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Jeff Rodman
Polycom Employee

When was the last time you used a conference phone? Today, or perhaps yesterday? It probably hasn’t been more than a day or two. Open-air voice conferencing is as ubiquitous as with the traditional handheld or headset - maybe even more so for many of today’s businesses.


soundstation-ip-7000.jpgOver the last two decades, the name Polycom has become synonymous with voice quality – indeed, the company is still known as the world leader in high-performance audio communications. The iconic triangular form and Polycom® HD Voice™ clarity have become the standard of choice for boardrooms globally, and we continue to introduce innovative new developments in audio processing, noise reduction, system integration and human interaction which deliver a new level of transparency and reliability in today’s global conferencing environments. 


To ensure maximum efficiency and productivity during conference calls, it is critical for the speech to be easily understood.  We’ve all had the experience of struggling to work out what someone is saying - because of noise, or their distance from a microphone, or just an unfamiliar accent. Yes, our minds are good at compensating for missing words and blurred sounds, but the more time our brains spend in figuring out what the words were, the less well do we understand what they actually said, as shown in this short video. Therefore, it is vital that the physical “what we hear” stage be as clear and as accurate as possible.


There are five aspects of speech audio that work together to make or break a clear, understandable conversation: Bandwidth, Reverberation, Amplitude, Interactivity, and Noise. These five elements, taken together, are called the BRAIN model of practical audio communications. The job of a conferencing system is to tune and balance these elements automatically to provide the best and easiest experience for the parties on both ends of the call.


Let’s take a look at each of these characteristics and what they mean for conference phone users. 




  • Bandwidth: The Plain Old Telephone System (POTS) most of us grew up with carries less than half the information in human speech, and this shortcoming was unthinkingly brought over into early IP telephones.  However, newer system that implement HD Voice carry twice the bandwidth, greatly enhancing intelligibility, and this makes conversation much easier to follow and less fatiguing.   There are standards-compliant IP phones and conference phones that deliver this much higher audio bandwidth with amazing clarity that rivals the best video systems, making it seem that you are in the same room as those on the other end of the call. 
  • Reverberation:  Room echo at either end of a phone conversation makes the sound die down more slowly and smears words together. While a “perfect” solution will include acoustic wall coverings for absorption, wall-mounted diffuser panels, and personal headset or lapel mics for every participant, this problem is much more easily helped by using a multiple-microphone conferencing system which can intelligently steer and focus the pickup patterns to dynamically match the location of each talker in a room.
  • Amplitude: Insufficient amplitude, or loudness, can make it difficult to hear a talker. Moving the talker and listener are obvious solutions, but not always practical. There are conference phones which can automatically adjust microphone gain to greatly help in these situations, and the difference in ease of understanding can be breath-taking.
  • Interaction: Interactive speech between distant groups can be difficult to conduct for a number of reasons, one of which is the absence of a true full-duplex system, which allows transparent interactive speech. A conference phone with good full-duplex technology will enable the talkers at both ends to be heard clearly without any delays or distractions.  This is a feature to be careful of, as many speakerphones today have started to claim full-duplex performance, but it’s a very sophisticated feature few can actually deliver.
  • Noise: Common noise sources share much of the same audio spectrum as speech, and can make it difficult to understand conversations. To resolve this, first try to fix noise at the source. Move the microphones farther from air conditioner ducts, overhead projectors, coffee makers, and so on. There will always be residual noise, but HD Voice technology found in high quality conference phones makes a big difference in ensuring that voices of all participants on the conference call are clearly heard in spite of the acoustic challenges in the room.

So the next time you plan or join a conference call, consider the elements of the BRAIN model.  Remember that they work together: each BRAIN component can compensate for deficiencies in others, and this can be very important because some are much easier to address than others (consider the cost and difficulty of soundproofing a room compared to simply slipping in a better IP speakerphone with HD Voice and steered microphones, for example).  You can learn more about the BRAIN model from our whitepaper, downloadable from here.


The on-demand webcast about Polycom's new breakthrough solutions is available for replay. Watch it now.

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