# LCRS for a HT



## erwinbel (Mar 23, 2010)

Folks, I am building two LLT (550 liter - 13 Hz) to house the Maelström 18". 
Pic from today:








I had all sorts of idea's for the Left & Right, the Center and the Surround speakers. The room is large @ 5,000 cubic feet. Main function is HT, but there's a kitchen and dining table also. If money were no object, I'd get the Bowers & Wilkins CT800 system which cost crazy money. I thought I'd settle for the more reasonable CT700. But in the end, my curiousity and aspirations are a bit to much to put silent! 

Please give me your opinion about the DIY transmission line speakers from Troels Gravesen, the TQWT. They come in various sizes and the same front drivers are used in the 2-way QUATTRO, which could serve as a center (with short feet than the design). I want to do a proven design that works. Wood working is no problem. I believe the TQWT design is as far away from a boomy box as you can get without going to an open baffle (which I have in the form of the Jamo R909). In this way, it shares a lot of the idea from a LLT, don't it?

QUATTRO:









The biggest design: the TQWT with two 12 inch woofers added on the back. It's about 5x2x1 feet! The standard TQWT is only about 2/3 of that. I'd like the big ones for the front LR (if I can fit them, it should work) and the standard 2-way for surround. 

DTQWT-12








Prices are about €400 for each 2-way kit and about €700 for the big kit (without cabinets). Shoot your thoughts, please!


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## GranteedEV (Aug 8, 2010)

I wouldn't be surprised if the Troels high efficiency stuff sounds absolutely excellent for HT especially in dynamics.

With that said I think if you've got the money you're "probably" better off with the Gedlee or Econowave stuff.


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## erwinbel (Mar 23, 2010)

GranteedEV said:


> I wouldn't be surprised if the Troels high efficiency stuff sounds absolutely excellent for HT especially in dynamics.
> 
> With that said I think if you've got the money you're "probably" better off with the Gedlee or Econowave stuff.


Never heard of those! I will look into it. But one of the other price advantage with buying EU is to avoid the extra 30% markup for duties and VAT (other than extra shipping cost). The ones you name sound American?


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## Zeitgeist (Apr 4, 2009)

GranteedEV said:


> I wouldn't be surprised if the Troels high efficiency stuff sounds absolutely excellent for HT especially in dynamics.
> 
> With that said I think if you've got the money you're "probably" better off with the Gedlee or Econowave stuff.


I'm probably misunderstanding the econowave "stuff" - but most econowave projects that I've seen just involve a (sometimes reused) 12" woofer and a compression horn (with a CD waveguide) ?

I've read a lot of good things about econowave - but didn't think that they were on par with speakers that used better quality drivers?


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## GranteedEV (Aug 8, 2010)

Zeitgeist said:


> I'm probably misunderstanding the econowave "stuff" - but most econowave projects that I've seen just involve a (sometimes reused) 12" woofer and a compression horn (with a CD waveguide) ?
> 
> I've read a lot of good things about econowave - but didn't think that they were on par with speakers that used better quality drivers?


constant directivity. something like the drivers used in the troels project with those crossover points just won't have it. there are only a few optimal polar response characteristics out there and that is what makes econowave good. sometimes we put too much stock into how well a driver performa anechoically on axis and forget how the speaker is going to couple to the room.


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## Zeitgeist (Apr 4, 2009)

GranteedEV said:


> constant directivity. something like the drivers used in the troels project with those crossover points just won't have it. there are only a few optimal polar response characteristics out there and that is what makes econowave good. sometimes we put too much stock into how well a driver performa anechoically on axis and forget how the speaker is going to couple to the room.


Thanks! That makes perfect sense.


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## vann_d (Apr 7, 2009)

Pi speakers seem to me to be a better option than the econowave. They use high quality drivers and CD design. Kinda ugly though. I was set to build a pair of 4Π's but balked because of the size.


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