Why playing via AUX cut's on quiet passages in the songs/movies?

As a workaround, you can run a signal generator app in the background, set to very low frequency like 20 Hz, and low but not too low amplitude. Flip4 will reject this frequency and not distort/waste power, but it will be alive all the time.

"Hi, I’ve found that going into the so-called “low frequency mode” fixes it completely - after also having made a firmware update (so my firmware is now as of 1-aug-2020).

For those unaware, “low frequency mode” does not put in a low frequency booster, as it might sound, but instead disables the sound processor. The same sound processor that cuts out quiet sounds also cuts low frequencies at high amplitudes, to avoid distortion - therefore they call this disabling “low frequency mode” because there will be no more low frequency CUTTING. So, thank you JBL, but I like my sound just as it is; if it’s so loud that it distorts, I can take care to lower the volume or put in an equalizer as I desire.

So:

longpress bluetooth + volume minus - go into “low frequency mode” a k a unaltered sound; longpress them again to return to “processed mode”

Restarting or shutting down reverts to the default “processed mode”."

"It is possible to hack the pcb to fix it. Extract the board, locate Q12, and solder a wire that shorts its collector (middle terminal) to ground. This will make Flip 4 think there is always audio going into aux.

You may also want to remove 33-ohm resistors, that may reduce distortion for signal sources that have high-ish output impedance.

This hack causes a few side effects though: Bluetooth pairing sounds will not be played. Bluetooth audio does work, just no pairing sounds."

"I don’t have a fix fix, but I have found that I can turn on a YouTube vid of a constant 12hr dog whistle and that will keep the speaker awake.

There is still sound coming through the speaker, but you can’t hear it, so it doesn’t interfere with whatever you are listening to.

Might annoy ya dog though. But I turn YT’s volume down really low and that still keeps it awake.

You would think in the 2 year span from the original post that JBL would have figured it tf out."

What I did to get around this was plug it into power, BUT, when I tried to fix this issue while plugged in with an iPhone charger(the dinky 5w one that comes in the boxes of most iPhones), it did NOT work. I used a more powerful wall adapter and there is no more cutting out. Hope this solves your issue:)