A sad thing nowadays is that so many companies [not just audio] make things more complicated so that consumers [lemurs with cliffs] believe they have to have it!

iridium.
 

AJ Soundfield

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#12
AJ, does the D2 truly work as well as JBL presents?
Dunno, what exactly are they presenting?
As noted earlier, it will go low and have wide dispersion at VHF. Wider than a same diameter single dome compression driver that can go as low (apparently 800hz?)
 

RayDunzl

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Don Hills

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#15
Thanks, Ray. I think I misunderstood AJ's description, I somehow had in mind dual concentric diaphragms with concentric voice coils.
I don't see how the D2 would work as AJ described, both diaphragms appear to be the same size and cover the same range.
 

March Audio

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