I agree. The vast majority of ANC problems with APP Gen 1 and 2 stem from clogged vents and defective sensitive MEMS mics.
It took Apple 1 year to create a service program for APP Gen 1, because the return rate had been through the roof, with many customers swapping them more than 7-8 times. Apple prevented a class action lawsuit this way.
They tried to reduce the problem by recessing the vents. Originally, the vents were flush with the AirPod’s surface. By recessing the vents, they tried to give users a bit of “buffer room”, so that ear wax, dust, sweat, dead skin cells etc wouldn’t be pressed through the vent grid with force when making contact with the ear. This didn’t fix the fundamental problem. Depending on how you handle them, it merely delayed the issue.
Even with this high return rate, AirPods are one of the most profitable products at Apple, making them billions. Since the battery can’t be swapped out, it’s a money-printing machine when many people upgrade after max. 3 years.
Critical thinking isn’t everybody’s strong suit, especially on the internet. Thankfully, Apple introduced a function with APP Gen 1, the fit test, that helps to narrow the issue down. This isn’t a gimmick, it actually works. It plays a reference signal and listens to the output with its microphone. If the pressure is in the correct range, it passes the fit test. This is only the case when:
1. There is a good enough seal
2. The vents aren’t clogged up
3. The microphones aren’t damaged
If you passed the fit test initially or do with a new pair, but using your old tips, and now don’t, then you will experience a decline in ANC and bass performance.
If you pass the fit test and still feel that there is a drop in ANC / bass performance, then it is most likely just a placebo effect. You can sell people in the audio realm all sorts of snake oil and they think that it improves the sound, when it is scientifically impossible.
Examples:
- CD “demagnetizers”
- 2000$ cables
- CD scraping devices that scrape the outer edge of the plastic substrate layer
- USB “re-clocking” devices
Apple didn’t move the grid on APP Gen 2 due to design reasons or for fun. They moved it further away from the ear, in hope of preventing the accumulation of dirt in them.
Cleaning them with Blu Tack can help for a while, but also bears the risk of pushing fragments through the grid.
If you use alcohol to clean the vents, it will sip through into the AirPod, sooner or later destroying the very sensitive MEMS microphones. Water has enough surface tension to get stuck on the vent to a certain degree, but alcohol doesn’t, it goes right through.
Using compressed air will clear the vents for a while, but will ultimately damage the mics as well. It’s just a ****** design to begin with.
The best you can do is to clean them from the start with a microfiber cloth, several times per day. Don’t touch the vents, not even with the microfiber cloth. Swap the microfiber cloth or wash them regularly, because otherwise you just smear skin oil back onto them. Clean the tips with water and a tiny drop of soap, but detach them before you do. Then dry them thoroughly before re-attaching them.
Btw, other ANC headphones, like Sony’s popular XM series also have issues, but with moisture buildup. It’s so bad that it corrodes the screws inside. But even they have a gluey sticky tape inside the earpod, near the vent opening to trap dust and prevent it from getting stuck in the MEMs mic membrane. If this happens, the mic will create random noise, ruining the audio signal.
Many of these ANC headphones use arrays of them, meaning several microphones, inside, outside and for the purpose of figuring out the directionality of noise. The more mics are used, the higher the probability that at least 1 will fail over time. And 1 is all it takes, as they all provide a part of a signal into the same audio pipe - the signal that users then listen to.
So, tl;dr:
99.9%: It’s NOT the firmware.