How to prevent brief audio cut-outs when using sleep aid apps

When attempting to use an app like Relaxio or Sleepo to drown out background noises when sleeping, I am frequently awoken by the sound cutting out for a fraction of a second. This occurs roughly every 30-90 minutes on average and largely defeats the purpose of using the app in this manner.

Reviews of the apps in question indicate that such problems are very rare, yet I am experiencing this issue on both a Samsung Galaxy S4 and a Samsung Galaxy S7.

What measures can I take (not excluding rooting the phone) to make these apps work properly?