Callers say my voice sounds muffled when using bluetooth.

Nope! Bluetooth works brilliantly. Like most things posted here, it no doubt is user error.

I have the same problem with my Motorola H780. It seems to be intermittent but it is enough to tick my wife off.

Yes, It has been reported many times. Hopefully a software update will fix this for everyone.

Same here. Even the rep for Iphone said I sounded like I was on a tunnel. I am so dissapointed on this product. I has so many issues. I am thinking of returning it.

I'm having the same problem. Callers are now telling me I sound like "I'm talking through a pillow". I have a Jawbone...

Thanks, I just reported it as well.

Yes it is a problem. 3G was a problem 3GS was a problem and Iphone 4 is the same. Nothing changes. Guess you have to hold it a certain way or reset it.

Get a bumper it will fix it. LOL! Just kidding. My jawbone works fine, no muffled voice here.

I have the same problem with my plantronics 925. It doesn't happen all the time but it does frequently. The headset has no problem when paring with iPhone 3GS or Sony Ericsson phones. It's definitely iPhone 4 compatibility issues. Seriously need help. I heard people are having the same problem when using Jawbone Icon too! That is ridiculous.

Same problems here with Jawbone Icon. There are several threads going on the Jawbone forums. If you care to have a look see.

http://forums.jawbone.com/t5/Troubleshooting-Tips/Icon-and-iphone-4-static-white -noise-amp-muffled-voice/m-p/3965/highlight/false#M1339

Can a few of you help me with a test? I have a Jawbone 2 & a Jawbone Icon. Both exhibit a strange behavior with my iPhone 4. If either of these headsets are on, paired & connected AND a call is answered or initiated, things are fine.

When it all goes downhill is in this scenario:

My headset is OFF. I receive or make a call and mid-call, I decide to turn on the headset (which I keep off to save battery). The Jawbone connects and automatically switches the iPhone from PHONE to JAWBONE. This is all normal right? Okay here's the problem. The call quality has static, sounds muffled and the caller tells me I sound like I'm in a tin can. If I then switch back to the phone (through the iPhone page of Sources) and then back again, to the Jawbone, most times--quality is back to normal. Obviously this is not something we all want to be doing. Can anyone do this test with their headset .. any brand and even some of you with Icons? It would be good to know if the culprit is the Bluetooth Headset or the iPhone. Remember, it's important that you make a call with your Bluetooth headset in the OFF position and then turn it on mid-call to use it.

Don't waste time to test. No point. It's already narrowed down by people including me that whenever there is an incoming call, the Bluetooth cannot send our voice correctly. The contrary is different and works well... strange.

Yep, I have this problem with my Pro Plantronics headset.

100% of the time when I receive a call on my headset, callers say they can barely hear me.

100% of the time when I place a call while using my headset, callers say I sound great.

It's an incoming call problem some how. For some reason, I suspect the fact that I can hear my phone ring through my headset when receiving calls, has something todo with the problem. Maybe the bluetooth profile used to ring the headset is different then if you place a call.