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.

 

Buy some proper loudspeakers - don't try to screw around with flawed ones.

 

replacing drivers like this would surely play hell with X-over points/voltages/impedances ..

 

The system is active so I have control.

 

If you're going to go down that route, would you rather not start out with a clean sheet design?

 

Nah - I really like the pmc unit and the mid and bass drivers are superb. I think ribbons and electrostatic tweeters are a step forward though.

 

I often find myself prefering a ribbon tweeter to a silk/paper/metal cone tweeter.

For example Dali Helicon is a nice sounding speaker I think. http://www.dali.dk/uk/page288.aspx?sub=213&prod=453

You may find that the size/shape of a ribbon tweeter to be non compatible with the shape of the tweeter in your PMC.

You may also of course find the ideal crossover point to be different - and although your active crossover may allow you to adjust this, what if this causes the mid-unit to operate outside of it's ideal operational parameters?

Would you risk disfiguring (and therefore de-valueing) your expensive speakers?

 

There are no flaws SM - just an area for some improvement as with all speakers. The vifa unit does not disgrace itself but better ribbon tweeters are available.

Didnt you get rid of the jbls?

 

Yes so I am looking for somthing compatible or that can be mounted on a plate then mounted onto the existing mounting holes...

I would crossover at 3.8khz - which is what the existing unit does. This is quite high so it should be ok I guess.

 

Something that can be improved is flawed by definition.

If you want better treble, listen to Adam monitors, to Westlakes, TAD's and others. Don't waste your time on PMC's. Do you have any idea how much the mid and bass would change with a more extended treble response?

 

I added a pair of Tannoy supertweeters to my broadband speakers, xover at 18 khz, and I like the result...

 

Everything can be improved therefore everything is flawed. So it becomes an issue of which compromises are preferable. The pmc treble is good - for a conventional tweeter. However it is not outstanding as the mid and bass units are so it is something I am interested in pursuing to get even better results.

I will of course have to do more research, however given the active crossover and the deq (or some digital crossovers) - I am sure it can be done.

Doubtless I will listen to Adam, Westlake, meg, TAD etc at some point. If I prefer them I will swap.

 

The time spent on the former would be better served by actually doing the latter.

 

Hmm those raal tweeters look rather good...

 

The tweeter in the MB2 active is actually an Audax one. Its a TW034X0 modified by PMC. One of the mods is to make it extend higher to over 20KHz. It is a very good tweeter and certainly a fair bit better than any of the other tweeters in PMC gear.

However, I agree it can be bettered by some exotic designs.

The circular one you mentions is a possibility but it only extends down to 3.5KHz so the crossover wouldn't work at all well at 3.8KHz. The current tweeter extends down to about 1KHz before rolling off so the crossover at 3.8KHz will be designed such that it expects the tweeter to have a flat response over most of the roll-off, about 2 octaves below the Xover point. So as long as it does that, you can use the Xover to adjust for efficiency and beyond that use an L-Pad if necessary. It should work fine.

I have looked and looked at drivers like this for my speakers. The RAAL really is the bogs dollocks and it is smallish as well. The Hi-Vi like Thorstens is pretty large and might not fit above the midrange.

What do you mean by electrostatic tweeters? Do you mean planar magnetic like the Hi-Vi ones?

Yes the RAAL tweeters look good, and they are not afraid to publish measurements. I asked for some and they went to the effort to make them for me.

 

No I mean electrostatically driven like my headphones.

Yes the raal specs look the best - how much do they cost for a pair?

That bring the mb2 up to state of the art in all areas - though S&M is sure to squeal if I say that. Where did you find out it was audax?

 

holy ****..

 

What the fudge is that?

 

mind you. I'd still prefer some TAD or Westlakes.


One day they shall be mine, oh yes, they shall be mine.:JOEL:




*edit* it's a honking big Adam Monitor.

 

Adam monitors use AMT's (air motion transformers) the problem with them is that they generally start to beam above about 10KHz, and more than even someone after a directive tweeter might want. I do say generally, I have not seen directivity specs for the Adams. They are good, but not the best. Check out Mundorf.

I have not seen any electrostatic tweeters. Maybe because they would need a power source, no one thinks it is worth doing?

Nick, the tweeter is quite a famous one liked a lot in the past by the BBC, but in its un modded form it had trouble getting above 17-18KHz. They liked it for its vocals.