[spareshoota]

I have the 16gb black AT&T iPhone 4s and lately it's been making the tri-tone noise at random but shows nothing. That specific noise is only associated with the receipt of voice mails, but there are none when it makes the noise. I went into the reminder part to make sure it wasn't set and I verified that I want the phone to only make a noise once when it receives something (messages, tweets, etc). Anybody else having this problem?

[matrix2004]

That's just Siri messin with ya. LOL.

[BrindawithanI]

Just a stab in the dark, but I've noticed that since ios 5 and/or the last update that Facebook shares the tri-tone. Do you by any chance have it installed?

[Guacho]

Same thing happened to me a few days ago, i'm using ios 5 in an iPhone 4

[gthugballin]

in notifications you have the option to make the sound but not show any message.... so go to notifications and see what you have selected to not pop up... i guarantee you it has "don't show anything" selected.

[_heatherly]

Yeah, this has happened on mine and it seems go be Foursquare related. I set it not to have any pop up notifications, but when I check the Notification Center, it shows an alert.