Okay, so you want to turn the universe’s afterglow into something you can hear. First, you’ll need a microphone that can sit in the 3 K thermal bath of space – basically a cryogenic, superconducting sensor like a Transition Edge Sensor bolometer, not your ordinary condenser mic. Then you couple that to a SQUID amplifier to pull out the minuscule voltage changes. Keep the whole thing shielded from all stray RF, and yes, you’ll need a Faraday cage that’s also a cryogenic vacuum chamber. Once you’ve got that, you’ll have to convert the 160 GHz spectral line into audio – probably by mixing it down with a heterodyne system and then sending the beat note into a low‑noise preamp. Finally, you’ll log the waveform, run it through a digital signal processor that applies a 1–3 kHz bandpass (because that’s where human hearing sits) and you’ll have the cosmic background’s “voice.” It’s a lot of hardware, a lot of calibration, and a whole lot of patience, but hey, if you want to hear the universe chill out after the Big Bang, it’s the only way.