The Physics of Loudspeakers

[Shammah46]

this is so cool anyway quantumboffin is this will take me smoothly through my practicals and experiments at UNI

[jochal71]

How would the operation differ if the coil had been wound on a metal tube or something thats made out of metal instead of plastic?

[QuantumBoffin]

@jochal71 Unfortunately the speaker would become less efficient: the alternating current in the coil would induce eddy currents in the metal which would reduce the strength of the magnetic field.

[eeeedward84]

What do you use to connect the ipod to the signal generator?

[rolingpingu]

In a music device, what will make the DC from a battery convert into AC (so the speaker can work) ?

[143memai]

ROFL!! Home made speakers.. Who need JVC or SONY :P

[rolingpingu]

Thanks to u sir, I'll pass my physics class (I needed to understand this to do a project that will save me from failure)

[mugumbo5]

I would like to recreate this but with a slight change. I want to make this same bottle speaker but have the sound be stereo which requires two speakers. How would you suggest going about this and what kind of wire are you using in your video. The wire i have is speakers wire and will not coil that well as it is much more slippery.

[QuantumBoffin]

@mugumbo5 The wire we use is a monofilament wire (speaker wire is usually made up from multiple stands): The advantage of using a single thread of wire is that it's easy to coil and can handle a large current; the disadvantage is that the metal wire (inside the plastic sleave) easily breaks, cutting your circuits.

[mugumbo5]

@QuantumBoffin Thank you for your help, Your video partially inspired me to make my own headphones. But, when they play music through them the sound is extremely quiet. Do you have any suggestions to make the sound louder?

[Mrwemed]

That shits mad. But good. Think I'll stick with my amp and Bose speakers. Better that coke speakers lol.

[MultiMuffin21]

u gotta be kiddin me!! i love physics

[Orcinus24x5]

HAH! Awesome choice of song! Message in a Bottle! :D

[evasionoO]

What changes if you:

• use a bigger magnet;

• do more coils?

Thanks, really helpful video.

[QuantumBoffin]

The speaker would become more efficient.

In my setup the wires and amplifier soon become quite hot because of the current the amplifier needs to supply to create any appreciable sound. The magnet I used was a neodynium, and hence pretty strong - the biggest factor in the efficiency of this speaker is simply the number of turns on the coil (although a better designed magnet would make a difference).

[evasionoO]

@QuantumBoffin I think I get it, thanks again!

[TruEviLuKki]

What kind of codecs does the bottle use to decode mp3s?

It doesn't seem to handling them too well, you might need an upgrade.

[marta777ful]

cool ;)))))