New Enclosure for vintage 12", need opinions

[sushizen]

hi guys,

i am thinking of building a combination flared transmission line fronthorn to mount some vintage 12" drivers. the t-line will be exponentially flared, tuned at quarter wavelength of 40hz, or closest resonance figure. it is loosely based upon the "king cobra" spiral transmission line by tetsuo nagaoka, combined with a 50's vintage inspired fronthorn.

i am attempting to match the backhorn with a frontal flare whose cutoff frequency approximates one octave above the t-line's cutoff frequency. is this a correct manuever? say, if driver cutoff was at 40 hz, first octave horn dip would be at 400 hz; could this be be "taken care of" by the front horn? i also hope to stuff the enclosure adequately to dampen the dip. my question is this: is this style of design permissable? am i screwing things up by flaring the backhorn and fronthorn to the same cutoff frequencies?

has anyone ever heard of building a backhorn/t-line with a fronthorn attached to it? i am hoping to get the best of both worlds with the bass support of a rear-firing t-line/ backloaded horn coupled with a nice fronthorn for presenting the upper-midrange. HF, as with any old coaxials, shall remain up to the gods and the quality of driver i pick.

here's a picture of what i mean. thoughts?