iPhone 4 earpiece seems muffled?

[twynne]

I'm now on my 2nd iPhone 4 (due to this issue) and the sound has had the same issue on both phones. I fear it's a casualty of the new design and the only options are to return the phone and wait, or learn to live with it.

 

[Floydian]

I have experienced this issue as well. I've heard that it's another i4 hardware defect.

 

[sebastian...]

I realize this is an old thread, but the problem remained on iphone 4s. Mine is muffled with bass and no treble lacking high frequencies.

Did anyone made a comparison between different iphone 4 models ? or iphone 4s ? Are all the same ? Is this by design ? Is is worth to exchange it ?