I have Samsung 5.1 surround sound speakers. They don't have a built in amp and use speaker wire. I think I could use a DVD player with speaker wire ports and give it the input from my PC. Is there anything else I could use beside a DVD player and would it have enough power. How could I wire it up? Would it be possible to add two other speakers and make it 7.1? or could I get it to run of a two channel amp?
the dvd player with speaker wire ports you refer to is likely a combination dvd player/receiver often found in home theater in a box sets. some dont have many inputs for other sources while some do. its hit or miss and hit or miss in terms of quality too. if you already have the control unit dvd player/receiver which came with those 5.1 speakers then you might be able to use it. if it is broken and doesnt work then i wouldnt replace it with the same thing i'd go with what i mention below.
what you want is an audio video receiver (avr or receiver for short). they are often about $150-200usd for cheaper models. most support 5.1 while some may support 7.1.
if you bought a 7.1 you could add extra speakers yes, if you did not then no. i'd not add more though as normal surround sound content is 5.1 and there is a lack of 7.1 content. also since the speakers will not be matched things may sound a little odd. 5.1 receivers are also cheaper
if you bought a stereo amp you would only be able to power two speakers and thats it. no 5.1.
if running a receiver there are two options... connect up to your video card via hdmi/dvi and then pass your video out the back to your monitor (works best if using a single monitor or tv) while the receiver takes the audio and sends it to the speakers or connecting up via spdif optical or coaxial. you will get better sound via hdmi (since it supports 5.1 uncompressed audio) while surround (5.1) is only supported as compressed over spdif.
Whatever you use (or buy), in order to get real 5.1 sound from these speakers (apart to connecting them to 5.1 amplifier), you also need to feed 5.1 sound off your PC. As ssddx mentioned, one way is to use HDMI from your video card. Two more options (and all these depend on whether your amplifier/receiver has required inputs):
- use SPD/IF output from your sound card (optical or coaxial), and feed it into SPD/IP input on the receiver;
- use discrete outputs (FL, FR, BL, BR, C, B) from your sound card and connect them to discrete inputs on the receiver. I haven't seen recently receivers with these inputs.
No control unit/dvd player came with the speakers. I have bought a stereo amp for the two normal speakers. I have spd/if output on my sound card. I was thinking of buying a dvd player for around £20 used and there's no way I'll spend £100. I bought the speakers for £20, would a dvd player work well then or not? would I be better of selling the speakers again?
"Normal" DVD players won't let you use them as amplifiers (I haven't seen a DVD player with "inputs"). I haven't seen "Normal" DVD players capable of connecting speakers to either. You need a receiver for full 5.1 reproduction of the 5.1 sound from your PC. And if you can find a 5.1 receiver for GBP100, consider yourself lucky.