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Tweeter quest

Dear All,

I heard a really good ribbon tweeter over the weekend. Its spurred me on with an idea I have had for some time - namely replacing the vifa tweeter in my pmc mb2-xbd-a with something of the standard of the rest of the drivers. What ribbon units would people recommend as being the best around? In addition what are the pros and cons of ribbon v. electrostatic. What are the best electrostatic tweeters currently?

So far the following have been suggested:

BG NEO3-PDR PLANAR TWEETER w/BACK CUP
http://www.partsexpress.com/pe/showd...number=264-735

Raal 70-10
http://www.raalribbon.com/products_flatfoil_70-10.htm

Raven R3.2 MMX
http://www.orcadesign.com/products/raven/ravenr3.htm#

HI-VI RT1L ROUND PLANAR TWEETER
http://www.partsexpress.com/pe/pshow...TOKEN=40236284
http://www.swanspeaker.com/product/htm/view.asp?id=226

Regards,

Nick.
brizonbiovizier
brizonbiovizier OP
124 posts
 
Hi,

The speaker is active so I can do it all in the electronic crossovers. I have room measurement equipment and software and a couple of guys on hand that design there own speakers and can help me out with the upgrade. I beleive info on the existing tweeter is in the public domain as well according to my contacts. I would crossover at 4khz.

What do you think? Any recommendations for reading?

Regards,

Nick.
shadorne's avatar
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shadorne
7,333 posts
 
Sounds risky to me...you are messing with a very high quality and well respected speaker which may be worthless after all your modifications....

Since you are a beginner at this, my suggestion would be to get a speaker kit from someone like Wilmslow audio...I remember they used to offer ATC 100 kits...not sure if they do PMC clones...

Alternatively, try canvassing PMC to offer an upgrade path to their Vifa tweeter.
brizonbiovizier OP
124 posts
 
I would mount the unit via an adapter plate to the existing screw holes so it would be completely reversible. I would keep the original tweeter. Apparently the PMC uses a modified audax tweeter not vifa as I originally stated in the active speakers - apparently the bbc loves it.
gregm
3,021 posts
 
Measure the existing audax. 4kHz isn't a bad xover point; I would choose the cheapest (i.e. Chinese) true ribbon that has the right nominal sensitivity (i.e. ~equivalent to the audax -- or higher).
Can you find out the hi pass particulars and if there's any "taming" (notches, paddings and the like) taking place?

Fo a much used and tried model, there's the Raven (1 or 2, both expensive).

The problem you may have is the ribbon not matching sonically (the perception of "speed" is often the problem) with the next drive unit. Phase anomalies can raise their ugly head... that's why I recommend cheap first.
Also beware of high wattage; ~30 is a safe max & you're best starting out with a 24db LR cut.

The PMC looks very well thought out as is, you see. What are the other drivers, BTW? Volts?
ngjockey
1,042 posts
 
Since that PMC is all active, perhaps the DEQX would help with the conversion, among other things.
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