Connect the device, adjust the frequency controller, and control the gain.

1. Connect the audio source (such as music player, mixer, etc.) to the input port of the DOD231 equalizer through the audio cable, and connect the output port of the equalizer to the speaker or recording device.

2. The DOD231 equalizer has three frequency controllers, representing the bass, midrange and treble bands respectively. Turn the corresponding frequency control to increase or decrease the volume of a specific frequency area as needed. Bass frequencies are below 100Hz, midrange frequencies are between 100Hz and 2kHz, and treble frequencies are above 2kHz.

3. There is a gain slider below each frequency controller, which can be used to control the gain (also called attenuation) of the corresponding frequency band. Pushing the slider up increases the volume of that frequency band, and pulling it down decreases the volume. Adjust the position of the gain slider appropriately according to the desired effect.