You can adjust the bass response of the JBL Charge 4, by turning on and off its low frequency mode. Thus, when ON, this mode makes the passive bass radiators vibrate a lot more. Further, low frequency mode adds a decidedly “thumpy” quality to the content playing. This makes this speaker sound much bigger than it actually is.
JBL Charge 4 Low Frequency Mode: How to Toggle OFF and ON
First off, by default, this BT speaker has its bass mode turned on. Furthermore, this adds a bit of extra treble and lots of extra bass to the audio output.
You can turn this low frequency mode OFF by pressing the Volume Down (-) and Bluetooth buttons for about ten seconds. Plus, you keep holding them until the oval ring around the buttons lights up. E.g. Find these buttons on the top of the speaker, as we show above.
Also, to turn low frequency mode back on, again, press the Volume Down and Bluetooth buttons. Hold them in until the oval button ring lights up again. Then release them. Finally, when the ring goes dark, low frequency mode is active once again.