OMrun will give you audio feedback on your selected metrics every 1km (or 0.5 miles). In case you can't hear the audio cues follow these steps to make sure you're properly setup:
1. Make sure you enable the Audio Feedback feature before you start your run.
2. Turn up the MEDIA volume on your iPhone.
Note: Pressing the Volume UP button on your iPhone while OMrun is running will only turn up your ringer volume unless you do it exactly when the voice is speaking.