A vacuum cleaner connected to a long hose that leads into the recording room, so you don’t hear the machine - that’s how this library was created.
It contains sounds from sucking in different materials, dynamic unreal winds & unbearable squeaks from the hose. Furthermore it includes sounds from “inside” the hose/pipe: Close-miked pass-bys of small objects, driven by the wind.
The recorded frequency content goes up to 100kHz, using a combination of microphones like the Sennheiser MKH 8040 and the Sanken CO-100K. Part of the sound files are already pitched down, so at the delivered 24bit - 96kHz resolution you can pitch them even further down without trimming the full audible frequency spectrum.
Read the Making Of Blog Post