IOS – What are the default sounds for iOS 7

It's a security feature.

iPhones don't connect to routers that have factory default SSIDs, such as default, linksys, dlink, etc... This protects from the following: as you traverse the world, you will certainly pass by locations that are not customized and therefore have a default SSID with no password. Your iPhone would connect to these networks without you knowing. This is fine and all, unless someone is fishing for people to connect to their network so that they can read the traffic.

Ultimately, connecting to an unknown network is risky.

An even better Idea is to got to ~/Library/Sounds and create a sound file with the same name as Basso.aiff and it will supersede Basso without the need for deleting a system sound file.