How beamforming works: making the conference phone a smarter listener
Beamforming technology makes the conference phone a smarter listener, actively improving the sound quality of your distance meeting. The technology helps to pick out the right audio data for processing and refinement using intelligent algorithms. We take a look under the hood of Konftel's new generation OmniSound® with beamforming.
Beamforming is a signal processing technology where, instead of sending signals in all directions, the signal is directed towards the user. A good example of beamforming in everyday use is a WiFi network, where you want to focus the signals on the person using the network at that specific point in time. The main benefit of using beamforming in an audio product is that the technology can be used to pinpoint the sound source that people want to listen to, making it better able to refine the desired sound, while simultaneously filtering out any other sounds that get in the way.
In essence, beamforming helps to direct the attention of the microphone where it is most needed. This means that you can reduce the perceived distance between the teleconference participants. If the person speaking is standing at a whiteboard four meters away, the beamforming will make it sound like the speaker is only two meters from the device, cutting the distance in half.
With the help of beamforming, Konftel can halve the perceived distance from the listener, so that a person speaking four meters away will sound like they are only two meters away to the person at the other end of the conference phone.
Knows where the microphones are
The audio improvements are possible because the system always knows the exact location of the microphones that are picking up the sound. Although sound travels at a speed of over 340 m/s at room temperature, the technology can still detect the time difference when the sound hits the different microphones and then perform the desired signal processing using an algorithm. If, as with the Konftel 800 conference phone, you have three microphones around the edges of the phone, the direction of the sound can be tracked 360 degrees around the device.
With three microphones fitted into a conference phone, it is possible to determine the direction and distance of the speaker and then process the sound in order to considerably improve the experience.
The triangular positioning of the microphones naturally makes the algorithm and the calculations more advanced than having all the microphones in a row, for example, but it also makes it easier to determine exactly where the speaker is located, and that information can be used to boost the desired sound and so halve the perceived distance for the listener.
Many unknown parameters
Beamforming for a conference phone is still quite a challenge, with a number of unknown parameters coming into play. Even if you know exactly how the built-in microphones behave in relation to each other, both the speaker and the conference phone could be anywhere in the room. The conference room could also vary in its design, with better or worse acoustics and disturbing background noise. When working on audio for a hands-free system in a car or on a laptop, it is reasonable to assume that the person speaking is most likely going to be around the same distance from the microphones every time. In the case of a car, you will also know quite precisely how the background vehicle noise will affect the sound.
With a car or a laptop, you can therefore work on the basis of various assumptions, which make your audio processing calculations that much easier. But this is not the case in a conference room. All these unknown parameters make beamforming much more of a challenge for a conference phone, but success brings a huge reward in the form of better audibility – particularly compared with a conventional solution in a large conference phone with multiple built-in microphones, where you might attempt to optimize the sound by switching the microphones off and on.
Konftel is something of a pioneer in audio for conference phones. It was over 30 years ago that the company launched its OmniSound®, delivering full duplex and flowing dialog without irritating sound clipping, damping or echoes. Although Konftel now also offers video solutions, sound is still a core focus, which is why, as a key component of Konftel's technical advancement, the next generation of OmniSound® with beamforming has been incorporated into the Konftel 800 and the Konftel Smart Microphone.