I’ve done a good amount of research over the last week. Obviously the key design requirement for a rack is to have super low vibration at any point that is contacted by the equipment. I.e. the shelves. There’s a lot of junk on the internet about what makes a good rack, but from a more scientific perspective I think it comes down to the following factors:
- High Mass
- Some form of damping
- Unit stability
- A low structural resonant frequency
- Structural strength, yet at the same time achieving the above
- Level adjustable
To control vibration of the unit as a whole, the first 3 points apply. To control internal resonance, which is by far the most important aspect of reducing vibration, all first 5 points apply. Level adjustability is simply to help with CDs and LPs spin on a horizontal plane.
So I think I’ve come up with something like this:
- Minimalist design (since my skills in metalwork are limited)
- 65mm mild steel columns, sand filled do deaden vibrations. I believe steel is more resonant than aluminium, but thick extruded aluminium is hard to find and difficult to weld. It’s also more difficult to finish, although theoretically I could leave it unpainted. Unfortunately my confidence in welding limits my desire to use it.
- Thick MDF shelves (acoustically dead)
- Three feet design
- Vibration isolating adjustable feet (I’m able to get some from my dad, who works in precision manufacturing. They have feet for heavy machinery which are not only completely adjustable, vibration isolating and limiting, they can handle a huge amount of weight).
I’ve been thinking about how I was going to couple the shelves to the rack. The internet tells me to use spikes. They’re the most popular form of contact for any “high end” rack shelf. But I’m not really convinced that it’s a good idea. Ideally with a vibration reduction system you need not just high mass but good damping. If the shelf is much less resonant than the frame (which MDF definitely is), it’s much better to damp the coupling layer rather than fix it. You’d still want the frame to be as unresonant as possible, but it’s never going to be able to achieve the natural deadening properties of wood.
Anyway, the drawings are done. But I’m not going to post them here as my artwork skills are horrible. Going out to buy some materials now. Back later…