DIY lo-fi speaker element

[Mursu]

I am intrested in building speaker element for my lo-fi experiments.

What is the simplest way of building your own speaker element... and if posible with standard household items or something other easily awailable materials.

Distorion or bad signal to noise ratio is not an issue. I really WANT to have unlinearities and audible distortion. As long as speech is even remotely understandable there can't be too much distorition.

I am intrested in diffirent type of elements... Is there an easy way of buildin simple lo-fi ribbon? simple lo-fi Moving-coil?

Does anybody know anythong about Nikola Tesla's or Alexander Graham Bell's fist ideas as speaker elements? I Know they are fron 19th centyry so they can't be that complicated?

[Stocker]

Well, that last statement is a bit of a leap indeed!

anyhow. One member here has put a bit of aluminium foil over a strong magnet and fed it output from his amp, and it moved to the music. That would probably be simplest

[redunzelizer]

Originally posted by Mursu
I am intrested in building speaker element for my lo-fi experiments.
[...]
I am intrested in diffirent type of elements... Is there an easy way of buildin simple lo-fi ribbon? simple lo-fi Moving-coil?

One of the simplest ways to get a real "kitchenoid" speaker is the ever so (in)famous "Tin Can Driver". Grab a bigger (already opened and empty) tin can, approx 2-3 inches in diameter. Get a large inductor of a couple of mH, and a power-resistor of ~4 ohms. Wire the coil & res. in series and connect to your amp. (nominal impedance then 4 ohms, very HiFi conforming...)

Place the coil right near the bottom of the can, leaving only a small space of ~1mm so these just don't touch. Turn on the music...

A variation of the above would implement drilling a small hole into the middle of the can bottom, mounting a lengthy steel screw through that hole and placing the coil centered "around" that screw...

(The more scientifically interested readers may now speculate about resulting K2...)

There is a high end variation of this, implementing a 12V toy train transformer, a diode, two capacitors (one too small, the other of unknown value), a few resistors and one 2N3055 on an aluminum plate, with the coil as collector load of the 3055 at approx 0.5 Amps , thus giving you: pure class A tin-cannage! But never use any bridge rectifier, just one diode, else you will be accused of severe overkill! I successfully did that once as a kid, your mileage will vary though...


It should also be noticed that there are significant differences in sound quality, depending on the initial stuff that tin can contained. Some examples:
- Oil can: greasy mids
- Peaches: smooth treble
- Beans: farty bass

regards & have fun!

[infinia]

Got an old Hard Disk Drive you can take apart?
How about hooking up an amp to a HDD seek arm coil? should work and may be very interesting for speech sounds.

The mechanism that moves the arms on a hard disk has to be incredibly fast and precise. It can be constructed using a high-speed linear motor.
Many HD drives use a "voice coil" approach -- the same technique used to move the cone of a speaker on your stereo is used to move the arm.

[dnsey]

The simplest I can think of is a magnetostrictor.
Just a fairly loosely-wound coil, which will 'tighten' slightly as current passes through it.
Slightly more sophisticated versions are used for underwater sound propagation, etc.

[infinia]

I assume you are mostly after different sound effects for speech right?
Old telephone microphones driven in reverse by small BW limited amps sound pretty cool.

[PauSim]

Not a speaker project, but very lo-fi:
For a funny vocoder effect you can speak very closely in front of a house cooling fan (in Finland hmm...). To record just speak against the wind direction and place the microphone in the opposite side. Sing in a monochordic tone something like "Autobahnnnnnnnnnn" or "By your command". Changing the speed of the fan will change the modulating tone, too.

Hope this helps.

[angsuman]

This brings me back. When i was 11 or 12 I was learning about loudspeakers, and I learned about this ribbon. I wondered how this thing worked? So what i did was take a wrigley's gum wrapper rip off the paper after soaking in hot water. then take the most powerful two magnets you can get ahold of or even just one. Then place the ribbon near these magnets but make sure your amp is at low volume. The sound is surprisingly clear. Definately enough for voice intelliigabilty and will probably be your most sucessful expermient. You can then experiement with magnet positions, folding the diaphram in a V shape etc. To increase the resistence of the ribbon take a long coil of wire 30gauge or smaller and put it in series with the ribbon. You'll probably need to do this to prevent your amp from self reseting itself. Or you can use a 4 or 8 ohm dummy load resister with the ribbon your testing.
Good luck.

[tade]

http://www4.ncsu.edu/~tkwolick/ribbondeath.wmv

haha, my poor amp...

[CBS240]

perhaps you could make a small stationary coil, mounted to a base of some sort, get one of those small powerful earth magnets, attach it to a spacer(rod of equal diameter to extend a half inch or so out of the coil), connected to a paper plate that is cut to shape of cone for rigidity. Play music in the coil and hold the magnet inside it. I guess this would be like a reversed speaker, eh?