And if the user does nothing, then the recordings are constantly deleted after the five-minute mark.
The app also syncs with social networks so audio clips can be easily uploaded onto facebook, or emailed to pals.
It can run constantly whenever the smartphone is turned on, but it does have a red banner at the top of the phone screen to remind the user it is still on.
Heard is available free with 12 seconds' recording time, or for $1.99 for up to 5 minutes in the Apple store.