capacitor question

is anyone using a capacitor with their tower speakers? i am thinkin about putting one on mine when i do a speaker install in the next few weeks, everyone i know that does car audio tells me i need one, what are yalls thoughts on the matter? i mostly just hear bout using them with subs in the boat, my sub doesnt cut in and out but im wondering if it will once i have the speakers running off the same battery. also this is all goin in an 86 2001 and there is only room for one battery so we cant add to that, hope yall can help