Currently we know of no way to switch on JBL Clip 4 low frequency mode (LFM). But if this were possible, it would make the speaker vibrate much more. Plus it would add a louder bass quality to the audio. Thus if they ever added this, it could work something like the following…
JBL Clip 4 Low Frequency Mode: Proposal
First of all, by default, the Clip 4 would have this mode ON. This is like many of the other speakers in the JBL line. This mode would add more treble and lots more lows to the audio output. It’s like switching on the Loudness control on vintage stereo systems.
How to Turn OFF — Proposal
For example, find the Bluetooth and Volume Down buttons on the top of the speaker. So find these circled in the picture above.
Then, you could turn low frequency mode OFF by pressing the Volume Down (-) and Bluetooth buttons. Hold them in until the pilot lamp blinks a few times, as we show in the next picture.
Finally, to turn low frequency mode back on, again, you would press the Volume Down and Bluetooth buttons. Then, hold them in until the light again flashes a few times. You would release the buttons after that.
However, as it turns out, there appears to be no such mode on this speaker. Perhaps the designers figured that it would cost too much in terms of battery life. After all, this speaker does indeed have a rather small battery to enhance its portability.