OK so an Arcade machine obviously needs a sound system. Many people seem to like hacking a set of PC speakers either for the amplifier, the drivers, or both. Well I'm afraid that just won't cut it for me, as you never know what the quality will be like. I also collect Pinball machines, and they use a 5" driver for the bass, which works very well. So I bought a couple of these from Maplin. I also had a pair of 4" Kenwood car speakers spare so they are used for the speakers under the marquee. For one of my other projects I used 4 channel car amplifiers which work great, and as I had a spare I decided to use that. I'm only using 2 channels, so if you're buying a new amplifier a 2 channel one will be fine. The 2 speakers on each channel are connected in parallel - car amplifiers are designed to drive speakers with a very low impedence so this is not a problem (which it may be with a conventional amplifier).

One issue I have found since installing these is that the lack of magnetic shielding causes coloured blobs to appear on the monitor screen after a while - oops.

	The 5" drivers from Maplin.
	The 4" drivers from Halfords.
	The amp I used is one of these, that I also use in my Whole House Audio system. SPL do a 2 channel version that's in the same footprint.
	I used these crimps to wire in the speakers to the amp. The top connectors screw to the terminals on the amp, and the bottom connectors are at the speaker end and push onto the terminals.
	A view of the wiring to the bottom speakers. The wires are routed using P-clips from Maplin.
	The wiring to the amplifier. The line level and power leads are not yet permanetly routed as I havn't decided where the PC and amp power supply will go.
	Wiring from the amp goes up the back of the cabinet to the top speakers.
	Top left speaker with wiring in place.

I temporarily used the 12V power from the computer internal PSU to drive the amplifier. Although this does work, unfortunately there is a lot of electrical noise on that 12V rail which means that when the volume is cranked up you can hear wierd noises through the speakers such as when the computers is accessing the disk or other things. To avoid this I bought a plug-in 12V switch mode PSU from Maplin. It's rated at 1.2A which is sufficient to power the amp even at high volumes and has eliminated the strange noises!