I'm only thinking of adding a car amp and 15-18" woofer. My mixing desk has separate outputs for subs and I assumed I should be able to get a better bass sound out of a car system as the resistance is higher. Also note that my PA is only 2 x 300w RMS speakers - not a massive system.
PA speakers aren't so expensive, its the amps that run them that costs you the big coin. I also just want to experiment. Just wanted to get some technical advice before spending any money... Thanks for your suggestions.