2011 135iC bluetooth microphone

Hi all - I have a 2011 135i convertible and the bluetooth microphone has never worked well. I can hear the other end crystal clear through the speakers but people tell me I sound like I'm in a tunnel and the sound is muffled. Dealer blamed my blackberry, so I sucked it up for a year. Now I have a new Droid 4 and have the same issue. Brought it to a different dealer, and they replaced the microphone but told me that the issue is in the design on the 135 conv and there isn't anything they can do. My brother-in-law has a convertible Toyota (!!) and my sister says his phone calls are flawless but she can't hear me. I find many complaints on various models but I don't see a solution. What do I do next? Try yet another dealership? Is the problem inherent in the design or is there an issue with my car?

I also have a 2011 135 convertible but everyone has told me they can hear me very clearly. I have an iPhone 4.

Thanks for the reply -- I'll borrow one and try it out to see if that changes anything. I'll be surprised if it does.

The BMW bluetooth system seems to not have sufficient noise cancellation technology for a convertible. The system in my M Roadster elicits similar disdain from those on the other end of a phone call. By contrast, the system in my 128i works beautifully even with the windows down.

I'd suggest giving Halston at Bavarian Soundwerks a call for some advice on the retrofit microphone possibilities.