Jumper A and B control the bass frequency range. Jumper A sets the lower limit, while Jumper B sets the upper limit of the bass range. Excessive bass can cause speaker distortion. To reduce distortion, remove the jumper cap from Jumper A to limit ultra-low bass frequencies. Removing the cap from Jumper B increases bass output; with the cap installed, bass is reduced. Jumper C and D control the treble frequency range. With both caps installed, treble output is at maximum. With only Jumper C capped, treble is reduced. With only Jumper D capped, treble is further reduced. With both caps removed, treble output is disabled. Use the splitter board as follows: Connect according to the labeled terminals (Treble, Low, Input), connect to your speaker, ensure proper enclosure sealing, then play audio while adjusting jumpers for optimal sound. Typically, Jumper A is used while Jumper B remains unused. For treble adjustment, test different combinations of Jumpers C and D to achieve desired tonal balance. Common configurations: - A + D: Enhanced bass response - A + C: Balanced treble and bass - A + C + D: Balanced treble and bass, with slight treble emphasis - A + B + C + D: Emphasis on midrange frequencies If bass output is excessive, remove the cap from Jumper A. Adjust until preferred sound is achieved, then secure the board in place. Specifications: Model: YLY-2088 Power Handling: Up to 400W Impedance Range: 4–16 ohms Frequency Response: Adjustable Color: As shown Material: ABS plastic Dimensions: 7 × 5 × 2.5 cm Package Includes: 2 × Speaker Frequency Divider Boards Note: Color may vary slightly due to lighting and screen settings. Dimensional tolerance: ±1–3 cm.