RS180 vs Extremis vs P17REX

[Shonver]

I'm looking for some advice regarding which driver to use. Application is midrange duty from 200Hz to whatever upper frequency works best with a good 1" tweeter. Enclosure is 7 litres, sealed. Crossover will be active.

The original driver fitted is a SEAS P17REX-type driver. I have the Extremis 6.8 and Dayton RS180 drivers on hand to substitute in place of the tired-looking P17REX. But I don't want to sacrifice sound quality for looks. What I want to know is: which of these drivers would be the better performer in this application?

Assume that I am capable of successfully design the appropriate crossover...

[JonMarsh]

Assume that I am capable of successfully design the appropriate crossover...

That last sentence is the deal clincher, of course.

The RS180 has a fairly decent bottom end and low midrange distortion up to about 1500 Hz. It's definitely more capable than the P17REX, BUT, it has upper end breakups that require taming- look at some of the designs here in the Missions Accomplished section to get an idea.

The Extremis has some resonances right in the midrange- it was originally designed as a long throw six, primarily to optimize bass response, though the motor has more electrical excursion capability than the suspension (I know, I was an early buyer and tester- and seller- of that driver). It's also a bit low on the sensitivity side. Best efforts with it seemed to be compact three ways with a dome midrange.

A Peerless Nomex or Vifa unit might be a lot easier way to go, with less issues to tame on the top end.

[Shonver]

Thanks, JonMarsh.

I do believe that I am capable of suppressing the RS180's breakup modes. Right now I have the North D28-06S and RS28AS-4 (unchambered, shielded Dayton) tweeters available, but I'm willing to get hold of a SEAS 27TDFC if neither of the aforementioned tweets are up to the task. Any thoughts on tweeter options?

[Finleyville]

Although I do not have even a glimmer of Jon's expertise, I thought I would add my $0.02 anyway...

I am using the Extremis in my car actively crossed over. I only have it playing from 60 to 300 Hz. (I use a modified Vifa TG-9 for midrange duty) It does extremely well in this region. However, I would only consider it a mid-bass driver not a mid range. Plus, yes, it does require a lot of power to sing. I have 250W going to each of mine and they love every drop.