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HD Voice and it's mythical fears
by Ruben 
You have heard nothing until you have experience HD Voice (Wideband Audio) - even on equipment that does not physically support HD Voice.
The first time I experience HD Voice where by using two Snom telephones. Quality was very good, better than using G.711. Then exchanging the standard Snom receiver with their Klar Voice - and was literally blown away.
Due to the increased focus on HD Voice theses days, there will always be a lot of "nay-sayers" around. These people will write and say things that might not be quite true - or they will state right out speculative non-issues.
Actually, these people are spreading wrong information and myths.
The PSTN myth
Because all telephone signals sooner or later travels over PSTN lines - or over VoIP - the quality must suffer.
The first part of this myth is partly true: When you have to send your voice signals over the PSTN network, the quality will suffer, how much depends on the terminatin network of the other party. Given the right equipment, and the right line quality (i.e. ISDN) - G.711 quality is quite good.
I am a bit amazed that no-one has said anything about how bad the quality of HD Voice will be when sending the voice stream over a GSM network. Most people, even non telecom people, know that the quality of the GSM network is inferior. The anti HD Voice people knows that they will be caught with their pants down IF they bring that argument to the table. Unfortunately they try to project their "PSTN quality is bad for HD Voice" onto VoIP.
However, that argument is pure scare-tactic.
Also cell phone related: The difference in quality between a GSM phone (cell phone for those readers from the USA) and a ISDN line (or even a analogue line) is comparable to the difference in quality between G.711 and G.722. No one in their right mind dismissed the cell phones due to the lack of sound quality.
More and more people are switching over to VoIP - and I seriously doubt that any VoIP provider worth their weight will NOT provide HD Voice sooner or later.
HD Voice is VoIP. Period.
The bandwidth myth
Due to the increased spectrum used by HD Voice, the bandwidth will increase.
Fact: A typical ISDN line (one B channel) can carry 64 kilobits per second. The G.711 codec is considered to be "ISDN quality". In fact, if you are using ISDN, you are probably used G.711.
Fact: In 1987 the International Telecommunication Union (ITU) passed on a standard called G.722 which was designed to run over ISDN lines. This was more than 20 years ago.
The ISDN of 1987 and the ISDN of 1997, and of 2007 - and let's not forget 2009 is still 64 kilobits per second.
The protocol overhead for a G.711 call, and a G.722 call, or a G.729 call passed over the Internet is still the same. G.722 does not magically increase the bandwidth even if the quality is dramatically much better than G.711.
Another fact: G.722.2 is the codec chosen by the 3GPP Consortion. If it's good enough for mobile hand sets - it should be an very strong indication with regards to the amount of bandwidth it uses.
The network myth
HD Voice is so much more complicated than other VoIP protocols, that the current crop of router will have problems with buffering.
This myth is really a variant of the bandwidth myth. There is really no more complexity for the network layer in a codec supporting a wider spectrum, than a codec supporting a lower spectrum.
If I take the liberty to make an analogy: When you did download this web page - your wifi router did have much more problem giving your computer the graphics on this page, than the text. Anyone who knows anything about computer networks will laugh at this notion.
A byte is a byte, no matter if the byte contains <HTML> or binary picture data.
I am no math major - but in my book it is logical to assume that the less processing one have to do with a signal, the easier it is to work with the signal. Please prove me wrong in the comment section so I can learn a thing or two.
The quality myth
The quality of HD Voice is not much better than ISDN quality.
This is a statement I only see from people in markets not having ISDN - thus hard to prove wrong by the readers.
For your convenience: The spectrum used by ordinary telephone systems, the so called narrow band codec systems, is between 300 and 3500 hertz. As far as I know, the human voice works in the range from 80 to 14 000 hertz (give or take).
The Wideband in Wideband Audio goes from 30 hertz to 7 000 hertz or more.
The numbers here speak the truth. If you can't see that 7 000 is the double of 3 500, then you should be quiet.
The investment myth
People have invested too much into VoIP telephone equipment, so they will not invest into HD Voice enabled equipment.
Even if this myth seems to have something to it, it's only a matter of time before it will die a quick and painless death.
As more and more enterprises, but also private citizens, invest into VoIP - they will want the best there is. Given the price for a G.722 enabled Siemens Gigaset - there is no reason not to choose non HD Voice equipment.
The interop myth
There is a lack of interoperability between hand set vendors - they all use different codecs.
As with all new and emerging technologies it will take some time before everyone is speaking with everyone else. Fortunately the G.722 family of codecs are well defined, and given the focus Wideband Audio is having these days, no vendor will go astray and "invent their own twist".
On the other hand - I have not seen any indication that there are HD Voice enabled equipment are not supporting the basic G.722 codec.
The sound myth
Hearing all the surrounding noise details will kill the usefulness of having better sound quality.
I have saved this myth for end of this posting.
This is also the only time where I am going to use the words how stupid can you be.
The argument is pure stupidity.
The added sound quality might also introduce more noise to the conversation - but this is a minor inconvenience compared to what you are getting: nearly the same quality as if you where sitting face to face with the person you are having a telephone call with. How cool is that?
If the nay-sayers are concerned about surrounding noise on a G.722 call - how about the noise when you are actually sitting face to face with someone? Is that noise also to be considered bad?
22/07/09 01:30:23 am, Feedback awaiting moderation
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