[RE-wrenches] Magnum buzz box

[Drake]

I installed a Magnum 4448 PAE today, and it makes an unacceptable 
amount of noise. The backplate is mounted with Tapcons to a concrete 
block wall. Does anyone have any tips for quieting this thing down? 
Would a rubber membrane, mounted behind the backplate help. Other 
Magnum inverters I've installed are a bit noisy, but this one is over the top.

Thanks,

Drake