DAF Jammer is a free app that can be used to experiment with the phenomenon of delayed auditory feedback (DAF). The app allows you to control the amount of delay and the volume of the audio feedback.

When you first open the app, you will be presented with a setup screen, which will allow you to choose the audio source (microphone or headset), the subject (you or a person), and the amount of delay (from zero to 500 milliseconds).

If you select the microphone, you will be able to record the subject's voice and then play it back to yourself. You will also be able to change the volume of the audio feedback.

DAF Jammer is currently targeted for Android devices with built-in echo cancellation capabilities.