Speaker Design

[TEXAS TOMM]

I want to build a high efficiency speaker (X2) to complement a 3W 6A3 SET amp. For aesthetic reasons I want a round upright tube, about 300mm / 12 inches diameter with a Lowther EX or DX full range driver at the top, probably with a horn flare to couple the diameter of the speaker 22.5mm / 8 inches to the diameter of the tube . At the top of the tube I would place an adjustable angled reflector or possibly reflector cone to make it an omnidirectional speaker, consequently, the top would need to be about 1metre / 3 feet from the ground. Now here`s the problem! I don`t know that much about speaker enclosure design, I assume that what I am describing is a transmission line enclosure, and if it is only 1 metre long it would be neccessary to use some internal mechanism - probably 2 smaller round tubes, or better still, cones, folded to create an apparently longer pipe . Unfortunately my scanner is not working or I would submit a scetch. Many years ago there was a design in a magazine (wirless world?) that used a concrete pipe to create a similar speaker.

Would some kind person point me in the right direction? Web sites etc. Complete plans!

[loninappleton]

Sonotube-- that cardboard tubing used for forming concrete --has been used for some very long pipes in a design by Nelson Pass ( think.)
anyway, that was in Speakerbuilder years ago and was much taller than 3 feet.

To get the flare it may be possible to use kerfcor which is a scored plywood that can be bent.

The more traditional horn designs here like the BIB are calculated for the correct flare on the backwave and have a more traditional dimension.

Angled deflectors have been tried and I believe there is one for the Lowther but it is not adjustable-- it is just a part of the concept.

[loninappleton]

also:


http://mastersourceaudio.nsmaudio.com/jazz.html

[inutil]

do you know any link that could possibly give more details on how to make that kind of enclosure? tnx a lot

[Scottmoose]

Dear oh dear oh dear. They have a patent pending on that? I'd love to see how they can justify that one.

Anyway, word of warning: you're walking into a whole heap of trouble here.

For aesthetic reasons I want a round upright tube, about 300mm / 12 inches diameter with a Lowther EX or DX full range driver at the top, probably with a horn flare to couple the diameter of the speaker 22.5mm / 8 inches to the diameter of the tube.

For aesthetic reasons? I take it you're not too bothered about the sound quality then, because this is unlikely to be an easy design.

Even if you managed to get the basic response right, you're likely to run into a couple of other issues. a) an omni is not particularly efficient, being about 6db down compared to a forward-firing speaker due to its lack of directionality, and b) Lowthers have very limited linear excursion. So, you're looking at an inefficient type of enclosure / means of reproduction, coupled to a driver that doesn't have a great deal of excursion to compensate for it. Not a good combination.

For the actual cabinet, a simple MLTL would do the job, although your tubing might not have sufficient internal volume. For the rest, you'd have to experiment. FWIW, I'd tread carefully, and expect to need to partner it with some LF support.

[loninappleton]

Originally posted by inutil
do you know any link that could possibly give more details on how to make that kind of enclosure? tnx a lot

Well, if as Scott says the patent is applied for, prob'ly not. I don't in any case.

To me it just looks like a curiosity that a lot of clever advertising copy could be written for audiophiles.



It's very likely snakeoil.