I hear TIMEOUT but dont know who called it

[lmeadski]

Do you still not grant the TO unless you know for certain who called it? I dont have a hard time discerning a TO call from the bench vs. the crowd (primarily, proximity of the voice). If it don't know who called it, and dont turn to verify (which i agree with previous comments, never turn your head away from the play), and DONT call the TO, time could expire with a frantic, red-faced coach yelling for time. Is there a circumstance when you would whistle the TO without turning to confirm it was the head coach?