more difficult to achieve, owing to the slow development of the ability to control return echo from the far end and the lack of speed in the connection between the two points. Slowly, as the technology became more readily available and the developers began to understand the issues, acoustic echo control became better and better. As audio, video and connectivity technology all improved, more manufacturers began to release devices to support the conferencing market. As a consequence, the complexity of the installed systems began to increase substantially. To wit, people began asking, “If I can use one box for eight microphones, then surely I can use four boxes to enable 32 microphones, right?” What originally was a complex room with eight microphones on a conference table has now become a 600-seat conference auditorium with 200 or more inputs. The $100,000 boardroom has become the $100 million audiovisual extravaganza, boasting a broadcast-style control room, behind glass, that’s in full view of the conference participants. Concurrent with this, it did not escape the notice of enterprise CFOs that they could have an equally satisfying, completely free FaceTime chat with their kids on their cell phones. The real question then became this: “Does the room sound $100 million better than my cell phone does?” We’ve all seen the results of transmission delay and latency in video. Just look at most live-TV news reports in which two people are tr ying to have a conversation in locations many miles from each other. One person asks a question and the video shows the delay in the person hearing the question at the other end, and then responding. Equally jarring are instances in which video and audio have different arrival times; often, this appears as bad lip syncing of audio and video. This problem exists in conferencing, and it’s often dependent on the quality of the connection and the quality of the endpoint. It’s compounded by the probability of multiple far ends, each of which has var ying audio and video arrival times. Tr y explaining to a CEO why his or her $100 million conferencing system’s audio does not match IT/AV Report
with the lip movement in the video. Good luck with that! We expend a great deal of effort testing to tr y to find an average delay time to help compensate for this non-audio issue. Our findings show that, psychologically, matching the voice with the lip movement improves speech intelligibility. One day soon, someone will show me a way to automate this process that can measure and account for all the variables. Hopefully, someone is working on that problem! We have all learned over time—especially through familiarity with our cell-phone technology—to discount minor glitches in audio and video. We’ll dismiss them as connection problems, and we’ll even resort to reinitiating a call to see if things improve. However, in a big, expensive conference room, there’s far less tolerance for connection issues. This typically results in opening a ser vice call/ticket, even before redialing a call is attempted. The problems are frequently related to an issue at one of the many far ends; for example, one person reports he or she cannot hear well, even though ever y other far end is just fine. This is not, and it never will be, an issue that can be resolved by adjusting the transmission side of the audio. Speaking of mobile phones, their typically lesser-quality audio—especially with calls from noisy environments—has contributed to decreased audio performance in conferences. That being said, two ways that cellphone sound has improved are (a) by using headsets and (b) by using sophisticated, in-car infotainment systems with cabin microphones and speakers. Many of the problems with audio can be linked directly to microphone type and placement. Originally, small conference-room systems had microphones on the table in front of the person talking. Simple speakerphones were positioned on the desk in front of the user. Lectern microphones were located directly in front of the presenter, and each person on the dais had a microphone placed directly in front of him or her. All these had the advantage of microphones being placed a short distance from the source of the
sound—the talker’s mouth. Regrettably, minor improvements in microphone technology are now constantly being oversold by manufacturers’ marketing departments—in many cases, directly to architects and business owners—resulting in the unreasonable expectation that technology can correct for the “annoying” physics of sound. When we’re told by an architect that we cannot place microphones on the table or on the ceiling in front of the conference participants—indeed, that the only acceptable location is on the ceiling behind the heads of these people—one has to wonder what the architect is thinking. AV consultants are in a difficult position because saying “no” to an architect puts further work from that firm in jeopardy; unfortunately, that can leave no one to argue the case for properly placed microphones. (The architect, of course, points to the marketing materials that say there are microphones on the market that can work in those locations.) Let’s examine that hype. I, personally, have listened to and measured the results of these claims of bending and/or altering the laws of physics. I can honestly say that the obvious point remains true: The farther away you place the microphone from the person talking, the less effective the resulting audio will be. Even though it is quite obvious to ever yone in the audio business, it might be news to some manufacturers and consultants that, when people talk, the sound comes out of their mouths and not the backs of their heads. We shouldn’t have an expectation that a microphone can pick up sound clearly from that position. I can attest to this personally. During live demonstrations at trade shows and during various video presentations I’ve viewed, I’ve listened to microphones that supposedly track people speaking around a room. I’ve been told by manufacturers that the voice quality is the same when you talk directly at these devices as when you face away from them; it never is, though. The problem is that people who don’t take the time to test for themselves believe the claims about the products. This has become so
What the future holds for unified communications and collaboration is featured in our fall edition of IT/AV Report.