2 Royalty-Free Audio Tracks for "Condo Noise"

Condo vibration and pulsing caused by gas furnace 55hz and unknown source 128hz.

Here's a low volume, low frequency noise recorded during an acoustic survey of a condominium to identify a sleep-disturbing noise. It is primarily a combination of 13, 18 and 23 hz (5 hz steps). Not audible on computer speakers, it should be listened to on closed back headphones or very good quality sound system.