At first I was leery - but then convinced. These absorbers decouple with me a loud rumbling Festplattenreceiver and media player with integrated hard drive. The disks had previously transferred their drive noise on the furniture. Simply the absorber placed under and now is just a really soft whirring sound. Next I have my 5.1 speakers - conditioning decoupled so. Just the right Heavy Fel - subwoofer are now his bass no longer depend on the wooden floor. In my view, a strong buy recommendation.