This jumper cap kit lets you tailor bass and highs on compatible speakers. Use A, B, C and D to shape your sound and reduce distortion on deep bass without changing the speaker electronics. - Jumpers A and B control the bass range - A sets the lower limit of the bass range. Removing the cap from Jumper A limits super-deep bass and reduces distortion. - B sets the upper limit of the bass range. Removing the cap from Jumper B increases bass; with the cap on, bass is reduced. - Jumpers C and D control the height range - When the caps on Jumper C and Jumper D are on, the highs are the loudest. - Important consideration - On some speakers, the bass can distort if it is increased too much. Use scenarios - You hear muddiness or distortion with heavy bass on certain tracks. Remove A cap to limit deep bass and reduce distortion, while adjusting B as needed. - Your speaker undersells bass punch. Remove B cap to increase bass response, then fine-tune with A as the lower limit. - You want brighter, crisper highs for cymbals or treble-rich recordings. Put caps on C and D to maximize high-frequency output. This setup provides adjustable bass and treble control without altering the core speaker circuitry, helping you achieve clearer sound and better balance across music and movies.