My rig's 4 space rack is rattling pretty badly on certain. Rather than not play those notes, I'd really like to fix the rattles. Based on some searching I've done here, I bought Auralex isolators (Gramma and the foam ones that go under speakers). They arrived yesterday and helped, but didn't fix the rattles. I think the rattling may be coming from contact between pieces of equipment in the rack (almost a buzz on some pitches). I haven't taken the rack apart yet (tonight's project), because when I do, I'm thinking of putting something (?) between the tops/bottoms of the units to isolate them from each other. Any suggestions on what to use for this or how else to troubleshoot? What's in the rack: Furman power strip Eden Navigator Preamp Aphex 204 exciter This rack sits on a separate 2 space rack that holds a QSC 1602. I split the power amp off into its own rack because I take just the equipment rack to church for gigs there. Thanks in advance for any/all quick suggestions so I can buy what I need on the way home this evening.