How to adjust the bass and treble of CXA1005

CXA1005 is a dual-front Walkman integrated circuit with power amplifier. Only one 100kΩ potentiometer is used to adjust the volume of the two channels. So a CXA1005 circuit was assembled for listening. The high and mid-range sounds were very strong, but the bass was not enough. So a 10kΩ potentiometer was used to connect the 6.8kΩ resistor at pin ① and the 6.8kΩ resistor at pin ⑧ in parallel for adjustment. When the bass was strong and clear, the resistance was measured to be around 3.6kΩ. The two 6.8kΩ resistors were replaced with 3.6kΩ (or the 6.8kΩ resistors were replaced with 10kΩ adjustable resistors, so that the high and low frequencies can be adjusted at any time), and the sound was much better.