just change the head unit to something better and u'll get nice treble and bass combination..
most important is the player u're using, after that is speakers..

A tweeter is a loudspeaker that reproduces only higher audio frequencies. Because it is limited to high frequencies, a tweeter must be combined with speakers that reproduce other frequencies in order for the full range of recorded audio to be audible. The average tweeter outputs frequencies from approximately 2,000 hertz (Hz) and above. 20,000 Hz is considered to be the upper limit of human hearing, but some tweeters can produce frequencies even higher.

A full-range stereo or home theater system uses at least one other speaker in conjunction with each tweeter to produce a full range of sound. In a 2-way speaker, the high frequencies, also called treble, produced by the tweeter are paired with a speaker known as a woofer that reproduces low end or bass frequencies. More complex speakers use other drivers in addition to the woofer and tweeter to reproduce midrange frequencies. In home stereo speakers, the tweeter and other drivers usually share a common enclosure. In some car stereo systems, however, each component may have separate housing to provide additional flexibility in directing the sound.