@brombo
If you are still looking, I can recommend these products -- good science/physics behind the [isolation] design --
Quote:
Norman Varney is the Principal Consultant for A/V RoomService, Ltd. established in 2001. During AVRS, Norman was Acoustical Product Development Manager for Kinetics Noise Control,
and prior to AVRS, was with Owens Corning at the Science & Technology Center where he was a Senior Engineer with the Acoustic Systems Business as the Acoustic Design Center Lead.
He has spent a considerable amount of time testing in anechoic chambers, reverberation chambers, and acoustic labs in general.
https://avroomservice.com/