Originally Posted by RonRizz

Not true at all. Remember, eq's are best used to cut frequencies, not boost. Any listening environment will have its own inherent Imprint on sound, and your eq is made to tailor that sound for that reason.
One example is... Most hatchback cars seem to accentuate at or around 80hz tones. Simple Bass and treble controls work mainly on 100hz, and 1000hz, respectively, with a pretty wide "Q". In other words, if you turn down the bass, you are in effect turning it down at 63, 80, 100, and 125hz at the same time, albeit in different levels. Your eq will let you decrease precisely at 80hz, without affecting 63, 100, ect, ect.
A great sound system can sound fantastic without an eq, but the addition of one makes things muy beuno.