HD voice Last modified: Monday, May 12, 2008
Short for high-definition voice, and also called wideband voice, in Internet telephony, it refers to the use of wideband technology to provide a deeper clarity and better audio experience in VoIP communications. Traditional telephony is based on sampling the sound stream 8,000 times a second, and constraining the reproduction of the sound spectrum to the range between 200Hz on the low end to 3.3KHz on the high end—and fitting it into a 64Kbps bandwidth. In HD voice, a wideband codec doubles the sampling rate and more than doubles the width of the sound spectrum reproduced, from 50Hz to 7KHz. This adds significant depth and nuance to the transmitted sound—and it reduces the bandwidth requirement to 32Kbps, half that of PSTN transmission. HD voice technology uses Digital Signal Processing (DSP) technology to capture and transmit the higher quality sound. Several wideband codecs currently being used for HD voice include G.722 and G.722.1, and the MPEG-4 AAC Low Delay codec. See also "High-Definition Voice: The Future of Phone" on EnterpriseVoIPplanet.com. See also "The Difference Between VoIP and PSTN Systems" in the "Did You Know..." section of Webopedia.
•E-mail this definition to a colleague• For internet.com pages about HD voice . Also check out the following links! Enterprise VoIP Planet  The IT Manager's Guide to Voice over IP High-Definition Voice: The Future of Phone  What is "high-definition voice"? There are two ways to answer that question: by analogy, and with technical specs. Webopedia's "Did You Know...?" Section  Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software. Webopedia's Quick Reference Section  Use this Webopedia reference section for information on common Internet and computer facts and occurrences.	Internet Telephony Standards Telecommunications codec G.721 G.722 G.7xx MPEG-4 PSTN sample rate sampling VoIP wideband Give Us Your Feedback Shopping HD voice Products Compare Products,Prices and Stores Shop by Category: Other Network Devices 9 Model Matches Network Cables 5 Model Matches IP Phones 8 Model Matches Hard Drives 1 Store Offers Voice Recorders and Transcribers 2 Model Matches