Jumper set with four jumpers A, B, C and D to adjust bass and treble ranges. A and B control the bass: A defines the lower boundary, B the upper boundary of the bass range. C and D control the treble: when the caps on C and D are installed, the highs are the loudest. Benefits and how it helps - Precise tone control: tailor bass and treble to your speaker and listening preference with simple jumper caps. - Distortion management: if you experience distortion from deep bass, remove the cap on Jumper A to limit super-deep bass and reduce distortion. - Flexible bass shaping: removing the cap on Jumper B increases the upper bass limit; keeping Jumper B capped reduces it. - Treble customization: with Jumper C and D, you can maximize highs when desired. 2-3 practical use scenarios - Distortion-prone speakers at high volume: remove A cap to limit deep bass and reduce distortion while preserving overall depth. - Genre-specific bass tuning: adjust B cap state to widen or tighten the upper bass range to suit rock, pop, or electronic music. - Highs-focused listening: install caps on C and D to achieve the loudest treble for detailed cymbal and vocal clarity in acoustic or cinematic content.