Theory behind Dunlavy and Lipinski speakers?
 

I've read quite a bit about Dunlavy's and now Lipinski's being used in studios. I think I understand about the WMTMW design, it being very similiar to the idea of the MTM D'Appolito arrangement. I also understand about Dunlavy using first order crossovers. I understand about using sealed enclosures. What I definitely don't understand is their use of felt and foam around the tweeter in particular. Is it purely a way of trying to reduce diffraction or is there some kind of horn loading of these designs or something else? I'd like to know. I can not recall seeing any discussion about it online. Anyone?

Re: Theory behind Dunlavy and Lipinski speakers?
 

This is what it is if I'm not completely mistaken. No horn loading or anything like that.

Note the tweeter is inset from the mids. That helps time alignment, which is fairly critical with first order crossovers. It also means you need to keep side radiation from the tweeter from bouncing around the cabinet walls, hence another reason for the felt.


Cheers,
Francois.

I've read John Dunlavy's white papers on his design principles.
Dunlavy (and Duntech) speakers have stepped baffles, which in conjuction with the first order filters, create a linear phase response. i.e the waveform shape is preserved. Because of the steps in the baffle, severe diffraction would occur, and so heavy felt damping is applied to absorb the sound waves before they hit the edges. It also reduces diffraction with the sides of the baffle.

Take a look at www.duntech.com.au , the company John Dunlavy founded a few decades ago in Australia, and is still operating.
Also see http://www.vaf.com.au who use a similar principle.

Yes, some guys at my university were building Duntech-clones and explained the reason for the inset.

How can one analyze the time alignment of crossovers/drivers?

Landroval, John Kreskovsky has papers in his website regarding the subject.

Shame that Dunlavy Audio Labs went belly-up. I wonder if Dunlavy is still active (in)directly at Duntech. Those Sovereigns must really sound good. Boy I'd like to hear Telarc's Stokowski Sound CD-80129 through a pair of those :D

You can analyse it in the time domain using COOLEDIT 2000 or similar with added functions. Its the acoustical response we are after. But what happens once we are in room?


http://img291.imageshack.us/img291/2...example0bc.jpg

http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=82145
http://www.triodefestival.net/member...vers_etf04.zip

Thanks everyone. I am aware about the stepped baffles. I remember reading awhile back, before I know much about speakers, where someone implied that there was more to the felt than just diffraction reduction. That's why I asked.

Have any of you messed with felt like this? Given the inset drivers and the shape of the baffle, it seems to me that reducing diffraction would be a monumental task, with felt or without.

f4ier, Dunlavy didn't exactly go "belly up". They were sold to a larger company that was hoping to make more money with speakers by increasing production and/or productivity or something like that. The buyer got Dunlavy and then realized it was cheaper for them to just close down the factory then to put any more money into changing Dunlavy. At least that's what I heard. Dunlavy was a profitable company and didn't go out of busines by going bankrupt, as far as I know.

I found an archive of Dunlavy's newsgroup postings awhile back, here I think: http://home.austin.rr.com/tnulla/ , but it seems to be gone. Does anyone know if it's still up somewhere? Google doesn't bring up any working links for me.

just to share to may experience...

I audition a system with big Dunlavy speaker with WMTMW...

and at the same time there is a big Tannoy coaxial speaker (wider than the Dunlavy, which is about 2meters tall, and 50cm wide)

and to my amazement... Dunlavy sound a lot better than the Tannoy...

Dunlavy with multiple drivers simply disappear... (just like a single source speaker) and throwing a very spacious soundstage...

---
David

Imaging
 

A friend of mine has a pair of Dunlavy IV/A's. The drivers are good quality Vifa's and such, but hardly remarkable these days. The cabninets are huge. Nevertheless, the "sweet spot" is only about a foot wide! You've got to sit smack in the middle to hear them at their best.