We currently know of no way to adjust the Extra Bass mode on the JBL Clip 1. But if this were possible, it would makes the speaker vibrate a lot more. So it would add a hefty bass quality to the content playing. However if they ever add this feature, it might work something like as follows…
JBL Clip 1 Extra Bass Mode: Explained
Firstly, by default, the Clip 1 would have this mode ON, as some other JBL speakers do. Indeed this mode would add a bit of extra treble and lots of extra bass bass. So it would be like switching on the Loudness control on older stereo systems.
How to Turn OFF – Proposal
Find the Bluetooth button on the speaker left side, and the Volume Down button on the right side.
You could turn this Extra Bass mode OFF by pressing and holding in the Volume Down (-) and Bluetooth buttons. Hold for about ten seconds, until the pilot lamp on the top blinks a few times.
How to Turn ON – Proposal
Finally to turn this mode back on, again, you would press the Volume Down and Bluetooth buttons. Hold them in until the light on the top flashes a few times. You would release the buttons.
Then, after a short pause, when the status light would go back a solid glow. Afterwards, extra bass mode would be ON once more.
Now perhaps they didn’t build this feature into the Clip 1 due to the very small size of its battery. Not to mention the small speaker inside. Too much bass would tend to run the battery dead much faster. Furthermore, one might damage the little driver with excess bass. So, we don’t get that feature in this particular speaker.