Modification of a driver

[kaan]

I found this article describing the modification of a scan speak driver and while I find it very interesting I am not sure that I have the guts to try it myself.
Is there any of you that have tried this or similar modifications?
If so please provide links and stories

http://www.steenduelund.dk/scanspeak8554.pdf

[Cal Weldon]

We get to see a lot of the phase plug, bucking magnet and cone treatment here but the thread spider is a new one to me. Very interesting.

[DcibeL]

I'm confused. There's no strain relief (ie the wavy shape of a spider surround), so I would expect a thread to snap at high excursion, which would likely destroy what's left of the speaker.

I would say that if the frequency response and/or Q values of the driver you have aren't what you want, find another driver rather than doing a bunch of scary modifications.

[sdclc126]

Originally posted by DcibeL
I would say that if the frequency response and/or Q values of the driver you have aren't what you want, find another driver rather than doing a bunch of scary modifications.

I agree - especially since the current stuff from Scan Speak is so good.

While we're on the subject, does anybody know why SS doesn't use phase plugs? I don't think I've seen any of their drivers with them. Most of the top end makers use them in at least a portion of their product lines.

[tinitus]

10 years ago I replaced spiders with threads on a SS 6" and phase plugs too ... no big deal ... and didnt help the driver much

BUT lately I have removed dustcaps on SS 8" woofers in a 3way ... no phaseplugs this time but new dustcaps made of airy foam ... great improvement from the bottom to the top

Whenever possible mr. Duelund used half a tabletennis ball as dustcap ... one reason why the SS 15W looks like that ... but others have used very round dustcaps before ... but please, mount it where the voicecoil is joined to the cone and nowhere else

I am building my own 6" driver at the moment ... and now a "thread-spider" comes in handy

[Ron E]

Ok, so he made a driver with a looser suspension.

Big Deal. It looks like a recipe for driver failure. Model any driver and change Cms, note what happens.

I bet it distorts more than the original driver and sounds different. Seems like a classic case of I-did-it-itis -- doing something and deluding oneself into thinking it made it better.

The flow diagram shows vortex shedding, not solitons. Vortex shedding, being a velocity sensitive effect, doesn't depend on pressure so much, as described in the text, especially since sound pressure is a gnat on an elephant's bum compared to the 101325 Pascals of atmospheric pressure. The whole writeup is moronic and ill-justified - bonehead audiophiles will believe anything vaguely scientific if it comes from a "known" entity....

[sdclc126]

Originally posted by Ron E
Ok, so he made a driver with a looser suspension.

Big Deal. It looks like a recipe for driver failure. Model any driver and change Cms, note what happens.

I bet it distorts more than the original driver and sounds different. Seems like a classic case of I-did-it-itis -- doing something and deluding oneself into thinking it made it better.

The flow diagram shows vortex shedding, not solitons. Vortex shedding, being a velocity sensitive effect, doesn't depend on pressure so much, as described in the text, especially since sound pressure is a gnat on an elephant's bum compared to the 101325 Pascals of atmospheric pressure. The whole writeup is moronic and ill-justified - bonehead audiophiles will believe anything vaguely scientific if it comes from a "known" entity....

So how do you REALLY feel about it, Ron?

[tinitus]

I should ad that he often worked on improving carefull selected and quite cheap drivers

Its just as big a delusion as to think that a driver is as good as can be just because it comes from a well reputed compagny ... or because its expencive

At one time he modified a CerwinVega to such a degree that it was the best many people had ever heard

[Magura]

Well, if you pay attention to what Duelund has made over the years, you will see that is't best described as hit and mis backed with loads of hooey.

No offense meant, but you should take his "papers" for what they are. I recon he has made a few things that actually worked, but most of the stuff he played around with were a real far fetch.


Magura

[Cal Weldon]

I once cut out sections of the spider of a couple drone cones to get them moving a little better and further but threads seem a bit suspect to me.