Ｓｋｅｅｗｉｆｆ#PatchTheStudioCat would like to take this opportunity to thank loudspeaker manufacturer Focal, for building a 'Patch Bay' into the top of their studio monitors.
Others may refer to it as a 'passive radiator'' or 'sympathy woofer' but Patch knows best: It was clearly designed with cat bass-massage in mind. 
Jason Newton