You can change how loud the bass is on the JBL Xtreme, by turning on and off its bass boost mode. When switched on, this mode makes the passive bass radiators on the left and right edges of the speaker vibrate much more. Plus, this adds a low rumble quality to the playing program, that travels pretty far from the speaker. So, for you boom lovers, this post shows how to bass boost this speaker, to get that extra umph.
How to Turn Off Bass Boost on the JBL Xtreme
By default, this speaker has bass boost mode turned ON after a reset. This adds a bit of treble and lots of extra bass to the audio output as compared to when this mode is OFF.
You can turn this extra bass mode off by pressing and holding in the Volume Down (-) and Bluetooth buttons as pointed out by the green arrows in the last picture, for about ten seconds, until the Power and Connect buttons light up white. See these lamps circled in the next picture.
How to Turn On Bass Boost on the JBL Xtreme
To enable bass boost once more, press and hold the Volume Down and Bluetooth buttons in until the Power and Connect buttons light white. Then release the buttons. When the buttons inside the circled oval above light white, bass boost has resumed once again.
Warning
The drivers really thump when you switch ON bass boost. So take care in how loudly you play this speaker with the bass boosted, to avoid damage to the speaker drivers. If the bass is crackling, tapping, or otherwise distorting, turn it down !