Exclusive: How Apple made the 15-inch MacBook Air

Laura Metz: The Air is known for having this amazing feature set and awesome combination of performance and portability. It’s not just about being thin and light but also having amazing battery life so that you can use the device wherever you want to go throughout the day. And as we look at the market landscape, we've got a huge population of PC laptops that have 15-inch displays. And so we know that we've got users who don't necessarily need the performance of a MacBook Pro to get that larger display. They just don't necessarily need all that capability and performance, and so with Apple silicon it was a great opportunity to look at this. 

Kate Bergeron: We worked very closely with the folks on our display team to understand how we can optimize the number of panels we can fit on a large set of the motherboard glass. And so, we knew we wanted to be in the 15-inch range, but we got the opportunity to push all the way out 15.3 inches because we could cut the other glass to that size. So, it's nice that we could hit this sweet spot and even go just a tad bigger, which our customers will really appreciate. 

Kate: We honestly started by setting our target of can we make a 15-inch laptop that is the same thickness as the 13-inch? It's not as easy as in the in the video when you hit the pinch to stretch and it just magically gets two inches bigger. One of the big things that the team really had to focus on is reliability performance and durability over that large screen size. The display where the LCD needs to be structurally really sound. And so we use a structural adhesive to attach the panel to the chassis piece that we call the display housing. 

Kate: Why don't we talk about the speakers? We were able to add two more woofers to the 15-inch versus the 13-inch and we are using that larger screen size to afford us that ability. We offset the force-canceling drivers in the width of the product because we have to take advantage of that larger footprint. In addition we want to balance as big of a trackpad we can put into the product while also remembering that we want to have the great battery life that an Air has.

So just to boil it down really quickly, the larger screen demands a little bit more power. So we have to increase the battery size accordingly, because if we don't we wouldn't hit the battery life targets. So we're able to use the bigger product to grow the battery a little bit and take advantage of the space. We can also grow the trackpad and we can still have great MacBook Air battery life.

Kate: There's definitely thermal control loops and software optimizations that we use.

The workloads for a typical MacBook Air owner are fairly bursty, meaning they may do something for a few minutes and then walk away from their computer and either have a background process running that's pretty light or just doing nothing at all. And so we can go in and tweak the levers in the silicon and software to be able to take advantage of these gaps in time and really take the power down to the most minimal level.

We also know when you're watching video, as an example. It’s a thing that many people do all the time and we optimize the silicon to be super efficient, either encoding or decoding those video streams. So it's such a great advantage for us to be working very closely with our silicon and software partners to be able to take advantage of that full top-to-bottom architecture of the computer.

Laura: First and foremost, the MacBook Air is a thin and light product that is very portable. So we began by staying very true to its value proposition to the user. And I think, with Apple silicon, we made giant leaps in terms of the performance and capabilities that an Air can have — amazingly — in a fanless design that operates quietly. And so when we talk about some of the performance gains, like with this new 15-inch Air being 12 times faster than our previous fastest, Intel-based MacBook, it is really remarkable.

But I also think users are doing more. You have so many people casually editing and uploading videos to their Instagram. You have more performance and more capability and users expect that. So i feel like Air has grown and then some in terms of what it allows the user to do with it. And at the same time, we've also taken MacBook Pro to the next level in terms of performance so it has new capabilities at the very high end of what creatives and professionals are doing with the device. So I think there's great separation there, and the MacBook Air now — similar to MacBook Pro — has a great choice in terms of display size for users to choose between.

Laura: We view the MacBook Air as a family, so I think having that familiarity when you're looking at the MacBook Air, you're really choosing between display size. And so we wanted to keep that consistent. We think the port selection is very complimentary to the thin and light design of the product

We also include the 35-watt dual port adapter on the 15-inch. We find a lot of people are using a port for charging one of their other Apple devices. And so the idea with that dual-port adapter is now you’re charging your MacBook Air and your iPhone or your iPad off of that, which really frees up a port. So that is an added benefit to the 15-inch. We do include the 35 watt, dual-port adapter on the higher end, 13-inch configuration, but it’s across the line on the 15-inch as standard.

Kate: We're always looking at other (options). We have a great materials team that helps us across the board and certainly when we went to recycled aluminum a couple generations ago they were huge partners for us in developing that particular alloy. In terms of the components, CNC aluminum gives us a lot of freedom to be able to make the features that we want quickly. Things like those undercuts for the ports in the enclosure really can only be done when we start with a block of machined aluminum and machine away.

The other thing is thermally we can take advantage. The aluminum conductivity is slightly better than magnesium alloys. Aluminum alloy is not massively better, but it's better enough in order to achieve what we want to in these products. And then there’s durability. The material aluminum is a little bit better. We work with the alloys team to design higher strength alloys, and we can take advantage of that, which supports going to these 11.5 millimeter-type enclosures.

Last but not least, the cosmetic finishes that we want are not possible to achieve in other materials.

It's a lot more difficult of an engineering challenge than most people might appreciate. Picking up this system by the corner and just holding the product, we make sure that it's stiff and durable and really presents that level of Apple quality that everybody comes to expect from us. We don't even want people to consider that. We want to do everything that we can to make this experience great.