The interior gear also allows for a full range of EQ controls. From the Marshall app on your phone, you can make a number of adjustments to find the sound you wish. To the speaker itself, You need to use the brass control panel to adjust bass and treble. https://www.bluetoothspeaker.top/bluetooth-speaker-column-stereo-hifi-heavy-bass-wireless-soundbar-subwoof-loudspeaker/