Is this for a solid state source or tube? Like you, I don't
have an permanent long range goal but just keep experimenting.

The TLAH sounds like a Voigt pipe with an array on
the baffle instead of one or two drivers. Where is
is the terminus of the horn?

I am not using any design programs yet and am fiddling
by ear. The big test for meis organ recitals rather than
cannon explosions. And I've been trying to ecerything with
length rather than more driver hardware. One of my listeners
liked a PVC tube arrangement I put together purely as an
experiment: one PVC tube the height of the listening room
which about 10 ft. The driver was way up near the ceiling
and the terminus down near the floor and both on PVC elbows.

It did sound pretty good for those low notes but I
couldn't live with it. I chopped it down and have some
bends with less length.

But this put me on another idea: PVC is real flexible.
I could have 2 drivers on elbows (sort of looking like
a letter "F") but I don't know how that would give the
ability to shorten length and maintain the the low
rumbles.

I will get to wood someday. :-)

You're correct about the configuration, though the exact details I can't reveal until publication.

The problem with PVC is that if left unstuffed it's a very resonant speaker, a one-note if you will, and even stuffed isn't as good as a tapered line. Ten feet gives quarter-wave tuning at 28 Hz, and that's probably well below the Fs of a driver small enough to fit it, so a mis-match there.

Two drivers is the way you mention is feasible, with tuning perhaps a third-octave apart to smooth things out.

My PVC experiments are due to the fact that I only have
a few hand tools to play with. I can cut PVC with a
hacksaw, mount it on some 70 cent shelving, add a couple
elbows and a closet flange. The speaks in the 4" PVC are
RS 1197's. Real budget stuff. So without spoonfeeding me
too much, what length should the toobz be? Only stuffing I
use is behind the driver in the elbow. Any more than that
and things start to sound muddy. It may be the type of
stuff I play like organ recitals but the resonance effect
seems to enhance rather than detract.

And yes, I'm aware of the term one-note bass... the kind I
hear through the wall when my apartment neighbors have their
subs cranked. Sometimes I think they have car stereo in
the house... no audible _melody_ of any sort.

The guy that made the Voigt pipe with a discontinued Audax
full range said that most music is down in the 500 - 2000
range. If that is true just about any mid woof should
play tunes.

Wayne (hello Wayne) mentioned an Eminence 6" for the
purpose. All I see in the PE catalogue is one 6" called
100W Midrange, PE part number 290-400. I do not know
if that is the item or not.

I am watching for your website to be completed as well. ;-)

Eminence makes the Alpha 6 and recently introduced a few new 6" drivers as well. The new LA6 speakers have baskets formed so that they can be clustered close together for arrays.

Wayne

Pipes should be fully stuffed or they become resonant devices with all sorts of midrange aberrations. The idea of stuffing is that it supresses mids for a non-resonant device but the lows essentially blow right through the stuffing. Unstuffed pipes are only recommended for pipe organs where you want single note propagation.

Most music is in the midrange as far as definitive content is concerned, but it's the nuances of the low fundamentals and high harmonics that make it interesting.

I'd say the new Eminence line array 6 (available at Parts Express) leans more towards high power pro use than home; for the home I like the idea of very wide range drivers in the four to five inch range. You can get very flat response over a wide bandwidth with small drivers, and by using six or more you get the sensitivity up to where the SPL is quite adequate.

Ok thanks. PE hasn't sent me a fresh catalogue for a while.

I'm a low power sort on all counts. ;-)

Projects take forever because I acquire the background
needed pretty slowly.

I have a pair of Fostex FE127's (4.5 in) on hand. They are
in a some old Speakerlab BR cabs at about 2.5 cu. ft. I have
them set up by the computer here and everything runs through
a Yamaha RP U100 which is a small receiver with a USB connection.
Power is 30 watts per channel.