[sts9fan]

I currently have a sub sitting on a suspended wood floor and it needs
isolation bad. What are my options?  Giant slab of granite? Spikes and constrained layer?  No retail products please.

[mcgsxr]

For next to $5.00 you could try a lightly inflated bicycle inner tube - I have used them in conjuction with stone slabs under components in a rack with good effect, but never a sub.  Worth the effort to explore I would think.

[sts9fan]

Interesting.  I could try that.

[JohnR]

Is it downfiring?

[bigjppop]

They sell these tough foam/rubber mats at many of the home improvement places that you put under your washing machine to prevent it from vibrating; I've got one under my down firing sub and it seems to do the trick. Very cheap to try.

[satfrat]

I built a 27" sub stand for my Force XL using a (now discontinued) 24" Real Traps Soffit which was really nothing more than a cardboard box with fiberglass inside. From Timbernation, I had 2" thick oak platforms made for each end and four 2" oak corner supports with a 1" cutout to fit the box side corners. The top/bottom of the cardboard box had a 1.5" recessed cap so I filled the gap with hard density 3" memory foam. I then glued the whole thing together, thinking maybe the compressed memory foam on each end would help obsorb some of the vibration energy from the downfiring sub. I have 1.5" AudioPoints under the ACI sub and larger 2" Audiopoints under the stand itself. I have really old hardwood floors on a really sad cellar so I really needed as much isolation as I could get. Result was a much tighter bass than I had ever achieved with other methods such as cones alone, rubber/cork squares, slate platform and cork square/oak platform combo. I alsomass load the Force XL with a 2" platform of Lake Champlain black marble (full of nice shell crustations that pop when polished). 
 
Cheers,
Robin

[sts9fan]

Its not down firing but when I moved it out of the corner it is shaking the floor.  Right now it is on nothing, just sitting on the floor so anything will be an improvement I think.  Thanks fo the ideas guys. 

[richidoo]

If the sub is above a basement or crawlspace you can brace the floor with a post or column below the sub's location. Mass will have minimal effect at sub frequencies. Suspension/damping is the next best, but you may lose some transient accuracy / impact if spring is too loose like inner tube, but it will isolate well.

I'd like to try these, but they are not shipped to US, have to ask a friend in Europe to help.
http://www.sonicdesign.se/sdfeet.html

Unrelated to vibration but still a big improvement in clarity (which I assume is why you want isolation?) is to raise the sub up off the floor on a speaker stand.
Rich

[poseidonsvoice]

You could build a subwoofer isolation pad like Elemental does. These pics should help:

http://www.edesignaudio.com/index.php?cPath=2_126

Anand.

[rollo]

    Well on the cheap good ol hockey pucks. If you want to buy one check out Aurelex.


charl;es

[Big Red Machine]

I used a maple 3 inch cutting board from Dawn's with 2 inch spikes installed with threaded inserts.  Bought a board the exact size as the sub.

[stereocilia]

Like Rich says.  Space permitting, I would guess the basement floor jack idea would be far superior to anything else.

[rollo]

If the sub is above a basement or crawlspace you can brace the floor with a post or column below the sub's location. Mass will have minimal effect at sub frequencies. Suspension/damping is the next best, but you may lose some transient accuracy / impact if spring is too loose like inner tube, but it will isolate well.

I'd like to try these, but they are not shipped to US, have to ask a friend in Europe to help.
http://www.sonicdesign.se/sdfeet.html

Unrelated to vibration but still a big improvement in clarity (which I assume is why you want isolation?) is to raise the sub up off the floor on a speaker stand.
Rich

  Correctamundo. Our sub is 22% of the floor to clg. height. To the centerline of the woofer. Using an Aurelex pad on top of 3/4" painted MDF which sits on cardboard tubes 1/2" th.
  To tighten up the floor use of jacks or Lolly columns as Rich suggested. Use a plank between jacks to spread the affect.


charles