I'm using the following code to start a foreground service with a notification.
While Sound is set to false, the default sound is always played along the display of the notification.
B4X:
Dim n As Notification
n.Initialize
n.Icon = "notification"
n.Sound = False
n.Vibrate = False
n.Light = False
n.OnGoingEvent = True
n.SetInfo(B4XUtils.AppName, "Running...", Main)
Service.StartForeground(1, n)