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Your Next Phone in HD

If you've ever been on a conference call and found yourself torn over whether to interrupt the disembodied speaker and ask him to repeat himself because you weren't quite sure what he said about your latest project, you're not alone.

Your Next Phone in HD

If you’ve ever been on a conference call and found yourself torn over whether to interrupt the disembodied speaker and ask him to repeat himself because you weren’t quite sure what he said about your latest project, you’re not alone.


Jeffrey Pearl (left) and John Scarborough (right), founders and managing partners of Englewood, Co.–based conferencing and telephony provider IP5280, expect that in a few years, HD voice will be the only game in town.

If you’ve ever been on a conference call and found yourself torn over whether to interrupt the disembodied speaker and ask him to repeat himself because you weren’t quite sure what he said about your latest project, you’re not alone. What started as a simple convenience—being able to call into a meeting from around the country or the world—has evolved into common application that enterprises are seeking to improve on. Today, fresh technology acronyms, such as AMR-WB and AAC-LD, describe a trend toward wideband audio, a better version of standard conferencing technology that’s steadily replacing narrow-band in a variety of pro AV applications.

“You have some of these powerhouses like Polycom behind it,” says John Scarborough, co-founder of and managing partner at IP5280, an Englewood, Colo.–based provider of enterprise voice over Internet Protocol (VoIP) telephony services that sells Polycom conferencing gear. “A year or two down the line, [HD voice] will be all they’re talking about.”

At the same time, wideband audio is also showing up in mid-range products, which means it can tap a wider market—small and medium businesses (SMBs).

“It’s not just the most expensive phones,” says Jeff Rodman, voice division chief technology officer at Pleasanton, Calif.–based Polycom. “It’s now in the middle of the market.”

Wideband audio piggybacks on the trend toward VoIP. By 2010, roughly half of small and two-thirds of large enterprises in North America will use VoIP, according to Boston-based Infonetics Research. “In terms of the cost and the ease of maintenance for all network equipment, VoIP would be a beneficial choice for many different businesses,” says Fumihiko Kawamura, product manager for videoconferencing at Sony Professional Solutions. “Once companies make a transition to VoIP from the ordinary telephony system, they can easily control and manage all network resources.”

So what exactly is wideband audio and why might customers want it?

Wideband audio often is used interchangeably with terms such as “HD conferencing” and “HD voice,” which are either generic terms or brand names, depending on who’s using them. For example, Polycom uses “HD Voice” to refer to its wideband products, while Vapps, a Hoboken, N.J.–based conferencing provider, dubs its services “HiDef Conferencing.”

All of which often leads to confusion for prospective end-users. “It’s not very well understood,” says Ben Lilienthal, Vapps’ founder and CEO. “[HD voice] is being used as a generic catch-all.”

HD video offers an analogy: Although most consumers and enterprises have heard of it, few know the difference between, say, 720p and 1080i or know that the majority of today’s HD TV programming is actually upconverted SD. So like consumers who assume that owning an HDTV automatically renders everything in HD, some enterprises don’t understand that there’s a whole ecosystem of hardware, services, and standards necessary to deliver an HD conferencing experience.

In general, to enjoy a wideband audio experience, organizations already running VoIP also need:

  • VoIP phones that are capable of HD voice and implement a wideband codec (see “At a Glance: HD Voice Standards”).
  • An HD-aware IP-PBX or service provider, often just a software upgrade to a normal VoIP PBX.
  • A bridging service, either as part of the IP-PBX or service provider, or through a separate HD voice bridging provider.

“To the extent that it translates to a dramatically better user experience, users know what HD voice means,” says John Lightfoot, vice president of engineering at Broadcore, a Los Angeles–based provider of VoIP services for the enterprise market. “What they don’t generally know is that it’s only meaningful in an IP-only environment between endpoints supporting the wideband codec.”

Indeed, VoIP isn’t just an enabler—it’s the secret sauce. That’s because it can inherently deliver conferencing audio that’s noticeably superior to older, analog technologies. VoIP can pick from a wider assortment of wideband-audio codecs, such as G.722, whereas the public switched telephone network (PSTN) is limited to elderly narrowband technologies. Wideband audio achieves higher quality audio because it has a wider frequency range. For example, G.722 picks up, or samples at, 7 kHz worth of human speech’s audible range. By comparison, the old-school telephony standard of G.711 takes in only about 3.4 kHz. Newer VoIP codecs pick up even more. MPEG-2 Advance Audio Coding Low Delay (AAC-LD) provides CD-quality audio by sampling at 20 kHz.

The wider the range, the more nuances that are picked up and transmitted to the listener, including high-frequency consonants such as “s,” “f,” and “th,” whose presence or absence can make the difference between understanding a caller’s every word and asking them to repeat themselves. This is especially important when using wideband audio to address conferencing’s limitations in today’s organizations.

For starters, many companies are already promoting teleworking. With conference calls a more regular and critical business practice, the demand for high-quality calls increases. But more important is the international nature of many enterprises. Whether out-sourcing or maintaining foreign offices, larger organizations using conferencing applications must be sensitive to language and dialect. Although wideband audio isn’t a cure-all for the language barrier, it can help.

For example, at traditional “toll-quality” telephony rates of about 3.4 kHz, high-frequency sounds such as “s,” “f,” and “th” can get washed out. That can force some conference participants to strain to understand what others are saying. Depending on the language, subtle differences in consonants can also affect a word’s meaning.

“People who are native English speakers, their mind will fill in the sound of an ‘s’ or a ‘th,’” says Peter Nutley, director of global product marketing at New York–based Tandberg. “Especially in international applications, it makes a huge difference to [go] beyond toll quality to be able to discern those differences.”

As wideband audio becomes more common, integrators face design and troubleshooting challenges. A big one is ensuring quality of service (QoS). For example, if conference calls are routed over an enterprise’s local area network (LAN), the switches and other infrastructure must have QoS mechanisms capable of putting voice ahead of more delay-tolerant traffic such as e-mail. If the existing LAN infrastructure doesn’t support QoS, it can be either a barrier to VoIP adoption—and wideband conferencing—or an opportunity to upsell the customer.

“The biggest problem we have in this business is the customer’s LAN environment, whether it be home office or large office,” says IP5280’s Scarborough. “A lot of this stuff is not VoIP-ready, so we help consult to get that were it needs to be.”

Another challenge is the enterprise’s security mechanisms, particularly firewalls, which often block audio and/or videoconferencing traffic. That’s why many conferencing vendors have spent the past few years adding firewall expertise and products.


A variety of standards provide the foundation for today’s wideband audio systems. Here are the main ones, along with a few other key players.

  • AAC-LD. Based on the MPEG-2 Advance Audio Coding (AAC) spec, AAC-LD’s suffix reflects its low-delay requirements: no more than 20 milliseconds. AAC-LD provides CD-quality audio and samples at a rate of 20 kHz. “We think that AAC-LD will be more widespread, especially for VoIP phones,” says Sean Lessman, senior director of advanced technologies at Tandberg. “There’s a reason for that: It’s very high quality. It outperforms all of the other codecs in that space. And there’s been some recent adoption by very large manufacturers, [including] Apple, Texas Instruments, and Cisco.”
  • G.711. G.711 is an old-school telephony standard. Approved by the International Telecommunication Union (ITU) when Richard Nixon was still president, G.711 samples speech at 8 kHz. Wideband systems generally fall back to G.711 for those users who are calling into a conference from a traditional, non-VoIP phone.
  • G.722. Standardized by the ITU two decades ago, G.722 samples speech at 16 kHz. That rate is faster than traditional telephony networks, making for a noticeable improvement in clarity and dynamic range. But G.722’s bit rate is the same as G.711, so the additional quality doesn’t increase the network’s workload. G.722 also is attractive because its patents expired years ago, so vendors don’t have to pay royalties to use it.
  • G.722.1. Standardized in 1999, G.722.1 provides the same audio quality as its predecessor but at half the bit rate, making it attractive for networks and applications where bandwidth is limited, expensive, or both. It is licensed by Polycom.
  • G.722.2. Also known as Adaptive Multi Rate Wide Band (AMR-WB), G.722.2 samples speech at 16 kHz and is the standard used in a growing number of today’s third-generation (3G) cellular networks and mobile phones. That adoption is noteworthy because cell phones are often the weak link in conference calls. So as more wireless users upgrade to handsets with AMR-WB, there’s less chance that it will be a wireless caller dragging down the whole conferencing experience. Or at least that’s how it’s supposed to play out.

“I think conditions in the wireless world are so adverse to call quality, any codec designed for that environment will probably aspire to mere toll quality and not HD—at least for now,” says John Lightfoot, vice president of engineering at Broadcore.

If the conferencing system supports G.722.2, then it can communicate “natively” with AMR-WB cell phones instead of using transcoding. “Transcoding costs you [processing power], and it adds degradation,” says Jeff Rodman, Polycom’s founder and CTO of its voice division.

Yet another challenge is the broadband connection a telecommuter is using for the conference. Because those links are outside of the enterprise, it’s difficult to control latency, jitter, and other QoS-related factors. One option is to deploy equipment at each remote office or telecommuter’s office that calculates mean opinion scores (MOS), which are widely used in wired and wireless networks to assess voice quality. IP5280 deploys routers from Santa Clara, Calf.–based Edgewater Networks that collect MOS data for each link, maintain a history of the quality of all calls, and can be configured to send an alarm when call quality drops below a certain point.

But some argue the value of MOS diminishes if the enterprise also does videoconferencing over that link. “In a purely audio-only world, MOS scores work,” says Sean Lessman, senior director of advanced technologies at Tandberg. “But there hasn’t been anything solidified for how to do MOS scores for audio and video at the same time.”

One thing that no one debates is that wideband audio is another example of why AV integrators increasingly need skills in IP and networking if they want to continue to sell into the enterprise market. “You have to become a LAN expert,” says Jeffrey Pearl, co-founder of and managing director at IP5280.

Wideband audio isn’t the exclusive domain of installed systems. Vapps, for instance, offers a managed HD service using Skype, an Internet program famous for allowing consumers to make free or cheap calls online. Integrators often get pushback from enterprises that wonder why they should pay a premium for, say, a pro-grade LCD display when they believe the consumer models at Best Buy are just as good. There’s a similar situation with wideband audio, where some enterprises—particularly small ones—believe Skype’s do-it-yourself HD Voice is a good, low-cost alternative to a pro system.

Integrators, therefore, need to identify companies that require more than just cheap, high-fidelity calls. “I’d say we’re selling a business class feature set and not HD only,” says Lightfoot. “If a customer just wants a single line with HD to talk across the world to another HD-enabled line, it’d be hard to beat a couple free lines configured on softphones. If the customer wants a business-class PBX replacement, that single line and software won’t cut it.”

Even so, cost is an issue, especially for SMBs, which increasingly are drawn to VoIP providers not for wideband audio, but rather for the opportunity to have PBXs and other services that once were the domain of large companies.

“We let the SMB guys have the quality and services that have been available only to enterprises,” says Lilienthal, whose PC-based HD conferencing services run $25 to $200 per month. As in any pro AV application, the solution itself will depend on the client’s requirements. Fortunately, the latest wideband audio technologies come in shapes and sizes to fit most organizations.

Tim Kridel is a freelance writer and analyst who covers telecom and technology based in Columbia, Mo. He can be reached at [email protected]

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