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In the Forum: Audio Discussions
In the Thread: Mastodont DIY Rack: Wall Mount?

Post Subject: Spike pickupPosted by N-set on: 12/2/2013

Paul, I hear you clearly re wall mount. Well...I have chosen the hard way an occasion to have one, +/- universal solution I could "copy&paste"
if I change location. Go through that hell and have it done once and forever.
I even ask my daughter to put this mastodont on my grave when I die. Not so much as a symbol of my biggest
achievement but rather something that shortened my life Smile

I'm not sure I was clear with the spikes. I see them on 100% of all "high-end" racks (but never-ever on e.g. optical tables, where nano-vibrations can ruin everything) and I've "smartly" decided to follow the crowd,
semi-backed up by the fact that they are also used as a simple antivibration mounts in industry. What escaped me is that
I've approched the subject from the ass: in the case of vibrating machinery, what is on the mounts is vibrating and we want
to decouple that from the floor. And there the spikes can work as they provide some angular and torsional freedome of motion
Here of course is to the opposite: floor is vibrating and we want to decouple the rack form the floor.
By achievieng super high pressure the spikes are tightly coupled to the floor and I believe happily transmitt everything.
A nonsense "solution" in other words. That's why I'd like to try a wide feet with a big area, low pressure contact to see how they behave,
if there is any difference at all. The felt idea sounds ok, but felt gets compressed and has to be exchanged from time to time
and I dont want to do that with a 300-400kg mastodont.

As for the bladders that break the vibration path, let me repeat: I don't want the support rack to add them additional work by its
own resonances, magnifying the floor modes. I start to believe that a better strategy than mine would have been a lightweight, rigid frame, topped with baldders and a high mass, not a high mass frame. Well, I can always get rid of all the profile filling and will end up probably with a pretty rigid
frame, given the sizes of my profiles.

Rowuk, of course I do what you describe!! This is how I learn e.g. the vibrational spectrum of my neighbour's waching machine. But I wanted
a cheap solution to check every frame member. For 10Eu I don't expect much, but hope it to have some output below 20Hz. I don't need
the exact amplitudes of the modes, only a very rough guide: the lowest present modes must be the fundamental and should be attacked first.

Cheers,
N-set

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