You did not identify the model of the computer, nor the type, style of speakers, but there are some generic things to consider.
The beige series of computer used 1/8 inch mini stero jacks, so any speaker set would need a matching plug. Most computer speakers are =stero= and have a device with jacks to connect the two speakers as well as a =pigtail= to connect to the computer, the pigtail having a 1/8 inch mini stero plug. Sometimes the speaker connecting device has an extra jack so a sub-woffer can be included in the setup.
Most setups of this sort require some power and one of the speakers has a power jack so a power supply transformer (wall wart, a.c.adapter) can be connected.
Does this sound like your setup?
Since 2000 with the introduction of the first iMac series the speaker jack at the computer is a sub miniature stero jack. All Macintosh since then has the sub miniature jack, but otherwise the same interconnections are made.
Does this sound like your set up?
regarding the =three= wires of your speaker, do they have any color coding on the plug ends?. OH! by the way where did you get the speakers, if new do they have an instruction manual? If used, do you know who owned them before and can you reach that person and confirm that the speakers once connected to a computer succssfully?
And probably the best advice to help you find the answer, take the speakers to Radio Shack and tell them you need help connecting to your computer. Of course tell them what size the speaker jack is on the computer. They have adapters if it needs to go down or up in size/
At this point you do not need to tell them it is for a Macintosh because they will fixate on that and ignore your connection issue.
hth
