How Noise Cancelling Technology Works



We've all heard of noise cancelling headphones, which seem to magically block the outside world and protect us in an audio cocoon. The same noise cancelling technology applies just as well to office conference rooms, where background noise like HVAC systems and passersby can ruin a productive meeting for the far end listeners. In this handy guide, we've shared the main types of noise, how noise cancelling technology works in an office environment, and why it matters to your business.

Types of Noise

There are four main types of noise, which require different digital noise cancelling technology to neutralize and explain how noise cancelling technology works. Below, we've shared a brief overview of each type:
  1. Continuous Noise: This constant din is usually produced by equipment that never turns off, such as a vent or heating system. It can pervade a conference call with an annoying hum that becomes hard to ignore.
  2. Intermittent Noise: This noise type comes and goes, but it's arguably more distracting than continuous noise. For example, it might be a passing subway train or timed equipment that turns on periodically.
  3. Impulsive Noise: Unlike intermittent noise, this type tends to be much louder and unexpected. For example, if the property next door is under construction, you might hear the occasional thud or jackhammer that comes out of nowhere. It's difficult to prepare for impulsive noise, especially in a conference room setting.
  4. Low Frequency Noise: Finally, this common noise type refers to the low-frequency background sounds that we're constantly exposed to in modern life. Cars driving on the highway, power plants producing energy, and distant crowds can all produce low-frequency noise.

Why Noise Cancellation Matters in the Office

Noise cancellation matters in the office because it's one of the best ways to create an effective meeting space. Even in a high-rise building with thick glass windows, the outside world can pervade your office with all four noise types. Meanwhile, office equipment like air conditioners, light fixtures, and networking gear can add continuous and low-frequency noise to your space. All of these unwanted sound sources can build up to create a wall of noise, which can cause distractions in an important conference or meeting.

How Noise Cancelling Technology Works

Noise cancelling technology functions as a combination of several technologies. Essentially, the best microphone systems and conference phones have DSP ("Digital Signal Processing") technology built into their hardware. This algorithm processes the sound source and cleans up the signal before sending it to its destination. For example, many Yamaha products include Human Voice Activity Detection (HVAD), which identifies and isolates human voice frequencies from any background noise that the microphone picks up. The combination of these ideas is how noise cancelling technology works.

There are two main types of noise cancellation:
  • Passive Noise Cancellation: How does passive noise cancellation work? Simple: It works as any physical measures that clean up a sound signal and prevent noise. For example, some headphones have an in-ear design that blocks outside sound, just like an earplug. The best hardware is designed with passive noise cancellation in mind, so that minimal DSP technology is necessary, which is how noise cancelling technology works.
  • Active Noise Cancellation: By recording the background noise with a microphone and then playing it back with the original signal 180 degrees out of phase, you can cancel most of it out. This active process can also be achieved with filters, depending on the hardware design.   

To simplify the installation process, every Yamaha UC conferencing product includes built-in DSP functionality that can handle any meeting environment. For example, the YVC-330 portable conference phone can run DSP algorithms in real time, including Acoustic Echo Cancellation (AEC), gating, and patented SoundCap Technology. With a dedicated DSP chip, you can enjoy the best possible audio quality, regardless of the room's acoustics.

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