adworld
join:2004-10-06
Auburn, ME
| [Primus] What determins GOOD voice quality?
what EXACTLY determins good voice quality?
I understand you need good bandwidth both up/down... min to zero packet loss... and good ping times... But what about the ATA device? there seems to be tons out there. Is it fair to say the cheaper the ATA device the worse the voice quality will be?
Does voice quality rely heavliy on the providers setup/eq? I mean you hare a lot about provider X having horrible voice quality and or loss of dial tone. And you will hear this from may different people, but yet there is always a few people w/ little to no problems... how can this be?
If someone could shead some light on this topic for me that would rock!
david |
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sgarrand
Insert Witty Phrase Here
Premium
join:2000-04-13
West Brookfield, MA
 ·Callcentric
·VOIPo
·QuantumVoice
 ·Charter Pipeline
 ·1and1
| The reason some people have problems and others don't would most likely be their internet connection. Stability and reliable speeds are required for good voice. I suppose there could be cases of faulty adapters, but I'm sure it's usually the person's connection causing the problems.
If you have the necessary speed, no/low latency, and a stable connection everything should work fine. If not, it's on the provider's end.
Scott
--
Visit »whythehell.com, FWD number 48043, QuantumVoice user with an UNLIMITED residential toll free number for $42, »QuantumVoice.com/rates_800.shtml |
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xrandom
You
join:2001-02-21
MA
| reply to adworld
good voice quality for me is that my calls sound as good as my cell phone. I haven't experienced many problems with lingo BUT i only use it as a secondary phone because I am waiting for my port to go through. I try to use it as much as possible as well as get my family to use it as much as possible but until the port goes through thats just not going to happen as much as I want.
So I guess the more you use it the better the chance you might experience problems. I am also not a power user anymore (not enought time) so my connection to the internet is not maxed out very often. |
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XPat
Well...Okay
Premium
join:2003-02-24
Fort Myers, FL
| reply to adworld
said by adworld  :
what EXACTLY determins good voice quality?
Try »www.testmyvoip.com . It gives you a graphic of your VoIP quality. Makes test calls to some VoIP test servers, I guess.
Another thing that determines voice quality is the codec in use. Some compress voice more to use less bandwidth which can degrade voice quality.
Think of your favorite Led Zeppelin riff compressed at 32 kbs or at 360kbs, or a jpeg of Miss October at 90% compression.... or 10%.
I use Vonage at its highest setting (90 kbs) and it is as good as my POTS. Since I am not sending it a Christmas card, I don't remember the codec's name (guess: g711). Somebody here will know the differences among all the different flavors.
John |
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sgarrand
Insert Witty Phrase Here
Premium
join:2000-04-13
West Brookfield, MA
·Callcentric
·VOIPo
·QuantumVoice
·Charter Pipeline
·1and1
| said by XPat :
Since I am not sending it a Christmas card, I don't remember the codec's name (guess: g711). Somebody here will know the differences among all the different flavors.
John
Here is some info about audio codecs: »www.voip-info.org/wiki-Codecs
Scott
--
Visit »whythehell.com, FWD number 48043, QuantumVoice user with an UNLIMITED residential toll free number for $42, »QuantumVoice.com/rates_800.shtml |
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testr773
join:2004-05-18
WA
2 edits | reply to adworld
you need
A stable internet connection, with decent bandwidth
A good voip codec, g711 is what you want
Insist that your voip provider disable silence suppression
Good audio quality demands more bandwidth. Uncompressed codecs sound better, high bandwidth connections typically have better network characteristics (low latency, jitter, packet loss) + consequently sound better. Good audio will require about 12KB/sec (100Kbps) with low jitter. The most commonly perceived problems are tinny or warbly audio and delays in the conversation where you start to talk over the other party. As a consumer there are three main things that you can do. Find a decent internet provider. It is usually the upstream bandwidth that is critical. Providing that you have enough bandwidth, ask your voip provider to use the g711 codec. And insist that tech support disable the silence suppression (sometimes called voice activity detection). The use of lower quality codecs and silence suppression are bandwidth saving measures.
There are differences between terminal adapters in how jitter buffers and protocols are implemented but these are small differences compared to the choice of codec and getting rid of silence suppression. For me the line delay is highly aggravating, more so than the codec quality. Trying to get your voip provider to disable silence suppression will tax your patience.. you may have to call five or more times before you even find a tier2 tech that knows that the feature exists.
<further reading> |
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ejrobinson
Premium
join:2003-05-16
Miami Beach, FL
·magicjack.com
| The g.729 is a good performer. I have both vonage, which uses the g.711 and lingo, which uses the g.729. Quite often I get better voice quality with the lingo. Note that I have 8meg/704k bps, so my bandwidth is more than sufficient for either.
-er |
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caseydoug
join:2001-08-14
Seattle, WA
| reply to testr773
Good explanation. As to bandwidth requirements, however, a good rule of thumb is that you need about 160kbps of upstream bandwidth for uncompressed G.711, and about 50kbps for G.729 or one of the other compression schemes. Double that if you plan to use 3-way calling. So you buy quite a bit of bandwidth for a small drop in perceived fidelity. In fact, unless you have bandwidth to spare, the call quality is likely to be better using compression. The RTP used for VoIP data streams does no error checking, so if bandwidth is inadequate, the packets are simply dropped.
I found this explanation helpful:
»cnscenter.future.co.kr/resource/···ment.pdf |
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adworld
join:2004-10-06
Auburn, ME
| »www.testmyvoip.com/results.html?···result=0
this is what I got around 2:20pm on Sunday... using the boston test
»www.testmyvoip.com/results.html?···result=0
this test was around 2:29 on Sunday using the San Jose test
I live in Maine...
but so what I am hears is codec and bandwidth are the key componets for good voice quality... |
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wiggles4
join:2004-10-09
Eugene, OR
| reply to adworld
Re: [Primus] What determins GOOD voice quality?
I was curios about how the different codecs performed as well, so I made some test samples. There really is a lot of difference between them, however, all three are perfectly intelligible.
G.711 (Vonage High, Call Vantage)
G.726 32k (Vonage Low)
G.729 (Packet8, BroadVox) |
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adworld
join:2004-10-06
Auburn, ME | now with the different codecs... I know different devices support different codecs, but do differente providers allow/support different codecs? can u request a specific codec? |
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caseydoug
join:2001-08-14
Seattle, WA
1 edit | The Lingo/Primus servers support both G.729A and G.711A(PCMA), but Lingo allows you to use only G.729A for its unlimited residential service. I suspect that Lingo's business service may use the higher quality CODEC, but that's just a guess. |
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ejrobinson
Premium
join:2003-05-16
Miami Beach, FL | It's the other way around. Lingo uses the g.729 for the residential service.
-er |
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caseydoug
join:2001-08-14
Seattle, WA
| said by ejrobinson :
It's the other way around. Lingo uses the g.729 for the residential service.
To quote our President, "I knew that!"  |
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wiggles4
join:2004-10-09
Eugene, OR | reply to adworld
Is it more costly for a VOIP provider to use a larger codec? Do they need to allocate more bandwidth somewhere? |
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caseydoug
join:2001-08-14
Seattle, WA
| said by wiggles4 :
Is it more costly for a VOIP provider to use a larger codec? Do they need to allocate more bandwidth somewhere?
Yes, I think so. With G.711, the packets are not compressed and therefore consume more bandwidth. That's why I'm guessing Lingo charges more for business class service. Businesses are also likely to have a faster internet connection, and therefore can accommodate the uncompressed CODEC. |
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wiggles4
join:2004-10-09
Eugene, OR
| That's what I figured, although, I'm still trying to figure out exactly how much the VOIP provider touches your packets. They at least have to have a server somewhere (in every area code they support?) to accept the call and transfer it to the PTO network. If that is the case, then I would assume that they could support many more users in that area code with a codec that compresses more.
That does seem to hold up since all the providers that charge more then $20 are those who use G.711. |
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testr773
join:2004-05-18
WA
| reply to adworld
g729a sounds okay
if all of your other ducks are lined up. To me g729a is comparable to a decent cellular call, provided that you have a good isp and you managed to disable VAD. g711 is landline quality, in fact telcos can and do use g711 on landlines. For my money, the extra delay caused by VAD and the slight clipping of the words is what really detracted from the lingo call quality. My g711 broadvox line is markedly superior in both voice quality and uptime. But calls to Europe cost a lot less with lingo. |
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wiggles4
join:2004-10-09
Eugene, OR | Does the g.711 spec not include VAD? |
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caseydoug
join:2001-08-14
Seattle, WA
| said by wiggles4 :
Does the g.711 spec not include VAD?
The settings are independent. You choose your CODEC, and then you choose to enable or disable VAD. |
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