I'm about to lose my mind. I'm running the default twitter app and when I get a mention my phone chimes. That doesn't sound bad, right? Here's the problem...
It chimes a sound, chimes a second separate sound, and then another sound that is the sound of my phone ringing!
I'm not making this up. I have looked at my profile settings over and over and have mentions set to ring a simple tone!!!
Ok, your Twitter settings may be set to send a copy of your messages/mentions/replies to your inbox so you may be getting Twitter notification sounds from the app itself, then maybe another sound from your inbox, then if you are using BeBuzz you may have the settings set up to play sounds from BeBuzz as well. If you do have BeBuzz set the sounds from active to silent. Let me know if this helps any, also I am sure you are running OS 7.1 but let us know so we can help more.
