i realize a 4inch speaker isnt capable of playing bass very well and distorts when bass is put through it at high volumes. to fix that problem i would like to get some bass blockers for them, however i dont know what frequencyies to block out. ive seen blockers that block that go from 0-300Hz, all the way through 0-5.6kHz. what frequencies do you think i need to block? the speaker is a kicker DS series 4in