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.

Comments

Bandwidth not Frequency

[RichMan]

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.

How many died?

[0racle]

So how many boffins died to bring 3.3Khz to our phones?

Right on the spot

[Gruturo]

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)

Re:guess what

[Anonymous Coward]

Ludicrous Definition? Pffft.

Here in Scotland, our TV definition has gone plaid.

Re:Latency?

[Anonymous Psychopath]

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.