[northernpenguin]

One thing that happened to me - Telus put this lovely hard plastic case on my phone to protect it, and I like that case - but what I found after I had problems with low earpiece (/microphone!) volume was that the tab on the plastic sheet that protects the phone was covering the speaker. Once I trimmed that sheet back down, both earpiece and mike started acting proper again. I believe the noise cancelling got confused.