Rap songs don't go as long as most people think whereas I have heard certain classical material go as low as 9 to 15 Hz. Try reproducing that with your port tuned @ 30 Hz.
no i dont think you get it, running a recording through a processor, an amp, then speakers can change it, especially with room acoustics and box tuning. Ever seen a recording studio? Wonder why they have 10 thousand dollar monitor speakers?