Skylan speakers stands-how much sand?

Try taking some of the sand out. It sounds like you might have them a tad over-damped. Experiment with the 75% filled as previously mentioned. Also, you definitely need spikes or some type of footer to couple the stands to the floor. If using spikes, you'll need special pads for the spikes so you don't ruin the wood floor. You might also try some large Isonode footers or the Herbie's big dots under the speakers. There are a lot of threads on this subject, so you could do a search for more suggestions. Have you asked the Skylan dealer what they recommend? As I recall, wood floors, depending on if they are laid over a concrete base or are suspended, require different set-ups of the speaker stands. here's an older thread you might find of interest:

http://db.audioasylum.com/cgi/m.mpl?forum=tweaks&n=62576&highlight=sand+in+speaker+stands

And another:

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1156645142&openflup&2&4#2

Sherod:

Thank you very much. Those threads are very helpful. The stands came with flat metal feet, about .5 inch in diameter. I think that I will get the Isonode footers and the big dots.

Thank you, everyone.

That did the trick!

I placed Herbie's small Fat Dots under the speakers (Spendor S3/5), Herbie's self-adhesive grungebusters on the Skylan speaker stands' .5" flat metal feet, and Herbie's self-adhesive grungebuster Extra-Thick Minidots under the audio rack's spikes' floor disks. (I used the self-adhesive grungebusters on the feet because I need to move the speakers when I am not listening to them to prevent my young children from knocking them over.)

The Fat Dots substantially reduced the vibration in the stands. I assume that the grungebusters on the speaker stands' feet also reduced vibration in the floor.

The low end is even tighter than when I loaded the stands with sand, and the mid-range and high end are back.

Excellent! Thank you, thank you, thank you!

Good going! I'm glad things worked out for you. Enjoy the music.

Am I missing something here? Isnt the whole point of the sand to make the stand not move at all? The object is to make the speaker perfectly still, so that the drivers move more acurately. I highly doubt filling a stand with sand is going to take away anything. Its only going to improve. Speaker manufactures have said for years, adding weight to floorstanding speakers even makes a better improvement. I think your ears are without a doubt playing tricks on you. Maybe it is something else in your system you changed, even a setting in the prepro if you are using one?