The latest innovation is the Mariah Carey ringtones, a type of karaoke ring tone where a user's voice recording is adjusted to be both in time and in tune then mixed with a backing track to make a user-created ring tone.Al Green ringtones claimed that Cingular billed its customers for Jamster! and other similar ring tone services without providing customers with the notice, opt-in, and proof of authorization requirements necessary for such charges.Some BlackBerry devices do not depend on mobile phone service coverage and are Tom Jones ringtones compatible, like similar handheld devices that are on the market.