Last Friday, Apple held a press conference addressing antenna issues with eh iPhone 4. And at the same time, Apple unveiled its once-secret testing labs and invited 11 members of the media on a brief tour after the event.

The tour was led by Ruben Caballero with the purpose of showing that Apple takes the testing of wireless issues very seriously, and that suggestions that the company was simply sleeping on the job when it came time to test the iPhone 4 are misguided.

According to Macworld, Apple's wireless lab has 16 different anechoic chambers padded with foam shaped into pointy cones to stop all reflections, designed to create completely radio-neutral environments—at a cost Caballero estimated at $1.2 million per chamber.

Caballero would occasionally step into a chamber, leading in a few reporters, and the moment he entered the chamber his voice became nearly inaudible, due to most of his sound being absorbed by the foam on the chamber's walls. Even the handles of the heavy doors are made of Fiberglas, and the doors are lined with copper to ensure the entire room is a Faraday cage. The point of the chambers is to map the electromagnetic characteristics of a device by eliminating all other electromagnetic signals. The device to be tested gets placed in a chamber, and when the door is closed, it's cut off from the rest of the world.

Apple’s tests are conducted in a variety of settings in the company’s testing chambers, including positioning the device on styrofoam blocks, in human hands, and in the vicinity of realistic “phantom” mannequin body parts. At the end of the tour, Apple showed a CT scanner and a field-Validation van.