Instructables
Hi guys, this is my first Instructable and I will show you how to build some efficient speakers with just a little of duct tape and copper wire. I hope you enjoy! (Forgive my bad english, I will try to be as clear as possible)
 
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Step 1: Materials

For this instructable you will need:
- Insulated copper wire (as thin as possible, a little more than a human hair)
- A pair of earphones
- A powerful magnet

and obviously......

- THE DUCT TAAAAAAPE (I used some Masking tape but any kind of tape is fine. the important thing is to have a sticky surface on which to paste the coil)

Step 2: Tools

Picture of Tools
For this instructable you will just need:
- Scissors
- Lighter

Step 5: The cable

Picture of The cable
To connect the speaker to the signal source you will need a stereo cable. You can buy one at http://www.radioshack.com or You can obtain it from a pair of headphones, as I did.

Step 6: Cardboard support

Picture of Cardboard support
DSCN7269.JPG
DSCN7270.JPG
If you want you can build a small cardboard support, for aesthetic reasons
lukedwards1 month ago

I'm not sure what I could be doing wrong. I've made 3 so far and none of them make a sound!? Any help? I did it the same as above, only I used duct tape instead of masking tape. Even tried using a hard drive magnet like above, still nothing. I thought it would be a neat project to do with some kids but not if it's not going to work. Dissapointed...

Doctor90250 3 months ago
that is really cool... thank you. I'm getting ready to post my first as well.
diamondmine6 months ago
What gauge wire and any suggestions where to get it?
Congratulazioni! 2 italiani fra i vincitori!!! :D
ahahaha grazie!! e ti faccio i miei complimenti per il settimo posto :) ti sono già arrivati i premi?
Grazie mille!! :)
Allora, siccome l'Italia non potrebbe partecipare ai concorsi ho dato l'indirizzo di un amico che vive negli Stati Uniti e so che il pacco gli è già arrivato quindi uno di questi giorni me lo manda a me...però è frustrante perchè ci mette il doppio del tempo e costa anche! Avevo la tentazione di provare a mettere il mio indirizzo ma alla fine ho preferito rispettare le regole per sicurezza. A te è già arrivato? Dove te lo sei fatto mandare?
Peris The Majestic (author)  lindarose9212 months ago
Si, non capisco il perchè di queste complicazioni.... me lo sono fatto mandare in germania da un mio amico, in modo da non pagare tasse doganali (non mi farebbe molto piacere dover pagare magari 50 euro o più per una maglietta...). Il mio mio amico mi ha detto che è arrivata senza problemi, aspetto che arrivi a me ora :)
L'ho chiesto tempo fa e mi hanno risposto che è colpa delle leggi italiane (ti pareva...). A proposito, l'altro giorno ho avuto l'onore di essere intervistata come Featured Author e grazie a questa intervista ho trovato altri italiani su Instructables! Ho scoperto che ad uno di loro il premio gliel'hanno mandato in Italia tranquillamente quindi se avrò la fortuna di vincere qualcos'altro proverò a mettere il mio indirizzo, speriamo in bene! :D
MancaveNL1 year ago
Awesome project! I blogged about it on my DIY tech/electronics website, hope you like it http://mancave.conrad.nl/speakers-van-schilders-tape/. Now let's see if we can get some Dutchies to build this as well :)
Peris The Majestic (author)  MancaveNL1 year ago
Thank you very much! i'm glad you liked it :)
agm881 year ago
heck if it works with any tape ill try it
racoontnn1 year ago
I think that to do this stereo unit is a bad idea. This is a fun toy, designed to demonstrate the principle of the speakers, and electromagnetic forces. And to make two copies of it to show - it is not necessary.
goldy1 year ago
one question, why you're doing it mono? Will it work if you make 2 speakers and hook them independently to each headphone channel?
Peris The Majestic (author)  goldy1 year ago
i do it mono beacuse I need a powerful audio signal to run two speakers at the same time and i do not have a powerful enough amplifier. anyway I'm sure that would work :)
connecting the left and right channels in parallel is a very, very bad idea assuming you intend to not let the smoke our of your amplifier.
funkytaco1 year ago
mriev is being constructive with his criticism. Not all of us are expert electrical engineers, so it is good to understand what challenges we will have to deal with. I also would not want to ruin my synthesizer I was hoping to use this with that I built myself using a circuit board and parts found online.

So, thank you, author and thank you, mriev.
Peris The Majestic (author) 1 year ago
I do not see the point in continuing to argue for a mere trifle, really. I thank you for your interest, but it isn't worth it. have a nice day :)
deanz1 year ago
I would have never know this was possible without this instructable so a genuine thank you for improving my knowledge.
mriev1 year ago
I don't have to try it, I have over 45 years experience as an electronics technician, and a senior electrical and instrumentation designer. First, the impedance of such a design would be well under 2 ohms at lower frequencies, and most amps simply aren't designed to drive impedances that low. As for efficiency, in order for it to reach any reasonable level, the entire voice coil would have to be in a fairly strong magnetic field, which could not be the case with the setup you showed in the pictures, and third , with an area that small and no enclosure, the frequency response would be extremely limited.
It's just a simple project, but you shouldn't have called it "efficient" and you should have mentioned the limited frequency response. The critical issue is the very low impedance of the design, should someone hook it up to an expensive amp or stereo receiver, it would most likely damage the amplifier section, So, either a 4 ohm resistor should have been included in series with the speaker, or a warning not to hook it up to any amplifier that you didn't want damaged. If you want to revise your project to include the 4 ohm five watt resistor in series with the voice coil, and remove the comment about it's being efficient, I'll withdraw my comments and delete my posts>
deanz mriev1 year ago
straight off wiki... ha ha "lower impedance headphones will tend to be louder and more efficient, but will also demand a more capable amplifier"
Peris The Majestic (author)  mriev1 year ago
i'll modify the project as soon as possible. in the meantime I'll put an ad to warn of the risk of damage, even if it seems to me unlikely. for sure I do not want to have on my conscience the broken amplifiers of some unfortunate guy. would be a shame. thanks for the advice, have a good day
darqdean1 year ago
Very good - well done. To be more efficient your magnet needs to be as big as your coils of wire, (or your coils as small as the magnet), because any wire that isn't in the magnetic field isn't going to move - and the more coils you can get in the magnetic field the better it will be, so thinner wire will help. Also I'd think about using a small resistor(say 6.8 ohms) in series with the coil to save damaging your amplifier. Good start though.
Your comment about the magnet pole area and coil size matching is correct. But there is much more detail that needs to be attended to, to get the speaker to work well. The current (flowing through the wire) must be flowing all in one direction in the region of a magnetic pole (in order that the forces add up and not cancel, or push in the wrong direction). The magnetic field needs to be parallel to the plane of the speaker sheet in order that the force is perpendicular to the sheet. For the magnet you show in the photo, there are 2 poles at opposite ends of the magnet. (The magnetic field comes out of one pole, arches through the air, and goes into the other pole).  The region between the poles (over the center of the magnet) has the parallel field you need. The wires on the sheet need to be perpendicular to this field. Get, say, 6 of the magnets, and arrange them in 2 rows. Each row needs to have the magnets set side-by-side with the north poles along the same side.  The second row is set beside the first, with the north poles facing the north poles of the first set (fasten them down; they will repel!).  The coil will want to be rectangular shaped, aligned with the magnets behind, with the turns going down the row, between the poles of the first row, and the turns going up over the other row.  no turns should go directly over the poles (there will be no useful force developed there).

To get a feel for what's happening, get a DC supply (a couple of amps at a low voltage will do, you can use a D-cell) and set up a loop of fine wire.  Hold the loop so it dangles (and can move with delicate force).  Bring it near the magnet, and watch the movement when the current is switched on momentarily.  If it is passed over the pole (near the ends of your magnet), the wire will move sideways (which is useless for speaker action).  If it is passed over the magnet between the poles, the wire will move toward/away from the magnet (the desired action).  The magnets must be "phased" or the forces will cancel instead of adding up.

If you on purpose build the coil very flimsy (such as tacking it to a barely-stretched stocking), you can suspend it over the magnets and apply DC to verify that all the forces act in the same direction.  Then build an identical one on your tape surface.  Be sure to mount it in the same relative alignment to your magnet structure as before.  Your speaker will work way better!  You will need a whole bunch of magnets.

I have drawn a diagram, both a facing and an edge view of the speaker.
Brilliant
Treknology1 year ago
I wouldn't endorse this with the word "efficient" but, you have definitely come up with a simple project that demonstrates the fundamentals of a dynamic speaker in a way that people can see, hear (and feel) the principles in action. Very nice.
Here's an alternative idea (note: idea, not tested): instead of tape, an appropriate (thin) piece of paper sprayed with an adhesive (e.g. 3M 77 [always great]); then once the copper is applied, the adhesive will dry. If this works, it opens up TONS of possibilities form the speaker cone material. Construction paper, onion skin, you name it!
would be great! I plan to change the design of this project and your idea is very useful, thanks :)
I must say, I did have my doubts about this (mostly b/c I don't quite understand speaker fundamentals) but the video sold me on it! Definitely will be constructing one of these great speakers! Thanks for a wonderful -ible!
mriev1 year ago
I actually agree with Inorooz, except for the fact that its impedance would be so low as to damage amplifiers, and his comment that it was efficient. The impedance is a critical factor, and if someone tried it and hooked it up to a stereo receiver or other fairly expensive amplifier, the damage done would be rather expensive to repair, so I felt compelled to post a warning.
mriev1 year ago
Planar speakers have been around for many years, Peris's design is a very simplistic version, but the critical difference is that those speakers had a voice coil much larger than Peris.s, resulting in higher impedance. The illustration shown above only has a few feet of wire, not nearly enough to raise the impedance to a suitable level. Magnepan made some very good planar speakers, but they are very large. A planar speaker is a dipole radiator, that means that the sound coming from each side is out of phase with the other, and unless the panel is very large or the radiation from the back of the speaker is contained by an enclosure, low frequency response will be severely lacking. And the mass of Peris's diaphragm with the wire (most planar speakers have an etched diaphragm, much less mass than wire) is too high to allow good high frequency response.
lnorooz1 year ago
I'm surprised by how many negative comments you have, I don't think you really deserve it, especially for your first instructable (good for you!). This is a fun little experiment; I've actually played around with it myself a lot and I think you did a great job with it. :) Thanks for sharing!
bricmic1 year ago
Yes, Polyplanar did the same thing on a sheet of polystyrene in the 70 ~ 80 '. For "mriev" At Polyplanar impedance was 4 ohms, and the coil more quark, bandwidth "happening" in HIFI 20-16KHz +-3dB. Sorry.
Mortarius1 year ago
This design is certainly simpler/cheaper than the coil around a magnet one, but are there any downsides?
Peris The Majestic (author)  Mortarius1 year ago
well..maybe does not have a real practical application .. I mean, it's just an interesting object to show or an experiment to do for fun. Anyone who wants to listen to music, use of professional speaker or headphones, not a speaker of masking tape. :)
that is masking tape, not duct tape.
i know. i wrote it in an older comment. but thank's for the correction
Beware : Duct tape is far more massive than paper masking tape (hey guess why most speaker cones are made of paper?) So I would suggest people do as he does, not as he says ...
hard disk ? can i use magnet
amansell11 year ago
this looks much easier than the other speaker tutorials, i will have to try it. You did a great job with explaining.
indigo4011 year ago
http://www.instructables.com/id/Speed-Stick-Power/
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