Inside Apple’s HomePod Audio Lab

Jim Dalrymple:

The noise and vibration lab was set up years ago to work on unwanted noise from Macs. At the time, this lab was very focused on fan and hard drive noise, but over the years it has expanded into electronic noise as well.

“Reducing fan and hard drive noise” is such a fun origin story for a lab that is more relevant to the company (and seemingly better-funded — see below for the insane specs for their newer anechoic chambers, which Apple claims were designed and built just for HomePod) today than ever. This is the same lab that tests and helps design the ever-improving speakers in iPhones and iPads — neither of which product has ever had a fan or hard drive.

The last chamber I saw was designed to listen specifically for electronic noise. For example, you don’t want HomePod to make any kind of noise when it’s plugged in, but not in use. If it was sitting on your night table, you wouldn’t want a hum or buzz coming from it.

Geaves said that the extent you have to isolate this chamber is even more important because you are listening for really small sounds.

The chamber itself sits on 28 tons of concrete. The panels are one foot thick which is another 27 tons of material, and there are 80 isolating mounts between the actual chamber and the concrete slab it sits on.

The chamber is designed to be -2 dBA, which is lower than the threshold of human hearing. This basically provides complete silence.

I was on the same tour of this lab that Dalrymple was, and at this moment Geaves had us remain silent for 10 seconds or so, just to appreciate what true silence sounds like. It was… unnerving.

Monday, 12 February 2018