Wideband Voice refers to the use of Wideband Codecs in Digital telephony. Wideband Codecs use higher sampling rates than Narrowband Codecs or utilize embedded sub-band coding techniques to effectively increase the bandwidth of the baseband voice, from the traditional 200 Hz to 3.5 kHz used in Narrowband Codecs, to 50 Hz at the low end and anywhere from 7 kHz to 22 kHz [1]. at the high end, depending on the type of codec used. This results in a significant improvement in voice quality since it allows the wideband codec to transmit consonants, sibilants and other subtleties of the human voice formerly lost by narrowband codecs and significantly adds to the intelligibility and quality of the speech signal.
In addition, some wideband codecs may use a higher bit-depths of 16-bits to encode samples, also resulting in much better voice quality.