Just got my new HR21. I put it on a wooden shelf in an oak bookcase I installed next to my TV in the basement. One thing I didn't anticipate was how much it actually vibrates, which causes a low hum. The wood almost acts as a speaker cabinet for it. I was thinking about getting a glass cutting board to put underneath it between it and the wood shelf to try and deaden the vibration. I have an HR20 upstairs on a glass shelf in my TV stand, and have never heard this kind of thing from that one.

Has anyone else seen this? Any better ideas for deadening the vibes and subsequent hum?

Just got my new HR21. I put it on a wooden shelf in an oak bookcase I installed next to my TV in the basement. One thing I didn't anticipate was how much it actually vibrates, which causes a low hum. The wood almost acts as a speaker cabinet for it. I was thinking about getting a glass cutting board to put underneath it between it and the wood shelf to try and deaden the vibration. I have an HR20 upstairs on a glass shelf in my TV stand, and have never heard this kind of thing from that one.

Has anyone else seen this? Any better ideas for deadening the vibes and subsequent hum?
Get some of that rubber shelf/drawer liner material that comes on a roll and lay that under the unit. Either that, or get a stronger shelf.

Maybe some cork feet?

The rubber shelf liner seemed like the perfect idea. I got some and tried. Still humming. Amazing. Thought that would do it. I'll give the cork a try tonight. I'm starting to think about trying some of that eggshell foam they use in recording studios. I'm also going to take a look and see if there may be a ground loop present causing the humming.

Why should it vibrate?? Doesn't sound right to me. You shouldn't have to do any modifications for it to sit on a shelf. I would ask for a replacement.

Good point. I agree. It's an oscillating hum, not too loud, but noticeable if you mute the sound. It kind of sound like a fridge, but not that loud. If I pick it up, it's imperceptible. Also, if I pressed down on it a little, the hum went away. Good times.