Hardware and software
Much of the hardware and software used for HTL's measurements I have purpose-built and purpose-written (there's a complete listing in the Test details section). But two key items – the components of the artificial ear (manufactured by GRAS Sound & Vibration A/S) and the impulse response measurement software (ARTA) – I bought commercially. The links below will take you to their respective websites.
GRAS Sound & Vibration A/S