Phone.com is a sponsor of HD Voice News
At IT EXPO East 2010, Phone..com CTO Alon Cohen gave a relatively clear demonstration of the difference between “SD” voice (in the form of G.711) and HD voice with a pair of sound clips using the same spoken phrase.
To hear the SD G.722 voice clip, click here.
To hear the HD G.722 voice clip, click here.
For a visual representation, Cohen had a couple of nice slides illustrating the differences between the two codecs in terms of sampling rate and CPU & bandwidth usage–
Unfortunately, the graphics themselves get a little “jaggy” (i.e. not high quality) when shrunk down to fit a typical web page.
The audio and slides examples were presented as a part of a larger Microsoft Powerpoint 2007 presentation, available for download in .PPTX format here.