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. On some speakers, excessive bass can cause 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 maximum. With only the cap on Jumper C installed, treble is reduced. With only the cap on Jumper D installed, 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 response.Common configurations include: - A + D: Enhanced bass response - A + C: Balanced clarity in both treble and bass - A + C + D: Clear treble and bass, with emphasis on treble - A + B + C + D: Emphasis on midrange frequencies If bass output is excessive, remove the cap from Jumper A.Once optimal sound is achieved, secure the board to your speaker unit.Power handling: Up to 400W Impedance: 4–16 ohms Frequency response: Adjustable Color: Red Material: PC + metal Package includes: 1 × Frequency Divider Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 cm.