Coaxials: Effect of Cone Depth and Xmax on HF Unit

[lucadelcarlo]

I'm seeking to better understand the interplay in a coaxial design between the HF unit and the surrounding woofer cone, in particular with regard to the cone's profile (depth, angle,and size) and its xmax, which I believe works a bit like a rapidly shifting wave guide on the other driver.

How, for example, would a small 3.5 in coax with a deep, sharply angled cone and 5mm of travel compare with one which is entirely flat and has a short xmax of 1mm, in terms of its interaction with the tweeter?

There are few if any small flat cone coaxes available, but this is precisely what I'm curious about, and wondering what the potential benefits could be.

A flat cone typically possess excellent off-axis response. Can certain tweeter designs/mounting techniques pair with and match such wide dispersion?

Thank you for commenting.

 

[Cal Weldon]

Not sure it will answer your question(s) but there is much discussion in these threads

diyAudio - Search Results

 

[lucadelcarlo]

Yes, I'm aware there's discussion of standard coax designs and their inherent drawbacks, but of a proposed flat cone coax? I'm extrapolating from some of those threads conclusions about how a narrow or flat profile could perform, but am seeking further input/confirmation. Thank you.

 

[Patrick Bateman]

Yes, the cone of the loudspeaker acts as a waveguide.
A flat cone would improve tweeter off axis response, but would lower the rigidity of the woofer.
Thiel uses a flat cone; look up their measurements at Stereophile and it will shed some light on the subject.

Tangband sells some flat coned drivers, which perform very well.

 

[Don Hills]

Technics did it many years ago, with their range of speakers using flat diaphragms. They made at least one driver where the tweeter was coaxial with the bass/mid (and the passive radiator used instead of a port was coaxial with the bass/mid.) They sounded OK, as I recall. (I had a set, the foam rotted many years ago.)
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