Ultimate DIY speaker design?

Troels Gravesen in his most recent "Speakers Corner" of 9/11/09 (see his website) writes of a transmission line Watt Puppy clone project he'll soon be starting. Nice drivers by general description.

I built a DIY kit last year and I'm thrilled with the result. Could you offer some more info, re: budget, size constraints, music preference etc? That would help us give a better recommendation

Steve

Jack Hammer has very poor transiant responce due to massive excursions not so good for music mostly used for SPL compitions. Plus its cone is far smaller. MTX needs far more power because its very inefficent unlike fostex 31.5 in at 96db 1 watt 8ohms it can play far louder and lower on small power than a MTX whitch is not even designed for use as a music driver. The fostex is a much better performer unless ones just wants to play notes for SPL compitions. Than MTX all the way.

These are shaping up to be some very impressive speakers: http://www.htguide.com/forum/showthread.php4?t=33995

I went down that path, it's a great hobby and the result was decent. (my wife thinks that it beats a pair of 20k speakers in our local dealer...ok, that's subjective)

It was my own design. The journey was exciting and frustrating. If you build a pre-designed kit then you won't get either.

My lesson learned:

a) it's very difficult to get things right if you don't have the equipment to measure. using your ears aren't really an option. Getting software to model the response is okay up to certain extend, but KEEP IN MIND that they cannot effectively model the baffle compensation, especially a non-conventional baffle. (i.e. how the drivers react to the box's surface).

b) almost no resale value. the drivers will sell, but your cabinet and crossover are not worth anything. I'm stuck with them for a very long time.

c) expensive drivers don't necessary mean that they are easy to work with. They are more capable but you could crash and burn with them easily (think of a Ferrai)

d) you can't really communicate with other audiophiles when you are comparing equipments. There is just no point for reference. (classic question: would XYZ amp match my DIY speakers? noone will be able to answer that question)

e) I figured the cost performance is about the same as getting a used pair of high-end speakers. You can add up the cost of brand new drivers and see if you can find a similar pair in the 'gon.