WWMM with FR125S and Extremis 6.8 no compromise system.

I've got several DIY speakers under my belt. I'm now ready to start on a truely high-end setup for 50/50 music/HT. I plan on going completely active with amp1 modules from 41hz.com.

My current thought is a WWMM narrow floor stander with 2 Extremis 6.8's in a common 42l 33hz ported enclosure taking care of everything below 300hz. Above 300Hz will be taken care of by 2 sealed CSS-FR125S's.

I don't know much about time alignment. As I look at most of the high end setups here, I see that most utilize some sort of angled or offset setup. Any suggestions on speaker layout for optimum time alignment in this setup?

I'm also open to suggestions for other drivers, I chose these from reviews this board. They seem to have the highest performance/price ratio. I'd also like to not have to use my subwoofer anymore. Can the 4 Extremis 6.8's replace my Dayton 12'' DVC?


2002-11-08 6:16 am
Seattle, WA
The Extremis is a mightly little brute. I've heard the Adire LRC kit, and a pair ported can really do some bass.

Two FR125S will result in combing artfact on the high end, but it could easily be a 'measures bad, sounds great' result, esp for HT.

If you can put the speakers out from the wall, I'd consider running the FR125Ss in a bipole configuration.

Forget about 'time alignment' and work on other aspects of the design.
How far out from the wall would they need to be? The WAF of speakers more than 1' away from the wall would be too low. Could I put one to the side (left side for left speaker etc.) to get a similar effect. If I did that I'd probably go with one FR125S and one WR125S and save a little money. Could one forward facing FR125S keep up with dual extremis?

Well after a little more investigation. It looks like Adire is planning something similar in their Kit2641. However they are planning to use the WR125S with a tweeter.

I find it strange that they would design a new kit and still use a WR and tweet, if in fact the new FR would do both.

Can anyone comment on whether I can get by without the tweeter since I plan to use the FR125S?

I tried to post this to the above thread, but I've watied to long to edit... oh well. Here is a diagram of my proposed setup:


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Jim McPherson said:
I find it strange that they would design a new kit and still use a WR and tweet, if in fact the new FR would do both.

Can anyone comment on whether I can get by without the tweeter since I plan to use the FR125S?

I don't find it at all strange that they're using a tweeter. Full-range drivers have been around for decades, yet a full-range driver crossed over to a woofer is still a rare beast in commercial designs. There are reasons for that.

Your idea will work, but it will be a matter of taste. The FR125S will beam above about 4000 Hz (the waves are concentrated as in a flashlight beam). Some people don't seem troubled with this effect, especially in the sweet spot. But the NRC (National Research Council of Canada), where Energy, Mirage, PSB, Paradigm, etc, do their research, has determined that wide dispersion is an important factor in most peoples' perception of quality sound.

The major advantage of a full-range speaker design is the complete absence of a crossover. You're intending to mix genres with a full-ranger and a crossover. Even with an active XO, you will miss out on some of the directness of sound attainable with a traditional, crossover-less full-range design.

I have a pair of RAW-1F speakers. http://www.rawacoustics.com/ They're based on the WR125S, so their high-end is more limited than the FR125S. I tried them actively crossed to a woofer, as you're intending, and I couldn't live with that setup in my main system, even though I love the RAW-1F in my secondary system (no crossover). But I'm not you, and a WR125 is not an FR125, so who knows...

BTW, I think a second FR125S without a tweeter would cause more problems than it would solve because of combing (emphasis of some frequencies, absence of other frequencies, depending on listening position).

I just ordered four WR125ST's. I'm going to try a bunch of things; open baffle MTM crossed to a woofer, sealed MTM, sealed bipole MTM, 2.5-way & 3-way, using Usher tweeters and stereo subs. It's going to take me a long time to work through all the permutations and figure out for myself what I like.

Best of luck Jim, whatever you do.