Focus on Technology: Overhead Microphone Systems

Your ears are really good acoustical measurement tools. Sit in a space alone sometime, clear your mind, and see how many different sounds you can identify. Very often, you will be able to pick out five or six sounds and then your ears will find the background noise level, which covers over the rest.

Performing this exercise will make you aware of familiar noises that are a regular part of your daily environment; the ones your brain has become accustomed to, thus tuning them out. However, in a new environment, your brain doesn’t immediately filter out these commonplace noises. When you travel, how well do you sleep that first night? If you are like most of us, you toss and turn, waking up every time you hear the door close down the hall or a bus drive by.

Microphones used in audiovisual installations for distance learning or conferencing are like your ears and brain in an unfamiliar setting: they pick up everything. Unlike your brain, a microphone or other audio components can’t make decisions about what to filter out – it can’t selectively tune out what the people on the other end don’t need to hear. Subsequently, the system transmits a lot of extra energy and unneeded information. The connection carries all this data / traffic to the far end for the listeners to try to sort out.

In lieu of a smart microphone that can selectively listen like a human being, a favored option is a microphone that can be positioned where it will pick up more of the desired sounds from the lecture or meeting, and less of the extraneous sounds. We have found a ceiling mounted system has proven a very worthy tool in this regard. The ceiling system contains a large clear acoustical barrier which keeps the noise from the ceiling out of the microphone and uses the other side to direct sound to the microphone element. We have found it a better all-around option than boundary microphones or goosenecks. The barrier minimizes the noise from the ceiling, which is the primary challenge with other ceiling microphone systems. All ceiling systems helps minimize the noise from computers fans and shuffling of papers that table top microphones more easily pick up.

A good microphone system, in conjunction with other good design procedures and acoustical engineering solutions, has allowed us to set up rooms that have satisfied some very critical listeners at the far end. Using the overhead boundary systems, critical listeners have stated that from the far end, the room sounds as good as – if not better than – the broadcast news.