A report published by iLounge revealed that microphone found in the Wi-Fi only and 3G iPad 2 has a major difference in quality. The report said that microphone of the Wi-Fi only iPad 2 offers better audio quality.
According to iLounge, this quality difference can be contributed to the materials used to build iPad 2 units and their positioning. Padgadget reports:
The difference in audio quality may have to do with the different placement of the microphone on the WiFi and 3G models. On the WiFi version, the microphone is located above the iPad’s front facing camera towards the edge of the aluminum body. The microphone is located in the same spot on the 3G version but due to the slightly redesigned body, it sits in the iPad’s plastic cellular antenna shield. The different materials around the microphone opening, and the fact that the 3G version has additional components located by the microphone, may be to blame for the difference in audio characteristics.
The audio quality in AT&T and Verizon iPad 2 is “slightly muffled and echo-prone” and these flaws are more present in the CDMA version.