An Engineer Explains the Magic of Bose’s New Headphones

Editor’s Note: The Bose Noise Cancelling Headphones 700 ($400) were released this past summer and are available for purchase now. Be sure to read our full review, here.

There’s been a ton of hype around the new Bose Noise Cancelling Headphones 700 ($400) — and for good reason. The company that essentially created the category of noise-canceling headphones, and has been a leader in the space, claims that the Headphones 700 are “the biggest leap forward in headphones” since the original QuietComfort 3 that was released back in 2006. And that’s a big promise.

The Headphones 700s are not intended to be the next generation of the QuietComfort 35 IIs and therefore will not replace them; Bose will continue to sell the QuietComfort 35 IIs, which will be the more viable option for more budget-conscious shoppers that don’t want to spend $400 on the Headphones 700s. Bose is not expected to change the price of the QuietComfort 35 II ($350), however, you can find them frequently discounted on third-party sellers like Amazon or Best Buy.

So what does the $50 price jump get you? A new digital signal processor, new audio drivers inside, a new eight-microphone system and they now charge via USB-C. Bose claims that Headphones 700s are better at noise-cancellation and sound better than the QuietComfort 35 IIs (if maybe only slightly), and they have all-new transparency mode. The biggest difference, however, is with voice — the Headphones 700s promise drastically improved call quality and clarity, for both you and the person on the other line, whether you’re in a quiet room or a crowded coffee shop.

To find out more about the Headphones 700s and why they are potentially revolutionary, we chatted with Dan Gauger, a senior engineer at Bose who has been working on noise cancellation headphones for the better part of three decades. We touched what makes the Headphones 700s so special, why anybody would buy the QuietComfort 35 IIs now, and what the future of headphones looks like.

The following interview with Dan Gauger has been edited for brevity and clarity.

Q: The Headphones 700 look drastically different than any QuietComforts. Why the shift?
A: If you look historically, every QuietComfort headphone that we’ve made up to QC35 has had a core design. We changed details [over the years]. We added things like Bluetooth. We added extra microphones to the noise canceling. We approved lots of other details and changed, in fairly small ways, the industrial design, total options and things like that. But the core stayed the same. We just kept making it better and better.

Two things were decided when we started developing the Headphones 700. One, is that we’d reached the limits of what we could do with that platform and we wanted to do more. And the other thing was the industrial design. The core design of the QC35 dated back to 2003 — we wanted to make it better.

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Q: Can you talk about this design and how it came about?
A: We started by giving the industrial design team pretty much free reign to propose a variety of ways of designing it. And they came up with, I think, three concepts. And we looked at them, and tested them and selected the one that became the core of Headphones 700. In doing that, the ear cups got thinner and flatter. The whole attachment to the headband changed.

Q: And how did those changes impact things like sound quality and noise-cancellation?
A: The engineers had to figure out how to achieve the noise-canceling performance of the QC35 and improve on it where they could. Which involves rearranging some details and acoustics on the inside. We needed to develop a whole new speaker driver, in order to not violate the goals of the industrial design, and it needed to be smaller in diameter. We made it a little taller in some spots but it was a whole new speaker.

A key background thing to keep in mind is that, in order to make noise canceling work well, you have to make as much noise as you trying to cancel. And we’ve always prided ourselves on headphones that can handle a lot of low-frequency sound. You know the kinds you encounter in many transportation situations, riding subways, for example. And if it’s for [a speaker with a] smaller diameter, it can’t push as much air so you have to make it move more in order to get the output you need. And, of course, that’s also critical for bass.

Also keep in mind that the speaker we use, the driver, reproduces both the canceling sound and the audio you’re listening at the same time. And so we wanted to make sure that we could do that, and do that cleanly with less distortion while making the speaker drivers smaller. And that ends up giving the Headphone 700 a cleaner sound in even more challenging conditions.

Q: Got it. What about the new microphone array? How is it different from the QuietComfort 35 II and what can it do?
A: Sure. For noise canceling, the Headphone 700 has got six mics. There’s one on each side your head looking into your ear canal and two on the outside that are listening. The standout feature with this microphone array is voice pickup, however, so in that case we have two microphones on the outside of each ear cup, one of which is shared with noise canceling, so there are three total on the outside each ear cup; two on each cup are intended to be used for picking up your voice.

Q: So how exactly does that work?
A: What’s actually done is a multilayered process for extracting your voice from the noise. We use all four signals, two on each side of your head, to get a clear sense of your voice, essentially aiming an array at your mouth. We use them differently to look around you and get a sense of what the general noise coming from all directions is around you. We also look for strong sources near you, such as a person sitting at a nearby table who is talking loudly. And we take all three of those things and figure out how to give you the cleanest signal that we can of your voice and project as much it as possible. So it’s a multilayer process to attack the noise and deliver your voice to people, at what we call the far end.

Q: Sounds complicated!
A: OK, yeah [chuckles]. There’s this phenomenon in psychoacoustics that we all naturally adjust how loud we talk based on the noise we hear. You go into a loud bar and you’re naturally going to raise your voice. You know, you can feel it in your throat. One of the things that makes voice pickup a challenge for noise-canceling headphones is that you’re canceling the noise around you so you naturally want to talk softer. But that makes it harder for the headphone to deliver your voice to the [person you’re on the phone with]. This is a significant factor.

For example, when you’re wearing something like Apple’s AirPods ($159), you’re naturally going to talk louder because they do nothing about the noise. But with a noise-canceling headset, you talk softer. The voice pickup job just got harder! With great voice pickup like the Headphones 700 delivers, you can talk softly, so you have a sense of privacy in a public place. You can be sitting in Starbucks with the Headphones 700 on and talk more softly and comfortably. The person at the far end hears you clearly and not the noise around you. But then the third point is that because you’re talking more softly, the people around you don’t overhear what you’re saying.

Q: Gotcha, so there’s this trickle-down effect.
A: It creates the possibility of being private in public. And we’ve been testing them recently, and its really, really cool. You can sit like in our cafeteria. I did a test a few weeks ago with some colleagues. In our cafeteria for lunch hour and put on the headphones and have a great conversation. The people sitting five or six feet away have no clue what you’re saying, let alone barely even hearing you’re talking.

Q: So is this new call pickup feature and the new transparency mode two different things?
A: Yeah. Yeah. So transparency is about using the noise cancellation differently. You know how when you plug your ear your voice gets all boomy? It’s called the occlusion effect. So we use the part of the noise canceling device while looking into your ear to cancel that ‘boomingness.’ Then we use the microphone on the outside to reintroduce the sound of the world in a way that sounds as if you have nothing on your head. And this creates a very natural experience of hearing everything. And again, it’s like the headphones become acoustically transparent.

Now on top of that, we give you the ability to adjust how much of the world you let in. So you have this controllable noise-canceling. I’ll describe the use case. Imagine you’re a parent and you’re at home and your kids have got friends over. You’re reading a book while monitoring what they are doing, but they get too loud. You don’t want to break from reading, so you can put on the headphones and basically turn them down. It’s like making mental space for yourself. You can push them off into the distance but be very aware. You can choose how loud they are.

Q: That sounds pretty cool?
A: Yeah. So all of this is a first step in ‘super powering’ your hearing. And we’ve got more things coming along those lines over the coming of, over the coming years and I think we’re really going to be eyeopening.

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Q: With the arrival of the Headphone 700, why would someone choose the QuietComfort 35 IIs over the 700s now? Does it just come down to price?
A: Well, I’m shuffling as I think about how to answer that because I always go back to thinking about myself. I’ve got, I tend to use QC35 when I’m sitting somewhere like at a desk or in my living room. And of course, I’m lucky because I can buy them easily. And I’ve got QC35s scattered in about three places in my life and I’m gonna replace all of them with Headphones 700 because of the voice pickup and the transparency, foremost.

Why would someone go for QuietComfort 35 II? My guess is that it would be because all they want is the headphones for the traditional sense: disappearing into their music or their movie or whatever audio they want. Maybe they don’t talk on the phone that much. And maybe they liked the classic styling they’ve come to know on our QuietComfort line. And if that all they cared about, save some money in buying QC35. If you want to read into the future that we’re describing, go for a Headphones 700.

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