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Lo-Fi Phones and the Future
bossanovalithium writes "Back in 1936 — 74 years ago — boffins accepted that about 3.3Khz was the accepted frequency that telephone calls are going to run on and it's been like that, generally, ever since. Call quality is reasonable but leaves a lot to be desired. Think calls from Skype to Skype where quality is often crystal clear." It's crazy to me that (for people with decent mics at least) Ventrillo sounds better than corporate conference calls.
I live in 3rd world country and our major cellphone networks support hd-voice codecs.
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I can't even read the referenced article but I can tell you the phase ""Back in 1936 — 74 years ago — boffins accepted that about 3.3Khz was the accepted frequency that telephone calls are going to run on" is totally wrong.
What they meant to say was that the relevant bandwidth for understanding speech would be from 100Hz to 3.4kHz. Making the required bandwidth be 3.3Khz.
So how many boffins died to bring 3.3Khz to our phones?
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the problem has been solved yet not been implemented widely. It's called ENUM and freely available and open. No need for proprietary XConnect stuff to implement this functionality, it's based off DNS and thus already has a widely available penetration. All people (and large corporations) need to do is actually use it.
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I was pondering this exact stuff just today at work, since a phone call sounded kinda crappy, barely acceptable until I needed to involve 2 more people and put it on speakerphone, it became so bad we had to give up. I dropped the phone call, switched to skype, and damn what a big difference. The crappiness of POTS is ridiculous indeed, and although I see the need for compatibility, it can't die soon enough.
By the way, if you like Ventrilo, try Mumble, which, apart from being free and open source, which can't hurt according to the /. crowd, has really awesome sound quality, and you can setup your own private instance in minutes. Plus, for the MMO crowds, it has extremely low latency, awesome echo echo echo echo cancellation and built-in auto volume normalization (helpful when That Loud Guy Without Headphones keeps pressing his PTT and everyone's in pain)
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I don't have an issue with the frequency range, but certainly do with latency, and the lack of true duplex any more!
I find (found) that talking on a true analog line is MUCH easier than any digital line today - be that Skype, cell phones, or even land lines in most countries. I'm always amazed when traveling abroad when I make a local call on a truly-analog system how much nicer the experience is!
With today's systems in "Westernized" countries, you can't even have an effective 2-way conversation. The duplex performance sucks - you can't hear anything while you're talking. Add to that a small but noticable delay, and you have to resort to long pauses between sentences to ensure you don't talk over one another.
Am I the only one that notices this? It's AWFUL compared to what it was like 20 years ago.
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I've been working with VoIP in enterprise environments for a little over a decade. Latency is indeed a real issue and has to be considered, however it's not as restrictive as you might think. Generally speaking, if your ping is 150ms round trip you will not be able to distinguish a delay during an audio conversation, unless you're in the same room with them. Latency up to 300ms round trip is generally considered acceptable.
Cell phone conversations may or may not utilize VoIP during some legs of their calls. If they do, it's not between the phone and the tower unless you're using Skype or some other 3rd-party application on the phone. There is a distinction between encoding/decoding analog voice and how the digital signal is transmitted; you cannot consider cell phone calls to be synonymous with VoIP even though they do share some characteristics.
While cell phones do have highly variable horsepower in the CPU, the encoding/decoding is handled in purpose-built hardware chipsets, not on the CPU. It's unlikely that the type or brand of phone has any but a negligible difference in latency. Most people do not notice the latency in cell-to-cell conversations, so it may be that you're more sensitive to it for some reason.
Another factor is that some of the widely-deployed audio codecs used to compress voice were built and tuned for English speakers. Those speaking very dissimilar languages, such as Mandarin, may find that audio quality is poorer even on the same equipment.
Lastly, there are defined codec standards for wideband audio. Cisco has been including them on all their phones for several years; I assume other VoIP manufacturers have as well but do not have personal knowledge. I found that some customers did not like using them, as they are accustomed to hearing some level of white noise in the background and are prone to misinterpret a period of silence as call disconnection. If you've ever asked "are you still there?", the clarity of the call was greater than you expected or, possibly, wanted. Even with normal quality codecs we've had to inject comfort noise for years.
Little of the above applies to video. That's a whole different story.
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Latency of the call is highly variable, and dependent on two factors:
1. How much latency is in the network?
2. How much latency is introduced by the VoIP conversion itself?
I joined Vonage about 5 years ago. On my first ISP, I got a little over 3/4 second of latency on a really good ISP connection. This was annoying, but not enough to really make me want to spend two and a half times as much for a landline with a non-portable number. Eventually, Vonage went through a stretch of upgrades to the firmware on my adapter and the latency dropped to about 1/4 second (all but unnoticeable). However, I traveled a lot a couple of years later and found that hotel connections tend to have a lot more latency, so I got a cheap prepaid cell for when I was on the road. I settled down to a local job again and had a lot of trouble with my new ISP for a while, resulting in poor call quality and very high latency, then we got that straightened out and I was back to 1/4-second delay, which was pretty much the rule until my company issued me a cell phone with unlimited minutes, so I ditched my Vonage line because I didn't use it. But friends who have joined since have reported very low delays, almost unnoticeable, as long as their connections were good.
So the technology has improved, but you are still dependent on someone who gives you the better tech, and on a good Internet connection between you and the adapter on the other end where the call is bridged back to a POTS network.
However, landlines have a few features that people have a hard time giving up. Whether you are willing to pay for them is a different matter.
1. No need to manage power to a device. If the wires are up, the connection is the telco's responsibility.
2. Real, honest 911 with pretty much 100% accurate location awareness. Your tax dollars at work (which are a generous chunk of the difference between telco and VoIP).
3. "Feedback loop" (you can hear yourself talk in your earpiece). This helps regulate your volume, which is why people tend to talk louder into cellphones (they don't get that feedback).
4. No-delay talking. When telcos use VoIP, they use really high-end gear and fast networks to support it.
5. True DTMF support. This has gotten a little better, but VoIP for the most part can't carry DTMF tones to sufficient clarity, so your local VoIP adapter has to recognize an attempt at one and generate a fresh tone that your analog gear can recognize. Conversations with people can occasionally be interrupted by a "BEEP" as your VoIP adapter misidentifies a sound in their voice or the background as a DTMF tone and faithfully reproduces it, and you may get occasional complaints of the same issue on the other side . If it fails to reproduce when needed and you run a menu system, your customers will really hate traversing your menus.
The net result of all of that is, well, you get what you pay for. Telcos are expensive, but you are pretty much guaranteed a good call every time. Most of the gear you probably own was built to analog specifications, and the telcos are good at maintaining that spec.
For most of us, cell or VoIP is sufficient. We're OK with slight delays, a less-than-perfect reproduction of our voices, the occasional errant DTMF tone, etc.
If you run a business and you strongly feel that clear telephony is a vital part of your business, then it's probably worth paying for in your case, or at least paying for a REALLY good Internet connection and high-end VoIP gear, not consumer-grade stuff. Though you could always run one VoIP line for a while and see how it works out (just use it for less critical calls to start with).
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An MIT student did his thesis on Voice vs. Data lantency on cell phones, you might be interested in his methodology and results:
Quality of Service Analysis for Audio over Cellular Voice Networks