ForeFlight Mobile offers audible alerts as follows:
500' AGL Alerts - The 500’ AGL alert is a simple callout that triggers when you descend through 500’ AGL after having been above 1,000’ AGL. The alert will only sound once every 60 seconds, and is automatically disabled if your groundspeed is less than 40 knots.
Cabin Pressure Altitude - When your aircraft cabin pressure altitude passes 12,000’ MSL and 25,000’ MSL . (Requires iPad/iPhone or external device equipped with a barometric sensor)
Runways - When nearing or entering a runway.
Sink Rate - Above 2,500’ AGL (or when AGL is not known), the alert is triggered if your descent rate exceeds -4,000‘ per minute. At 2,500’ AGL, the alert is triggered if your descent rate exceeds -3,000’ per minute. Between 2,500’ AGL and 500’ AGL the descent rate required to trigger the alert decreases linearly along with altitude, down to a threshold of -1,500’ per minute. At 500’ AGL the alert is triggered if your descent rate exceeds -1,500’ per minute.
Traffic - When traffic is within 1NM and +/- 1,200’ GPS altitude of your aircraft’s position while connected to a Stratus ADS-B receiver, a FreeFlight System, or a Flight Stream 210 AND your aircraft is equipped with ADS-B Out. Ownship must be able to be detected to work.
TFR Alerts - Audio alerts will warn you if your present track will take you inside (or over/under) a known TFR within the next 5 minutes, even if you don’t have the TFR map layer turned on. Four different alerts are possible based on your position relative to the TFR: “TFR Ahead”, “TFR Below”, “TFR Above”, and “Inside TFR”.
Destination WX Frequency Alerts - The destination weather frequency callout provides you with your destination airport’s weather frequency (whether ATIS, AWOS, or ASOS) as you near the airport.
For Weight & Balance - You will get differing audible tones when a change is made to your weight & balance and your CG falls within or outside of the CG limits.
You can trigger a sample audio alert by tapping on MORE > SETTINGS and then toggle "Speak All Alerts" OFF and back ON. When the alert is playing you can press the Volume Up or Volume Down toggle on the side of the iPad or iPhone to adjust the volume of the alert.