Dealing with an unstable, vibrating wood floor...


Hi everyone, as some of you know, I've been substantially upgrading my hi-fi lately. Currently a CJ amp, just got a Michell Gyro SE, and a JJ 243 pre on the way. I'm admittedly a newbie to audiophilia. Now I need to worry about stablizing the equipment rack. Here's the deal.

I have my rig on a four-shelf rack, a welded steel Sanus on spikes with 3/4" MDF shelves. I live in a 130 year old bulding on the third floor. The hardwood floors have seen better days--some loose slats, and the floor is VERY loose and prone to vibration. I can't even walk across the floor without making the turntable bobble on its suspension a little--the floor flexes slightly under my feet and takes the rack with it. I really, really need to work on stabilizing the rack! I've found that vibration is a significant cause of poor sound from my vinyl rig--pops and ticks, lack of clarity and detail, etc. and forget using a subwoofer, the low frequency waves render my vinyl rig far, far worse than my ho-hum Marantz CD5000!

Some problems--I know I'd be better off with a wall shelf for the Gyro, but you'd be right to guess that my walls about as good as my floor. They can't hold a spice rack much less a shelf with a turntable sitting on it. So I'm stuck with the 'table on top of the rack. I also can't afford to get a Neuance shelf or some such.

I'm wondering if sheer mass would do the trick. Could I put the whole rack on top of, say, a couple inches thick cement flat, then level the rack on it? Or could I have a cement or sand-filled shelf in place of the standard 3/4" MDF shelf my Gyro currently sits on? My main problem is the whole rack is unstable, so that's another reason why I hesitate on a massive shelf for my 'table. Would it pay to put the whole rack on something solid, of great mass?

I don't have a ton of money to work with, but my current situation is unacceptable! If anyone could steer me in the right direction or give me some DIY tips, this newb would be very greatful!

P.S. I have scoured archives, and found some interesting points, but I haven't found a discussion of isolating the rack from a loose floor.
dirtyragamuffin
Very good answers above. My house is century-old wood box (3-inch thick planks all over) on shallow stone foundation, and every piece is connected to every other piece so that an upstairs door slams and the whole house trembles for a second. But wall shelf on outside wall, in my experience, works perfectly. Problem is siting the rest of the equipment!

Mass under rack may not tame seismic vibration from footfalls and door slams. I worked in a store with a low brick wall as a TT demo shelf. The whole wall oscillated at maybe 2 Hz if we danced, and sprung suspensions hated that.
Wall mounting your deck to a load bearing structural wall would be your best option.
Think of your upper story floor to be a diaphragm attached at the edges of the load bearing walls.When the floor is disturbed, there will be more vertical movement at the unsupported center of the floor and less at the supported edges near the wall.
Footfalls,etc will thus cause a floor mounted stand to sway/rock(lateral) as well as bounce (vertical).The taller the stand,the more exaggerated the swaying/rocking motion will be.
Any turntable (and particularly suspended designs like your Gyrodeck) will react quite negatively to any lateral movement.Tho obviously having no motion at all is better, your Michell's long travel suspension is designed to deal with vertically oriented movement/vibrations fairly effectively.
Increasing the mass will only change the rate of the floor's motion but will not do anything to stabilize the flooring & stand.In addition,the increased mass will store more energy in the floor, resulting in a longer duration for the energy to dissipate.
A wall mounted support should provide you with the least vertical and lateral movement as well as storing the smallest amount of vibrational energies as you'd only be supporting the mass of the turntable and shelf.
If wall mounting is unacceptable or a monetary concern, you could move your present rack very close to a load bearing wall and improvise a bracket to solidly affix the stand to the wall(attach it near the top of the rack), thus mimicking a majority of a wall support's benefits.
You could alternately place the turntable on a low stand as close as possible to the wall to minimise the swaying effect. The inexpensive IKEA Lack sidetable(~$15) makes a very good performing low mass, cost effective dedicated low stand option.

Good luck.
Best,

Ken
GreaterRanges/Neuance
Dirtyragamuffin, I didn't factor in the suspension of your TT. It probably would not be a good match with the Promethean Base.
If your walls aren't strong enough to hold a spice rack then you need to move.
Dirtyragamuffin:
Your situation is difficult indeed. Don't think you might be able to fix completely but you can "improve".
1-Do you have any place where the floor doesnt bobble that much? If you can find the betterplace you can decrease the ammount of problem to begin with. Move your rack there
2-You need to provide degrees of freedom i.e. movement to your rack as a whole shooting for horizontal movement (easy to implement via ballbearing etc) and in the vertical plane (more difficult via innertubes ) the idea is to have the larger mass the rack supported by means of a damping mechanism that will "lessen" the vibration effect.

3- If possible try to "link" loose slats by means of adhesive between adjacent moving seams.

Some thoughts to share. Your comments
Regards