Help (very much) wanted for simple quarter-wave design for cheap drivers.

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After looking in the phonebook, I found out that I live very close to Madisound's home base. (It's not in madison, actually, but darned close.)
Seeing as how I'm hoping to try my hand at my first pair of DIY speakers, I figured I may as well get something both cheap and locally availible. Some of the less expensive speakers they carry are the Hi-Vi B3N and B3S and the Aurasound NS3-194-8E; both are about 10$ and described as "fullrange".

Anyway;
I was hoping to use these in a really simple quarter wave pipe, like shown here:
http://t-linespeakers.org/projects/sampson/fe107tl.html
With a Fs of 125, I believe that the correct length would be .68 meters, or about 55 cm for the NS3-194. (The NS3 would be 1 meter, or more like 85cm after factoring in stuffing.)
However, I have no idea how to go about tapering the line. Any suggestions? I have little woodworking ability, but have experience making strange things with PVC.

Alternately, I might be able to get help with the woodworking end of things. Which of these would work best with a standard "straight tube" TL configuration?
 
There's another thread nearby here on using PVC
but making it more of a spiral.


Down at Madisound they have a nice selection
of Fostex drivers in the low/mid price range for these
single driver applications. I'm up near GB in Appleton.

Anyway my advice is use a standard design if you have
enough tools to put a box together.

An Alpha TL can be calced pretty easily and there
are designs like MLTL for the Fostex 127e that are
ready to build. The MLTL is my favorite and that's
the build I made with the FE127e ($38 ea or so.)


I have played around with 3 in. drivers and found them
wanting. The FE127e has a whole thread devoted to
a reference project. This is a good learning tool and
shows the steps in the design process.


Have fun.

lon
 
I'm not sure really little drivers are a good idea in a TL. Keep in mind they will unload below the tuning frequency. The tuning frequency will be fairly high, so you'll have massive over excursion. Consider a small sealed enclosure like this:

http://www.zaphaudio.com/audio-speaker18.html

Notice that he goes on a rant about why these little things are entirely unsuitable for fullrange use. They need a high pass filter and a sub. As a really cheap project, you could still use a high pass filter and just not have bass below 100hz. If you have to buy a sub, you may as well get better drivers.

I would vote that you spend a little more money for either the $18 Monacor SPH-60X, the $25 Pioneer BU20, or the $35 Fostex FE126E or FE127E. Take a look at Godzillas site. He has a sealed box Pioneer project, a BR FE127E project, and the Monacor in a BIB. Also look at some of the horns floating around for the FE126E.


good luck,

Paul
 
Excellent choice. They won't blow the walls down, but within their limits they'll be tough to beat. If you decide to look for some used drivers, consider sending planet10 an email, or at least checking his current auctions. I doubt you'll regret the little Fostex's. With a little creativity enclosures can be easy and unique.


Paul
 
I have used my FE127e's in a variety of builds:
open backed (as op[posed to OB) where, on the
advice of GM I cut out the backs of some small
shelf system speaks, discarded the crap inside
and magically had a fit for the Fostex. The junk
came out of a Nakamichi mini system which never
sounded right to me. Most of this had to do
I suspect6 with the company making this mini
over-tuned to bass to make them sound bigger
or something: tiny box, 25 cent sized tweeter,
small woofer with a (I think) zobel on it. The plastic
frame acted as a wave guide and I ran them that way
for quite a while.

The advice I followed for break in was to mate the
drivers face to face and run white noise from an
off-frequency receiver at full volume for few days
or a week. I made a sound deadening box stuffed with
pillow makings and turned up the volume when I
left for cab shift. ;-)


All of this came out of a question I posed like 'what's
a good moderately priced driver to see if I want to
pursue the hobby?' That was about 4 years ago.


Look around to see what you have and try mods. Pull
things apart to see how they work. That's part of the
process.


I have some opinions on the zaph projects based on
experience but these are subjective and I'd only discuss
them in mail. Mail if you wish.


Enjoy the hobby.
 
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