1. Control Range: The 7-band equalizer circuit's control range is ±12dB, with equalizer bands at 60Hz, 150Hz, 400Hz, 1KHz, 3KHz, 6.5KHz, 15KHz, composed of original TL074 chips from TI or ST. 2. Basic Parameters: The 7-band audio equalizer features a pre-gain boost; the 4580 classic op-amp provides 5 times amplification (14dB); input impedance is 20K, and output impedance is 600 ohms. 3. Headphone Compatible: The audio equalizer's ear amplifier section is composed of NE5532, forming a Type 47 headphone drive circuit, easily driving all types of headphones with adjustable highs and lows. 4. 3.5mm Interface: The 3.5mm input interface supports a 4-pole connector. The output connects to a headset with a microphone, allowing for normal voice calls on mobile phones. Another terminal with a group of lotus interfaces is also available. 5. Aluminum Alloy: The 7-band car audio equalizer is constructed from aluminum alloy, offering high strength, corrosion resistance, and stable performance. It operates on a DC5V-12V power supply and supports dual-channel audio.