Metal, aluminum, or wood for a rack ?

Wood is out . Ive found metal with a 50/50 fill mix of sand and lead work well . I'm in the heavy and ridged camp , although many are using the less mass method . Any solid ridged stand will be a improvement .

what is the purpose of a rack ?

i see two .

1) a way to access components (i place them on the floor)

2) access the components and avoid intruding resonances at certain frequencies.

so the question is if materials resonate at a certain frequency, which one do you prefer.

i would think achieving a resonant frequency as low as possible is the way to go.

thus, i would opt for wood. you can always use anti-resonant devices under the components.

I just glued and screwed my two 3/4 in Birch plywood shelves together to make 1 1/2 in shelves and rapped on them with my knuckles and it was very impressive.

It sounded like you hit a concrete block.

No reverberation or resonance to speak of.
It's much better that the 1/2in MDF I'm using right now.

I'm also using Maple butcher blocks with cones between the shelves and the amp and CD player.

It's comming along just great.
When I'm done I'll put new photo's in my virtual system and update it.
Have a great day.

Oh.... +1 on the wood resonance.

I have finnished my rack. I'm so proud. It turned out beautiful. Very solid.
Click the systems link to check it out.

Z:

Nice rack. I wish I took woodshop in high school. I got stuck with two semesters of printshop due to scheduling problems. Maybe in my golden years I'll take it up.