5.1 surround sound

Hi everyone, I'm brand new to mac-forum so forgive me if I write in the wrong forum etc.
I was wondering if there is an easy and free (or at least cheap) way to change the out-put of my imac to 5.1. surround.
I have a 27" imac 2.66 intel core i5, 4gb ddr3 and I use a Logitec X-530 which doesn't have an optical connection. I searched the forum and the net. The only way seems to be to change the speakers or get an external sound card.

Thanks

Cavez

The sound card is probably the cheapest way. You could try this:

Convert an optical audio signal to 6 discrete analog RCA audio signals SPDIF & Stereo also - 5.1 & 7.1 AUDIO SWITCHER

That's about the cheapest you're going to find a converter.

As you probably already know, your Mac is perfectly capable of outputting OPTICAL 5.1 surround, but since you don't have an optical connection I would guess Bob's right as usual.

Hi,
Thanks guys. I think for the price I'm probably better off selling my speakers and get a new set with optical output. Can anyone point me in the right direction for a proper audio setup for my mac? (Amplifier, sound card for recording also and speakers?)