Time To Make Phone Calls Sound Better?

In the amazing advance of technology of the past half century or so, there’s been one unfortunate constant. The audio quality of phone calls today is pretty much what it was in the mid-1930s. Just about everything involved in the transmission of phone calls during that time, but because the public switched telephone networked is locked into audio protocols that allow just 3 kHz of bandwidth, voice quality is frozen in time.

A loose confederation of hardware makers, software companies, and service providers, including tele- and videoconferencing specialist Polycom, voice-over-IP chipmaker DSP Group, and VoIP service provider phone.com is aiming to change this. Flying under the banner of Connect HD–yet another bad analogy to HD television–their plan is to take advantage of abundant bandwidth and digital technologies to improve voice quality.

They make a good case. Human speech typically ranges from about 80 to 14.000 Hz, but traditional phone systems chop off everything below 300 and above 3,300 Hz. That’s a wide enough frequency response to provide intelligible speech–barely, but our brains are remarkable good at making up for what our ears don’t hear. Most of the time, we can differentiate between a “b” and a “p” sound over the phone, even though the audio cues that make the difference between these voiced on unvoiced plosive consonants live in the higher frequencies that are lost over phone circuits. HD Connect wants to provide at least 7 kHz of frequency response, though this can often be provided in less actual bandwidth through the miracles of digital signal processing.

HD Connect is wisely not trying to impose a single standard. It will support multiple codecs–the software that encodes and decodes audio as digital signals so that two HD Connect handsets, speakerphones, or other endpoints should be able to negotiate a common protocol. Where necessary, systems such as conference bridges can convert, or transcode, signals.

Both intelligibility and overall audio quality of speech were greatly enhanced in the HD Connect demos that I tried. There was also a much great sense of presence, the feeling that the person you are talking to might  actually be in the same room. In a conference call, individual voices are much easier to differentiate and some accents are much easier to understand.

Still, I think the HD connect folks face a tough road ahead. We have managed to create a wireless phone system that reproduces the miserable voice quality of the landline network it is rapidly replacing. The wireless carriers are not about to change their protocols, which in any event would require all of us to replace our mobile handsets. in theory, we could all be making VoIP calls on our smartphones, and with VoIP, software alone can determine the audio quality. But the wireless carriers have a vast investment in voice infrastructure and terrible quality or no, they are not going give it up without a fight.

My guess is that Connect HD technology will make its first inroads in what amount to walled gardens, such as speakerphones and conferencing systems that run on internal corporate VoIP networks. For telephony at large, however, lousy audio quality, though easily preventable, is likely to be with us for a long time to come.

6 Responses to “Time To Make Phone Calls Sound Better?”

  1. Jeff Rodman Says:

    A great description of HD Voice, and what it can do! And take heart, the world is moving even faster in this direction than it may at first look. Every major VoIP phone maker is shipping HD-capable phones – in my own company’s case, Polycom, we don’t build any VoIP phone that can’t handle HD anymore. Major enterprises are going HD on their internal networks, and Europe is moving even faster – Orange has over 500,000 HD public subscribers already, and has even introduced cellular HD Voice. Here in the US, there is a quickly growing flock of carriers including Verizon Business, Global Crossing, Cox, IP5280, many more and the list keeps growing.

    The cordless phone makers are all building HD-capable phones as well – any phone with a media player is already HD capable, by definition. And a dominant wireless HD Voice codec, AMR-WB, was co-developed by Nokia.

    What’s made this possible so quickly is that when phones go digital, as they already are on wireless and now on wired connections, the network becomes transparent. The network really doesn’t care whether the signal represents narrow or wideband audio – it’s just another kind of data, and modern HD Voice doesn’t even take any more data than old voice. So if you have a call between two phones that both support HD Voice, talking over a conventional VoIP network, you can easily get a real HD connection.

    Your point about the walled gardens nails the real missing piece. VoIP gardens, numerous and increasingly huge, are rapidly advancing to replace non-VoIP telephone networks, but they need to be able to talk together. We need our carriers and service providers to work out how to call each other’s subscribers. They’ve been doing that for decades in PSTN. They just need to replicate the same process for VoIP and the network will be open to VoIP, HD Voice, even dial-up videoconferencing and services of all sorts.

  2. Alon Cohen Says:

    Let me add that it could well be that the wireless carriers might be the first to jump on the HD Voice wave. Users are replacing wireless phones relatively fast.

    For modern phones like iPhone and others the HD capability is already there and might be switched with a software update. If the phones will not do HD over the “normal” channel they will do it as part of the data network using VoIP.

    On top of that, the few wireless providers already experimenting with HD, found out that churn is reduced when users used HD phones and hence HD will become a strategic marketing tool for them.

    When (and not if) those wireless islands start moving into the HD arena, everyone who has not done so, will loose market share.

  3. Steve Wildstrom’s skeptical take on HD Voice « HD Voice News Says:

    […] full blog post is here, […]

  4. John Taylor Says:

    On a recent trip to Italy, I was astounded at the voice quality on my Verizon/Vodaphone Blackberry within Italy — almost Skype/Broadcast quality. I couldn’t believe is was the same handset I was using back here in Virginia. I’m assuming it’s all due the bandwidth allowed me.

  5. Internet Phone Service Says:

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  6. rankpay promo code Says:

    Google Voice is a lifesaver. I can’t believe the functionality that it offers, take for example the ability to screening calls. I’ve got some invites if anyone wants any. Also I hope that Apple rethinks the GVoice App, hwo could such an awesome application get not accepted by Apple?

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