If you are having audio issues while playing Brainzy, please ensure that your device is not set to vibrate. If you have an iOS device (phone/ iPad) and your device has a physical mute switch, please make sure that it is toggled off. If your device does not have a physical mute switch (some iPads), you can tap the Silent Mode icon to turn the function on or off. If you have an Android device please check to see if the device is silent.