i have a home cinema powered subwoofer which had a transformer 240v/12v and the wires to the transformer were 2 blue and 1 black as shown in picture and need to know how would i wire in a 12v power supply. i want to put this in my car as its 200w to run my 6x9 speakers. many thanks in advance and feel free to reply

 

You can't really.
That is a center tapped winding and it will give + and - "12V" (actually +/- 16V or so) for the amplifier.
Also, it will only be 200W in the advertising department's eyes.
You will do better to buy one designed to run in a car.
But 200W in a car is really quite dangerous, as well as I think quite annoying to those poor people who have to put up with the Duuff Duuff supposed mating call.

 

Deleted double post.

 

Yes, the 12V in a car cannot produce the needed +16V and -16V that the amplifier needs. An ordinary modern bridged car amplifier produces 200 Whats or 15 real Watts into each 4 ohms speaker.
Also, your subwoofer amplifier might have filters for it to produce deep low frequencies that 6 x 9 speakers cannot play.