Jumper based audio tuning kit using Jumper A, B, C, and D to shape frequency response and reduce distortion. Designed for compatibility with speaker systems that support jumper adjustments. Key benefits - Distortion reduction at the low end: connect Jumper A cap to limit very low frequencies and smooth the sound. - Further reduction when B is on: increasing Jumper B cap while B is ON helps reduce distortion. - Treble shaping: Jumper C and Jumper D control the treble range; using both gives the strongest treble presence, with finer control possible by engaging only one. - Range control: Jumper A defines the lower bound and Jumper B defines the upper bound of the audio range; a larger range can cause distortion on some speakers, so adjust carefully. Compatibility and usage notes - Intended for compatible audio devices that use this jumper-based tuning method. - Specific size and material details are not provided in the original specification. Use scenarios - Scenario 1: Tuning a compact bookshelf speaker to reduce low-end distortion while preserving a clear high end. - Scenario 2: Dampening harsh treble on a bright speaker by adjusting C and D to balance the treble range without compromising overall loudness. - Scenario 3: Calibrating the overall audio range in a system to prevent distortion from excessive upper-bound control, especially with compatible speakers. This description preserves the original functions of Jumper A, B, C, and D while presenting clear, customer-friendly guidance for practical use.