Sending VOIPSCHOOL.ORG Back To School About HDVoice
mjgraves | July 22, 2009
Nothing gets my blood pressure rising like someone passing off bad or misleading information as the real deal. This afternoon I followed a link in someones Twitter stream over to VOIP School where there was a post about HDVoice dating back to mid-June. Go ahead and read it, that way you might come to understand my exasperation.
It makes me crazy when people start offering misinformation as if its gospel. Poor information wrapped in a nice looking blog is genuinely harmful. That’s what I found in the VOIP School post from June 17th. The title of the post is “HD Voice. The Future of VoIP?
Why so agitated you ask? Well, allow me to explain, based largely upon a comment that I left for their consideration. I’ll quote the more egregious bits from their June 17th post:
“HD transmits from about 50 Hz to 7,000 Hz”
Yes, but that’s the absolute minimum, worst case that anyone would consider a HDVoice call. Typical of G.722. Some codecs support audio bandwidth > 20 KHz. Yes, music quality.”
Additionally, since HD voice transmits more frequencies it takes up more bandwidth.”
That’s patently false, or at best misleading. Of the many wideband codecs out there only a few use any more bandwidth than plain old G.711 that we call PSTN “toll quality.” G.722, the oldest and most common wideband codec in hardware uses the exact same 64 kbps before packet overhead. Most use much less, some dramatically less.
Want to know more about the specifics of various wideband codecs? Here’s something I posted a few months ago; “Myth Busting HDVoice: Frequency Response vs Data Rate“.
“Also, users may have to invest in HD phones to get their full money’s worth.”
What kind of mealy mouthed wish-wash is that? If you want to experience a wideband call using a desktop phone you will need to buy one. That’s just common sense.
If you find a soft phone on your PC an acceptable alternative you might have to buy one of those. There are also open source & freeware options in that area. Some, Like PhonerLite for Windows, are wideband capable.
“While HD compatible phones do exist, some argue that they don’t deliver full HD voice quality.”
More drivel. You might have had a point, but failed to make it accurately.
Most wideband capable phones deliver real wideband quality calls. A few of the very cheapest might support a wideband codec for marketing purposes. It looks good on a tech sheet. But those same very cheap phones may not have the physical hardware quality to deliver a great sounding call.
The old Grandstream BudgeTone 200 is the classic example of this. While it supports G.722 you only hear an HD call on this phone using a headset. This is a simple case of getting exactly what you pay for.
“Even then HD to HD calls will be worthless if they have to travel over a traditional land line.”
Ahem, if the call path is via the PSTN – “a traditional land line” – then by definition it’s NOT an HDVoice call. HD calls require a pure IP media path. IP end-to-end. That usually means dialing by SIP URI.
In my case that means I have the pleasure of wideband calls between my associates desks. Also calls between offices routed via our WAN. Also calls home from a soft phone on my laptop to the Gigaset phones at my home.
We especially appreciate conference calls where its just simply easier to understand what’s being said. Heck, my dogs even recognize my voice over a wideband call to a cheap little ClearOne Chat 50 speakerphone plugged into my wife’s PC.
I applaud your effort to be informative with this site. To be credible you need to do your homework about topics like HDVoice. If you’re not speaking from personal experience using HD then you’re not well positioned to comment.
This post has very little useful information except to express your personal lack of enthusiasm about HDVoice.
Now, moving on to the July 2nd followup post entitled “HDVoice – The Technical Stuff.”
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