I am getting a harmon kardon reciever for christmas and i plan to either get some entry level klipshe speakers or make my own like on speakerbuilder.net. it is mainly for a small room but might be used in a big room. what do you recommend? also, i plan to get an adire shiva and tune it to 20 hz, powered by a 250 watt plate amp. what airspace should i use?