The best way to isolate my subs from the floor?

Check out the Sub Stand at http://www.acousticsciences.com/products.htm A little pricey, but…

I too live in an old house with hardwood floors. I have had great results with my large Dynaudio Temptation speakers sitting on 1" thick granite slabs with 3 Aurios(ball bearing) between the granite slabs and the speakers. Really tightens up the bass and keeps most of that low frequency from transferring into the floor.
Cheers,
Gregg

You might want to try bracing the floor from underneath using some 4 x 4's and / or some hydraulic bottle jacks. You can place the bottle jacks on top of the 4 x 4's to get them up near the floor and then adjust the bottle jacks for the amount of tension you want on the floor. If the floor is poorly suspended and "sagging" all over the place, using another section of wood where the bottle jack and the floor joist meets will help spread the tension out. This will support a larger portion of the floor using fewer jacks, making it a far more useable approach. Then again, this assumes that you can get beneath the floor ( via a basement, etc... ) and that your system is located on the first floor. If you are in an apartment, condo or up on the second floor, this is probably not going to work for practical reasons.

I will only add that altering the distance that the driver is above the surface below it will change the tuning and output characteristics of the sub's. All down-firing drivers are tuned with a given space between them and the support structure beneath them taken into account. As such, be careful with what you use, as it could end up altering performance enough to make you not want to use the subs at all. Sean
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The Sistrum SP-004 is a wonderful sub stand. $185. Excellent. Will couple your baby right to mother earth. You can see a picture on their website: audiopoints.com peace, warren

Try something with bicycle innertubes. I used these wrapped around some home-made Sonotube-based subs, with good effect. I have 16" subs, put 3 inner tubes around it, lightly inflated them - worked quite well. Try a platform of MDF with sub on top and innertube flat underneath it.

-Ed

I have seen Vibrapods recommended several times for use under speakers. They are about $6.00 each and are available from several sources. They would be the least expensive option posted so far, won't harm anything, can be easily removed if you don't like the sound, and can also be used under other components.

I have three 1" superballs that are cut in half. Three of the halves are on the floor supporting a piece of MDF. The other three have are between the MDF and the sub. This "double isolation" works great.

Be very careful as you may get what you ask for. Until a year ago I used two pairs of Entec lf40's which had very extended low frequency response. After hearing a friend's system with the same speakers who had put spikes underneathe them, I tried doing the same on my very solid wood floor. This was an unmitigated disaster. The bass seemed to disappear. In speaking with my friend, I learned that his floor was carpeting over a concrete slab.

After some reading, I discovered that wood floors are very similar to drum heads with a very complex pattern of resonances which varies depending on the particular place on the floor that you site something. Concrete slabs apparently flex less and are more predictable.

The moral is not to try anything which you cannot return if it does not work.

I use 3 inch dia solid aluminum legs. I then put 1" spike under each 6 inches tall cylinder. 1/2 inch Rubber feet between the speakers and each Al legs. Depends on what's your dimension. I used total of 60% surface area of bottom of the speaker as the total size I need for the alumium.

You can go crazy with what works for you....
You just need to know how much control and isolation you need.

I agree with many of the suggestions made above. In my old wooden house I used floor jacks (my floor was shaky) mass loading (chimney bocks) got sub off floor with racquet balls sitting in PVC cutoffs). In addition, I used two large homemade tube traps (try cardboard boxes first). The result was much better bass control. I also stuffed straws in my speaker ports. Each thing I did required listening to the results, but all were cheap-except for the jacks- and easy to reverse.

I have a similar problem. I like the superball experiment.

But racquet balls? Geez. Who needs a flat tire in the middle of a movie?

I use Aurios isolation bearings under my Dunlavy IVa's. It's amazing at how quite (non vibrating) the floor and speaker cabinet get. I know it sounds like an odd idea to put speakers on bearings, but it actually makes sense if you tjink about it. The bearing is in a cup shaped base so in order for the speaker to move it must move the bearing up hill, against gravity. It can not do this so the speaker is still, the ball vibrates (I guess) in place and isolates the floor from the speaker and visa versa. Imaging is better, my base has much better definition. Try to find a cheap used set (three bearings per speaker) or a local dealer who will let you try them at home.