A mp3 player can use a car amplifier. LF 353 is changing audio signal to 3 bands.
Three Band Active Tone Control Circuit
Low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage They require low supply current yet maintain a large gain band width product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents.