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I need to get audio from my computer's headphone jack and push the output to 2 sets of speakers. I have tried using a cheap splitter from Fry's, but one set of speakers ends up acting as a microphone (!?) for the other set of speakers.

What's the best way to split headphone output and get best quality with no interference on each set of speakers?

I would, of course, also be interested in why the cheap splitter causes one set of speakers to start acting as a microphone.

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When you say 'acting like a microphone,' do you mean you can talk into one set of speakers and hear your voice coming out of the other? (If so -- impressive!) Or does your computer see the other set of speakers as a microphone? – Joshua Dec 18 '09 at 21:15
I mean I can talk into one set of speakers (in this case, Sony headphones) and you can CLEARLY hear me in the other set!! – Jeremy White Dec 19 '09 at 5:22

Speakers and microphones are mechanically very similar.

Microphones work by using vibrations in the air to move a magnet, which sits inside a coil of wire. Current is induced in the wire, and interpreted by the computer as sound data.

Speakers use the same process in reverse; sound data is converted to electrical current, which runs through a coil of wire around a magnet. This causes the magnet to oscillate, vibrating a membrane.

(You can plug a cheap microphone into your sound-out port, hold it up to your ear, and hear this in action).


I imagine the cheap splitter just connects the 3 connections together (the male input and the two female outputs). The speakers are then inputs to each other; from their perspective they can't tell if signal is from the other speaker or from the computer.

I naively imagine a better quality splitter would use magix to prevent this. You are still likely to get degraded sound quality, or at least a decrease in volume.

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Are there powered amplifier/splitters out there that I could purchase? I'm not finding any on Amazon or Frys. – Jeremy White Dec 31 '09 at 2:43

Get a slightly less cheap splitter from Fry's? I have a few of them that I use for this purpose and I've never had problems with interference. And I tend to get the cheapest one I can find. I think yours is just broken.

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up vote 0 down vote accepted

This set of speakers from Altec Lansing works beautifully!

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