The filename or HTTP URL of the sound file played when the mouse enters the button region.
The control supports .wav files.
If the filename is an HTTP URL you can use the proprietary compressed format AMZ.
When sounds are set at design-time, you do not need to distribute the sound files with your application. This is because they will be included in your program at compile-time. Redistribution of sound files is only necessary when the button's sounds will be changing at run-time: see the How to change button resources section for further details about setting sounds at Design-time.