One common misconception that keeps coming up is the assertion that the higher quality audio available through the use of wideband telephony (aka HDVoice) requires more bandwidth on the network. This is simply not true.
The terminology gets confusing for some folks. On the one hand we’re talking about frequency response of the audio channel being much greater, 50 Hz to >7 KHz for most wideband codecs, as compared to 300 Hz to 3.4KHz for the reference standard G.711. All that extra information has to go somewhere, right?