Vifa P17WJ's TL compatible?

[SteveG]

I have a set of MTM using Vifa P17WJ's, and I have never really been satisfied with the bass quality. Yesterday I received the latest audioXpress in the mail, and they have the SEAS Thor project by Joe D'Appolito featured, which is an MTM using two 7" magnesium cone woofers in a transmission line configuration. I was wondering if my Vifas would work in a similar setup. Has anyone tried this with this driver? The specs don't look too far off the SEAS.
seas:QTS- .34, QES: .39 Qms: 2.5 Vas 37L Xmax: 5mm
Vifa:QTS- .35, QES: .45 Qms: 1.55 VAS 34.7L Xmax:4mm
Steve

 

[Brett]

PMC FB1

This is a single P17 and Vifa metal dome tweet (I forget which) loaded into a TL. It has gotten good reviews so I 'spose it's possible to use a TL with this driver.

I must admit my personal preference if you use two midbasses would be individual lines for each. When I was experimenting with TLs years ago, using multiple drivers into a common volume as part of the line never worked even close to what prototypes with a single driver in the line did.

Lynn Olson, the designer of the Ariel has commented many times he has not been able to make MTMs wotk satisfatorily with drivers above 5" or so. Yet Linkwitz has apparently. I respect the work of both, and the stuff they have on their websites about developing speakers is very informative, coming at it from slightly different angles. Just meant as an observation, MTM might not always be the best solution, depends what exactly you are trying to achieve. The PMC does well with 1 midbass. Some of the other PMCs are TL loaded too.

I have not yet heard the THOR, but look at the FR of the drivers, and the crossover. I'm not terribly impressed. Metal cone DR drivers generally make great cymbals IME, but hey, YMMV.

Good luck with your project.

http://www.pmcloudspeaker.com/fb1f.htm
theres also a pdf specsheet in the download section

 

[timc]

Steve,

I build a pair of TL speakers using the following VIFA drivers,
D27TG-35-06 1" Silk Dome Tweeter
P17WJ-00-08 6.5"Polycone Midbase

Very happy with the result.

Regards,
Tim.

 

[timc]

I ment to attach this picture...

 

[SteveG]

Thanks, guys

I think I may give it a try. Supposedly, the two drivers being slightly apart is beneficial as far as mid-bass goes. After all, how much does MDF really cost anyway?
I'm not a big fan of metal cones either, but the magnesium cones look a little better than the typical aluminum cones. I don't really know how you can beat the MDT-33 tweeters I used- extremely flat, efficient, clean, natural and dynamic! I am thinking of lowering the xover frequency from 2.2k down to about 1.8K, as I hope to clean up the mids a little. I may try a fourth order also. Any thoughts on this?
Steve