Noise-cancelling headphones are great for travelling and using in noisy public environments, but they’re not terribly useful when you want to watch a movie in your home theater. There, things like Sony PS3s, NAS drives, satellite receivers, and any other device with a built-in cooling fan that may happen to be sitting in your equipment rack – including, sometimes, cooling fans for the rack, itself – can be irritating sources of background noise that take away from the enjoyment of whatever it is you’re watching. Silentium’s AcoustiRACK ACTIVE (ARA) combines passive noise reduction with the company’s unique and highly effective active noise cancellation technology to achieve pretty incredible noise reduction levels of up to 30 dB. The ARA is specifically designed for data centers with racks of servers and other noisy, heat-producing components and has the ability to dissipate up to 8 KW of heat while also protecting the gear from dust. While I was at the Silentium booth, the folks there demonstrated how well their active noise cancellation technology is by displaying two wooden cabinets with identical exhaust fans built into the top. The first cabinet contained the fan and nothing else – and was appropriately noisy. The second cabinet included Silentium’s circuitry and hardware within the cabinet – and it was very noticeable how much more quiet the fan was compared to the untreated display cabinet. Silentium’s ARA racks (in 15U and 33U sizes) cost multiple thousands of dollars each, but the Silentium representative said the technology could potentially be adapted to home AV racks, as well.