recommendation for turntable vibration damping


hi!
i recently moved into a new home and just completed a project to install insulation under the floor (in the crawlspace). this was done to save on heating costs, but i figured it would also help to dampen vibration from the floor. the floors themselves are fairly cheap with thin carpet over them. (we are likely to install hardwood floors in about a year or so.)

anyway, after the insulation project was complete, i noticed that if i tapped my foot (as in moderate footstep), i could see my turntable shake. i'm wondering what steps i could take to reduce this vibration.

here are some relevant details:
>> VPI Aries on a Bright Star Air Mass 19, sitting atop a...
>> Finite Elemente "Spider" rack built up about 24" with a preamplifier, CD player, and VPI SDS also on it/weighing it down.

the rack is modular (which has served me well during a few moves) and is lightweight.

i'm wondering what my options are for reducing vibration -- i don't think i can afford a big/heavy rack right now.

is something like a bright star 'big rock' advisable? i would imagine loading it down with sand would really weigh down the rack and, presumably, dampen vibration. (they're not cheap, though...especially for the size i need for an original aries. i don't have an outboard flywheel, but i may get one one day.)

i'm open to any thoughts.

thank you in advance.
ebalog

Showing 7 responses by valve_and_vinyl

Target wall mounted turntable shelves are simply the way to go.

Damping your turntable's chassis is so trendy but few realize it can also suck the soul out of it. Try the wall mounted shelf first; It's cheap and EXTREMELY effective!!
I just thought of something-

Why not consider buying TWO target shelves? If you did it right- you could space two shelves apart so that your TT was suspended in the middle gap (each pair of feet resting on 1 shelf). That way you'd have even better isolation, underneath access (for suspension adjustments), and room on either side for a dedicated phono pre and/or misc cleaning and maint gear.

I might do this myself!
Hi Ebalog,

How's it coming along??

I just wanted to say: Don't completely dismiss the wall mounting option- it's superior.

Wall mounting your turntable is one of the best ways to isolate it. Even when vibration isn't as obvious (as it is in your case), wall mounting is still a choice method. You should brace the floors anyway- that will help no matter what you do with your TT. (my 2 cents).

If Target doesn't have the size you are looking for- try Apollo or Rega (Needledoctor carries both). A google search will turn up a lot of leads as there are several manufacturers making them.

Even a simple DIY wooden shelf will do wonders for your turntable. If you are mechanically inclined enough to tackle bracing and securing your floor joists- you can obviously build a high quality wall shelf that will not only look great- but will reap a LOT of performance increase for under $50 & a couple of hours' worth of effort. Look at the analogdept.com site and check out the DIY shleves for inspiration.

best of luck with your audio adventures and let us know how it all works out.

Take care.
You'll really be happy with a wall mounted turntable. I used to walk with such care- now I can do whatever. Before I had a wall mount, I wouldn't want to get up during playback- not even to answer a phone/door for fear that I would make the needle jump! I felt like once to record had started- I was a prisoner. That's not to mention my active 3yr old who loves to jump around when the music is on. I was constantly trying to keep her from dancing, and I though 'What's wrong with this picture!? She loves music; Just like her dad.' Now it's nice to watch her do her dance routines without worry. :)

The overall fidelity was improved, too. Bass got tighter- highs more silky...
I told ya!

..wall mounted shelves are the way to go. I'm so glad you are reaping your just rewards. ;)

about the floor-

Block it first!! Whatever you choose to do for a pier, put a healthy amount of cross-blocking in between the joists first (say...every 2-3'. staggered) and I bet that makes a huge difference all by itself. Be sure to use the same dimensional lumber your joists are and be sure the wood is pressure treated.

I would do this: In an area where you have pre-selected to brace with a pier- drop a plumb line down into the soil and excavate a hole with a foxhole shovel that is below the frost line (whatever it is in your area) by at least a few inches and approx 2' by 2' square. Drop a large 18" by 18" patio stone of compressed concrete in the bottom of the hole and level it. Cut a piece of 6X6 PT lumber post that is exactly as long as the top of the stone to the top of your joist and then cut a notch in the post to accomodate your joist. Carefully tap the post in place and drill a 3/8" hole horizintally through the post and joist join and install a galvanized cairrage nut/bolt with fender washers. Double check for plumb and then tighten the nut. Back fill the hole and tamp it hard. 1 of these piers in the right location (after you have installed plenty of blocking) will make your floor rock solid. You can always add as many as you like- but 1 good one should be PLENTY for a room your size.
Hi,

Lumber isn't cheap either. I just put in a new deck 12' X 12' and even though that's pretty small- it set me back nearly $2K. Ouch.

Yep- blockling is putting in a piece between the joists (or studs).

The only problem I see with your joist jack method is that you are at the mercy of nature, in that you will probably need to re-adjust it often because of heave and expansion/contraction. A jack like that indoors remains fairly stable; When it's exposed to temperature outdoors....

When a builder puts in a bathtub, stairwell, or anything else that requires either a cut-out in the joists and/or extra bracing, the common method is to add blocking. It may not seem like it would add a significant measure of support but it certainly does. When the joists are allowed to flex independently of each other- they do. When held to the rigidity of its neighbors (other joists)- they don't. Pretty simple.

Use whatever type of column you wish, but I would still block the joists to the hilt. If you recently added insulation, you could just make a header or horizontal beam to distribute the load of your column of choice. This could serve to replace the blocking (sorta). Make sure you toenail the beam in an X wherever it meets a joist though. I'd double up (sister) a 2X6 (at least) for your header/beam. 2X8 would be better. I'd put two columns (per beam) if doing this method.



Considering that the work you are doing will not be "load bearing" per se- I think ALL options (suggested thusfar) are OK.

True, a crawlspace is not as extreme an environment as the open air. Your jack will prob be fine.

I think you'll be very surprised at just how effective a mere fraction of what you are proposing will be. Hard to imagine- but bracing just two or three joists alone will be a huge inprovement. Now- factor in what you are contemplating and multiply it by 200%. Your floor won't move by any measurable degree. Audio speaking of course...