On iOS you can not change the Lock Sound or the Volume Sound. This is annoying for people who like to personalize every aspect of their iOS device and even want their favorite sound to play every time they lock their device or change its volume using the side buttons. The new CustomSounds tweak makes it possible for users to customize this aspect of their device, by allowing them to choose a different sound for when they lock their device or change its volume.
After installing the tweak you can change the sounds by opening the tweak’s Settings page. There you will see two separate options for Lock Sound and Volume Sound. Tap on the one you want to change and the from the next screen choose the sound you want. Now the tweak offers a few options for Lock Sound including Default, Nintendo and Organ. For Volume Sound only OS X sound is available right now.
The CustomSounds tweak, which brings a fun feature to iOS and is still in beta will become more useful and fun when developer adds new sound effects and perhaps add other customization options than the two available right now. You can download the CustomSounds tweak’s beta from Cydia by adding ‘https://repo.d4ni.nl/‘ to your Cydia sources.