updated 04:19 pm EDT, Thu September 13, 2012
Issue linked to different CDMA technologies
The iPhone 5's wideband audio support won't extend to Sprint, spokesperson Michelle Leff tells Phone Scoop. Wideband audio is better known as HD Voice, and delivers clearer call quality. Sprint's implementation of HD Voice is carried over CDMA 1x Advanced, however, whereas most carriers are supporting it through WCDMA.
Apple has said that at the launch of the iPhone 5 next week, 20 carriers worldwide will support its brand of wideband audio. That number should increase in relation to the number of international rollouts, which will grow steadily towards the end of 2012 and to a lesser extent during 2013.