Know Your Sound Tool
Know Your Sound Tool: Active Noise-Cancelling
September 4, 2019
In our ongoing series featuring the design and technical aspects of our wireless earphones, headphones and speaker, we speak with members of our product team to learn more about what goes into the engineering of our premium audio products. In this feature we will discuss Active Noise-Cancelling (ANC), a noise suppressing technology that is infused into our latest and most technically sophisticated headphones yet, the MW65 Active Noise-Cancelling Wireless Over-Ear Headphones.
What is Active Noise-Cancelling?
Active Noise-Cancelling is a technical feature built into sound tools used to eliminate unwanted external noise by producing an equal and opposite sound that ultimately cancels it out.
What is the difference between Active Noise-Cancelling and Passive Noise-Cancelling?
Passive Noise Cancellation refers only to the naturally-occuring noise cancelling properties that a headphone itself offers, simply by virtue of its own structural design without any electronic assistance. Things like carefully fitted ear cup padding help passive noise cancellation for over-ear headphone models, however most are only able to cancel out high pitch sounds. Active Noise-Cancelling takes noise cancellation one step further, by using a system of electronic microphones to detect environmental noise and create an equal and opposite ‘anti-noise,’ thereby eliminating unwanted external noise before it enters the ear canal.
How does Active Noise-Cancelling work?
The fundamental premise of ANC is fairly simple. Active Noise-Cancelling works by measuring and analyzing the sound of your surroundings, producing the exact opposite sound and playing it back to you in real time to eliminate unwanted noise. This means you can hear only what you want to. Our ANC technology is achieved by combining feedback and feedforward microphone systems, often referred to as Hybrid ANC, which collectively work to cancel noise ahead of entering your ears.
What’s the difference between feedforward and feedback systems, and why does Master & Dynamic use both?
When we talk about feedforward and feedback microphone systems, the fundamental difference is the placement of each microphone. The feedback microphone is placed inside the ear cup, whereas the feedforward microphone is placed outside.
Master & Dynamic has worked to develop an innovative feedback and feedforward microphone system that eliminates noise without compromising sound quality. An external microphone (the feedforward microphone) works to cancel out noise, especially higher pitch sounds. Simultaneously, an internal microphone (the feedback microphone) is responsive to change and constantly self-corrects to cancel-out lower pitch sounds. Together, they create a zero-noise environment, which allows for an optimal listening experience.
What are the different ANC modes and what kind of environment are they best suited for?
The MW65 Active Noise-Cancelling Wireless Headphones feature two levels of active noise-cancelling, as well as the option to use the headphones without ANC.
High Power: This setting is best suited for high-noise environments like airplane cabins, trains, cafés, busy commutes and general travel. While using High Power, both the feedforward and feedback microphones work to cancel unwanted noise.
Low Power: This setting is best for windy environments. When someone is outdoors and it’s particularly windy outside, the outer microphone can become overloaded by wind, overwhelming the feedforward ANC system. Choosing Low Power mode turns off the feedforward microphones so that only the internal feedback microphone is on, allowing the ANC system to work properly.
ANC Off: Choose this setting for when you want to enjoy your headphones but remain aware of your surroundings. This setting offers passive noise isolation, which allows the listener to enjoy our signature sound while remaining alert to the environment.
What are some of the challenges when developing and implementing ANC?
Implementing ANC in a way that works for everyone is technically complex, especially when taking into consideration all the variables and environments that exist. What’s more, noise cancelling gets even more complicated when you have to take into account the various elements within the headphones that also create noise. Things like built-in acoustic drivers, ear pads and microphones all affect how active noise-cancelling works, and in turn need to be neutralized and cancelled out.
All of these variables can ultimately lead to an active noise cancelling system becoming unstable, especially if it’s poorly designed. Unstable active noise cancelling can make squealing noises, similar to what it sounds like when someone points a microphone at a speaker on stage. Rest assured we took all of this into account when designing the MW65 Active Noise-Cancelling Headphones to ensure they do not become unstable.
Discuss the technology and the innovation that the MW65 offers.
Typical active noise-cancelling headphones forgo audio quality in an effort to reduce cost and prioritize noise cancelling. The MW65 Active Noise-Cancelling Headphones do not sacrifice sound quality. We use a custom Beryllium driver, which is a material with an incredible stiffness to weight ratio. This allows for huge low-frequency output without sacrificing high-frequencies, and ultimately creates a richer sound. If you’d like to know more about Beryllium, click here.
The design for the MW65 was streamlined to give a slim appearance when worn. Typically to achieve a slim headphone profile, engineers and designers would rely on steel to attain the necessary strength for everyday use, which adds weight. Every aspect of the MW65 was redesigned to use forged and CNC-machined super-high grade alloy aluminum instead, which significantly reduced the weight of the headphones, allowing for an incredibly slim profile when worn.
Learn more about the MW65 Active Noise-Cancelling Wireless Headphones by clicking here.