Now for this set up the two speakers and sub, What cable would I need to hook the speakers up to the Amp and also the Sub to the speakers/amp and then entire thing from the Amp I believe to the computer?
Regular speaker cable to connect the speakers to the amp. Speaker cable can be as cheap as you like, or as expensive as you like. There are as many brands available, as there are opinions on what speaker cable you should buy.
I think anything up to say £2pm is fine. Personally, I don't see the point in paying much more for budget speakers around the £100 mark. As long as the cable is oxygen free, then that is the more important than whether it costs £1pm or £20pm.
You can buy some decent OFC (oxygen free cable), clear sheathed from the famous auction site, about 10m for £5. It's good stuff, and it's cheap. Currently I'm using Van Damme Concert Grade 2x2.5mm. It's 4x the cost of the clear sheathed cable, and I can't say it sounds any different. It is nicely made cable though, and being black, for me it's easier to hide.
If one is spending up to £1k on speakers, then the more expensive cables may play a bigger part in getting better sound from the speakers.
As for the connection to the sub. A lot of subwoofers have both speaker level and low level, or sub inputs. A lot of the budget amps, do not have pre out or dedicated subwoofer connections, so you would have to use the speaker level connection to the subwoofer. The QA subwoofer has both types of connection according to SuperFi, so there should be no trouble connecting to the majority of amps.
For connecting the amp to the PC, you would use a stereo RCA to 3.5mm male cable. Doesn't have to be expensive, just something well made. Depending on what length you would need, around £5 or so, will get a decent cable.
Now the AMP? Would I just need a base model amp or would buying a better quality with more capablitys improve sound quality? And also how would I set up the Amp to give the speakers/sub the correct wattages and so on? Really have no knowledge in this department.
The more money you spend on amp, the better sound quality you will get. A £300 amp will sound better than a £150 amp. If you buy a second hand amp, you can get more for your money. Obviously, you get no warranty though. Some people like the peace of mind a warranty brings with a new amp.
Well made amps are pretty reliable though. Buying a used TV is far more risky, as many things can go wrong. A good solid amp that has been cared for by the previous owner, should work for many many years to come.
I've got an Audiolab 8000A, which is around 15-20 years old now. I bought it about 2-3 years ago now, but it's built like a tank, and it still sounds great, despite it's age.
If you would rather buy new, then Onkyo, Cambridge Audio, Denon, Pioneer and TEAC, all have amps around the £150 mark.
You don't need to worry about the correct wattage. A lot of budget speakers have around 20w-100w power handling. Some may be slightly different. A lot of budget amps, have around 40-50w output. That is a lot more than it sounds. My 8000A is rated at 50w, I very rarely have it more than 25-30% volume. Any more would be way too loud for me.
What you do not want to do, is turn the volume up to max. Even if your ears can take that amount of volume. At near to 100% volume, the amp will clip and distort. If that is kept up for any length of time, eventually it will destroy the speakers. It's not volume that wrecks speakers, it's clipping and distortion.
Anybody would probably have to be near deaf to have a 50w rated amp turned up to 85% or more.
For all but insane people, 50w is more than enough to leave plenty of headroom, so the speakers don't get damaged.
