The ultimate DIY...pictures of my homemade driver and enclosure

[zagisrule!]

Hey guys!

I was getting a coke from the fridge the other day and got an idea...

There was a strong round magnet on there that made me think. I went back to my "lab" and found an isoprpopyl alcohol bottle that was nearly empty. Looking at it more, I saw that the top of the bottle could make the perfect speaker cone. It was light and stiff, the properties present in any good driver's cones. The bottom of the bottle could double as a basket and enclosure. I got to cutting, and my woofer cone was soon ready-to-go.

Not much later I had my basket done, with a hole so as to act as a ported enclosure for my driver. I super-glued the magnet from my fridge to the bottom middle of the "basket" and viola! A perfect basket. I wound a 4-ohm voice coil from some spare 30-gauge Radio-Shack magnet wire I had lying around, and now the issue was in creating surrounds and a spider system.

The spider consists of three rubberbands that suspend the woofer cone slightly above the magnet to give clearance and adequate suspension firmness. The surrounds are simply 3M "Super 33" electrical tape, which will give the best sound (I also tried a few other brands when I had the design tweaked, but the sound of the 3M is superior due to it's elasticity). I have the tape wrapped in such a way as to keep the tape from sticking to itself, but I can't disclose how that is done at this point

I ended up with a complete midrange woofer assembly, which I proceded to test. I found that the sound was spectacular, especially in the mid-high frequency ranges. Bass response was great as well, but I did not like the loose, rumbling sound that the unit produced from the loose suspension and ported enclosure. I estimate bass response to be down to about 20Hz, but again the ported enclosure really made the unit rumble like it did.

Test number 2, with a stiffer selection of ruber bands led to better results in the bass dept, with tighter bass and better midrange.

By now I decided to add a small enclosure to the unit where my port hole was, so I took another brand of bottle and fitted it to the hole. I cut the bottom off of the second bottle, trimmed it, and suspended it to create a passive resonator in the bottom. The enclosure is now effectivly a sealed box, with a passive resonator.

The third test run was much more effective, and the speaker sounds wonderful (suprise! ). Overall, I am very impressed with the sound, I am hearing details of my CD's that I have never heard before. The only negative things about the unit is that it is fairly inefficient, and requires about 10-25W for room-filling sound, and I am concerned about the longevity of the high-quality electrical tape surrounds. After a few hours of listening, the tape starts to loosen and I have to press it back on.

The magnet is the heart of the system, and I think that it contributes greatly to the effectiveness of the system, because of it's magnetic polarity and strength. I have since played with other types of tapes and speaker wire, which brings up another topic. My triple-braided speaker cable from the wrapping wire sounds great! I only spent a few hours making it, but the sound is spectacular! I support the bottom (with the resonator) with some pieces of thick copper wire.

I am attaching photos to document the ultimate in DIY speakers: Homemade drivers using bottles and refrigerator magnets, as well as another bottle to create a sealed passive resonator enclosure.

I will reveal the type of magnet (manufacturer, shape and color) once my patent comes through, but it is available at Wal-Mart if you want to take a guess and experiment.

I also added a bit of decoration to to cones, adding my ZR (see my username )




-Matt

Here is a picture of the overall unit stood up outside:

[zagisrule!]

Here is the bottom of the enclosure and the passive resonator....

[zagisrule!]

Here is the woofer front....

[zagisrule!]

And here is the the rear of the whole thing...I used a "Family Dollar" bottle for the enclosure. It also shows my solder terminals, I only use a fine grade of Japanese solder, because the rosin does not corrode and distort the sound.

[pinkmouse]

Top hole old fellow, an engineering achievement that reminds one of the works of Stephenson and Brunell.

[GrahamnDodder]

"30-gauge Radio-Shack magnet wire"???

I would have just strecthed a few pennies, of course...

(Kidding - cool project!)

GnD

[zagisrule!]

Originally posted by GrahamnDodder

I would have just strecthed a few pennies, of course...

Hmmm....

Time to get that vise and the pliers out...I have some spare change in my pocket.



Perhaps I should just did a hole and mine copper in my own backyard? Perhaps "natural copper" sounds best?





-Matt

[GrahamnDodder]

Noooow you're gettin' it!

[sreten]

Not impressed. I'm still looking for something I can plug into
my walkman that produces vomit inducing levels at 7Hz and
is still compact enough to keep the missus happy.

I'm sure it can be done, you don't have faith, sreten.

[Paradise_Ice]

That reminded me of my younger days making woofers from bricka brac and alsorts, its fun and its keeps you happy,
Well done