We know of no way to increase the low response of the JBL Clip 3 with Extra Bass mode. But if this were possible, it would make the speaker vibrate more. Plus, you’d get a surprisingly large rumble quality to the content playing. Indeed if they ever added this feature, it might work something like as follows…
JBL Clip 3 Extra Bass Mode: OFF and ON – Proposal
We propose that by default, the Clip 3 would have this mode ON by default. This is how some of the other speakers in the JBL line work. Specifically, this mode would add a bit more treble and lots of extra bass to the audio output.
JBL Clip 3 Extra Bass Mode: How to Turn OFF, and then ON Again, Proposal
Find the Bluetooth button on the speaker right side, and the Volume Down (-) button on the upper left front.
You could turn OFF extra bass mode by pressing the Volume Down (-) and Bluetooth buttons. Then hold them in for about ten seconds. Finally release them when the pilot lamp on the top blinks a few times.
Next, to turn this mode back on, you would again press the Volume Down (-) and Bluetooth buttons. Then hold these in until the light on the top flashes a few times. You would finally release them when that happens.
Then, after a short pause, the status light would go back a solid glow. After that, extra bass mode would be ON once more.