Exploring Purifi Woofer Speaker Builds

  • Like
Reactions: mordikai and Juhazi
Likely peak to peak and not one way xmax.

16mm one way linear excursion, 70mm peak to peak before damage, according to various sources. 7cm one way could be ruled out from visual observation alone, as it would require a much larger surround.


The surround is all new

Afair the first time I've seen such a design was on the 18Sound 6ND430, for the purpose of reducing surround resonances.
 
Not likely. Confirmed. 35mm one way.

This much (or more) excursion and variable voice coil winding has been around for awhile, and double inverted suspension has been around for awhile.

35mm one way, not 70mm one way. I said the 70mm/7cm was likely peak to peak, and you confirmed I was correct. Why would you say "not likely" to my response? Or were you agreeing with me?
 
Fostex have been doing it for a long time.

d2.jpg
 
does anyone know if fostex said what they were doing 'it' for.
We have adopted our original foam drabber as the edge material, which was jointly developed with a material manufacturer. It combines the texture of a solid rubber edge with the lightness of a cloth edge, and together with the UDRT shape (*2), suppresses resonance.

he edge supporting the diaphragm has a UDRT shape that allows the front and rear amplitudes to be close to symmetrical, contributing to accurate and clear reproduction of the sound field.
Not really, it has a Purifi surround.
The motor structure looks fairly basic, a large FE mag/deep gap. with a T-shaped pole piece and 2 alu. demod rings.
Will allow high excursion. But with more nonlinearity then a Purifi motor.
 

Attachments

  • Like
Reactions: ErnieM
The centre polepiece in the Dali motor looks like Dali's proprietary pressed ferrite.
And permeability of Ferrite is quite high.
Could even be as high as Iron in some cases, although that is doubtful for this purpose.

Purifi goes a long way to try and mimic a "air core" in they're motor structure.

The gap is small.
The alu. demod rings are very different in total size.


But only a proper Klippel test will reveal.
 
Last edited: