Speaker Re-Wire

[KurtIngamells]

I am trying to get an old speaker to work. The wires going onto the speaker magnets themselves are the original wires and they've remained attached perfectly the whole time, so the problem is between the wire and the audio jack. I connected the positive and negative wires to an audio jack which I cut open and stripped the wires of, but there is 3 wires in the jack (red black and green) and only 2 black wires for the speaker. The speaker plays music from my laptop using the audio jack perfectly, but it's really quiet. The speaker doesn't require a power source to boost / amplify the sound, so I don't know what the problem is. Any help would be great. Pictures should be attached.

 

[Jagtech]

The audio out on your laptop is stereo, hence the three wires (left, right and common). I don't think the laptop output is going to have enough amplification to drive that speaker.

 

[KrisBlueNZ]

Hello and welcome to Electronics Point.

First, yes, the speaker will be very quiet. That's because the laptop's audio output is only designed to drive headphones. You DO need an amplifier if you want to get good volume from a speaker with a headphone-level signal.

Second, the jack plug has three wires because it's stereo, like the headphone output of the laptop. The wires are 1. left channel signal, 2. right channel signal, and 3. common. The left channel signal appears between 1 and 3, and the right channel signal appears between 2 and 3. You can figure out which wire is which if you have a multimeter. The three metal contact areas on the plug in your second picture, from left to right, are called the tip, the ring, and the sleeve, and they correspond to 1, 2 and 3 in the description above.

What you hear in the speaker depends on which points you connect it to. If you connect it to 1 and 3, you'll hear the left channel audio. If you connect it to 2 and 3, you'll hear the right channel audio. If you connect it to 1 and 2, you'll hear only the DIFFERENCE between the left and right channels. With most audio sources, this gives a weak, hollow sound, with very little bass and vocals. So don't do that!

But no matter how you connect it, you won't get much sound out of it without an amplifier.