Phase Plugged JX-92S

[JohnnyBoy]

I'm willing to bet that the dust cap on the JX-92S is a real handicap to its potential performance. So has anyone tried to remove a metal dust cap on the Jordan drivers?

I'm a little more reluctant than willing - but curiosity is yanking my chain. Aside from the possibility of irreparably damaging the drivers, I would think the visual impact would much like Tammy Faye Baker. I get the willy's just think about it. I'd hate to make these bad.

[pikkujöpö]

Hi there is one picture...

I would probably go with the ribbon tweeter instead.

Picture of modified JX92S

[JohnnyBoy]

Thanks, that doesn't look as bad as I thought it would. I need to source a dead driver for Planet 10 to use as a template to design the plugs. Very impressed with Dave's work for the B200.

[woody]

I could be wrong but I thaught that dust cap acted as a phase
plug.

[pikkujöpö]

Originally posted by woody
I could be wrong but I thaught that dust cap acted as a phase
plug.

From Wikipedia: "In practice, the dust cap will always add its something to the overall response of a driver since it is also a part of the moving system of a speaker".

The phase plug is used to fill the nasty empty hole,left from removing the dust cap.It doesn't add to the sound.

I could be wrong also

[Cal Weldon]

Hi woody,

I think you'll find that phase plugs are attached to the pole piece and remain stationary whereas a dust cap is attached to the cone. Part of the advantage of the phase plug is that is fills the void ordinarily found behind the dust cap.

EDIT: Posting at the same time as above.

[JohnnyBoy]

I had two pairs of Visaton B200 drivers. I sent one pair of to Dave at Planet 10 to have the dust caps removed and phase plugs designed to fit inside the void. The difference was more than subtle! Since that time many others have modified their B200's and have concurred with the report I posted last year on Audio Circle in the "Gravity Well Of A Darkstar" thread.

Phase plugs are nothing new. If you go to Planet 10's website you can read about all the happy people who rediscovered what their Fostex drivers were really capable of.

Based on my experience with the B200's, I would think the plugs would make even a bigger difference in place of an aluminum dust cap.

[Stixx]

I'm willing to bet that the dust cap on the JX-92S is a real handicap to its potential performance.

I seriously doubt that.
Ted Jordan has been fiddling with his fullrange drivers for the last 25 years or so, and they always had a dust cap. I am almost willing to bet that he tried all possible configurations but went with a dustcap to achieve a flat frequency response. With a phase plug you'll likely loose some high frequency extension, with a whizzer cone you'll have break up modes all over the place.

[soongsc]

Originally posted by Stixx


I seriously doubt that.
Ted Jordan has been fiddling with his fullrange drivers for the last 25 years or so, and they always had a dust cap. I am almost willing to bet that he tried all possible configurations but went with a dustcap to achieve a flat frequency response. With a phase plug you'll likely loose some high frequency extension, with a whizzer cone you'll have break up modes all over the place.

I totally agree. I'm just recently going to try little tweaks and test some concepts. It's only the 10K and above that needs to be smoothed out, which I think does not require much because those are not cone breakup modes, just due to some rediating pattern. the frequency re3sponse and spectral decay is already top notch. You will not easily find drivers as good as these.

[JohnnyBoy]

I'm more interested in the way something sounds than the way it measures. They are good little drivers but there is better and for less.

Whether or not Ted has ever experimented with phase plugs in his designs remains to be seen. I have yet to hear of one instance where somebody who has modified a given driver as such and didn’t hear a marked improvement. I see no reason why Ted’s drivers should be the exception to the rule. Maybe they are and maybe they ain’t, but I’m not assuming anything.

If as I suspect the JX-92S can be improved with a phase plug, the bandwagon will commence. But first I need to get my hands on a dead driver to practice removing the metal dust cap before I put mine under the knife.