After reading some of the early reports of AirPods Max users noticing condensation inside the earcups under the memory foam ear cushions, I have been keeping an eye on mine. After two recent two hour or longer sessions using them, I can confirm that I have found small amounts of condensation inside of mine, as well. This definitely isn’t a fictitious issue.
This problem is interesting to me because I work in Commercial and Industrial HVAC, Energy Management and Monitoring and Systems Integration. The engine that’s driving this problem is right in my wheelhouse, which is a big reason why I decided to write about it.
For all of the positive aspects of the AirPods Max, I think we have finally found its first gen stumbling block. Let’s face it. Many new products, even those from Apple, have them. The more novel the design, the more likely you are to find a flaw like this one.
I love the look and feel of the AirPods Max aluminum design, but this condensation issue is a direct result of Apple’s choice of materials, both for the earcups and the pads that cover the insides of them. Let’s get into why that’s the case.
If you think about the science of how condensation occurs, then it makes perfect sense why this is happening. And let me give you a hint- it has nothing to do with your ears sweating. I found myself shaking my head earlier this evening while listening to Erfon Elijah rant about this on Cult of Mac’s most recent episode of the Cultcast. Google is your friend, people. Or in your case since you are reading this article, I am.
So why is this happening? It’s actually pretty simple and straightforward and it all starts with one simple premise- heat is energy and can’t be changed or destroyed. But it can be moved. The exchange of heat is the engine behind all forms of heating, air conditioning and refrigeration. It’s a shell game using effective conductors to transfer heat energy from Point A to Point B, depending on the desired result.
So what does this have to do with condensation inside of the AirPods Max? Memory foam, like the kind Apple uses for their ear cushions, is quite comfortable, but it can also trap heat. Mattress companies have invested a lot of money learning how to mitigate the potential for people to get hot while sleeping on this material, and they are just dealing with gravity pulling a person down onto the foam, which tends to give and form around the body. To assist with Noise Cancellation, the AirPods Max headband holds the ear cushions tight to the wearer’s ears, increasing the potential for trapping body heat. I definitely notice that my ears are quite warm after an hour or more wearing my Max.
If the AirPods Max’s earcups were made out of plastic, this wouldn’t be an issue because plastic isn’t an effective thermal conductor. That’s actually a major feature of the material for many applications. Unfortunately, aluminum happens to be an excellent thermal conductor that can also store a high amount of heat energy.
What does that mean? High thermal conductivity means that aluminum can absorb heat well. The high heat capacity means that this metal can also store heat effectively. Have you ever touched the outside of your AirPods Max (or any other aluminum device) and noticed that it always feels cold? Strictly looking at the surface temp, it isn’t actually as cold as it feels. What you feel is the effect of you exchanging your body’s heat to the metal.
I digress. Back to the subject at hand. Unless the AirPods Max’s earcups are artificially warmed or warmed by high ambient temperatures, they may not be as cold as your fingers say, but they will be cooler than the heat generated by a wearer’s ears and the Max’s memory foam ear cushions. Because the aluminum is an effective conductor, that heat will then exchange to the metal, as well as the air inside of the headphones.
When that happens, the rest is similar to what you see with a cold aluminum soda can in the right conditions. The exchange of ambient heat to the metal of the can cause the surface to reach dewpoint, which is the temperature at which condensation forms. So that condensation is a byproduct of the heat transfer that’s occurring. If that same aluminum can and the liquid inside of it were equal to the ambient temperature, it would be as dry as a bone. Why? There’s little to no heat exchange going on since the temperatures are roughly equal, so there’s nothing to moving the surface of the can towards dewpoint.
In the case of the AirPods Max, we are doing the same thing from the opposite direction. The insides of the earcups are usually going to be cooler than the heat generated by the ear cushions when they are worn. This exchange of heat brings the metal to dewpoint, which causes condensation inside of the earcups. And just as with a Coke can at room temperature, a set of AirPods Max sitting unworn in their flimsy Smart Case won’t have any issues because there’s little to no exchange of heat going on if things are equal.
I have to say that I’m somewhat disappointed in Apple’s product team over this design issue. How did a room full of product designers and engineers miss the potential for this to be a problem? How did this go undiscovered in testing, where it could have been addressed before release? I’m not showing off any cutting edge scientific knowledge here. This is basic middle school physical science I’m rehashing.
So what can Apple do about this? There are a few things. In the short term, they need to work on the design of the memory foam ear cushions. Even if they stick with the same basic material type, they likely need to tweak the formula to reduce heat generation and promote ventilation. Third party vendors should also be able to step in and offer replacements using different materials that don’t generate as much heat. Alternative ear cushions could mitigate the problem for existing owners while Apple tweaks the design of the next gen Max.
Ventilation is a big key, overall. A little additional ambient airflow through the headphones could help to dissipate heat away from the metal and equalize the interior temperature. However, it is very possible that this would be detrimental to the sound quality, which would kind of defeat the purpose of the product. As far as ventilation is concerned, altering the cushions is probably the limit of how far Apple can go.
If that’s not enough, then Apple will have to look at the metal they are using for the AirPods Max earcups. Now we are getting into the black art of metallurgy, where different alloys can be customized at the molecular level to heighten or lessen certain properties. In this case, Apple would want to develop an aluminum alloy that is less thermally conductive. That may not prevent the problem of condensation, but it would make it less likely. This in combination with other tweaks should solve the problem in most cases.
I’m not sure with this AirPods Max design misstep qualifies as a true Apple “gate.” However, it is significant because of the price of these headphones.I know I expect a lot from Apple and I don’t know why anyone would be good with giving them a pass on this. They need to be accountable and warranty any AirPods Max that may be damaged by internal condensation, as well as coming up with short and long-term fixes for the issue.
Oh, and maybe Apple’s cutting edge engineers need to take a step back and spend a little more time considering basic scientific principles and how they may affect their designs.