If you want to tweak your headphones’ sound, it usually means cracking it open and voiding the warranty. Unless you are using the Sleek Audio SA6, that is. The Sleek Audio SA6 are modular noise-isolating earbuds that comes with six pairs of interchangeable filters, called ports, that can be used to reduce or increase the treble and bass. The reviewer noted that swapping ports is quite easy, and so is losing the small parts of the earbuds. It also offers double-flanged silicone eartips that blocked out surrounding noise effectively. Using the “plus” modules for both the bass and treble produced accurate and pleasant sounds. Bass was great but not overwhelming though highs seem to have a lesser kick. For those who feel that a digital equalizer is not enough, pairing one with the Sleek Audio SA6 will let you enjoy an almost limitless sound tweaking.