How to fill and some observations..
I have read a lot on acoustics and air columns, and I agree with you that "an empty air column in the stand will resonate.." My stands were only 1/3 filled..and 2/3 air cavity...not good physics.
So I found this here in the past notes:
".....Ideally your speaker stands should have no "sound" of their own. No sympathetic vibrations, no ringing, no resonances. Filling the stands definitely should attenuate any sounds from originating within the stands. Do a knuckle test, before and after. Knock on an unfilled stand and a filled stand, you should easily be able to notice a difference. The deader the better..."
http://www.audiocircle.com/index.php?topic=100728.0So I knocked...and tapped on the columns...
Where the pebbles were at the bottom, it was dead, above it it rang....and at the top, farthest from the pebbles, there was even more resonate ring.
.....re thinking...
Plan: I will gradually fill the cavity from densest material at bottom (pebbles), then next rice layer, equal amount in the columns, and finally top 1/3 kitty litter.
No air and the "density decreasing layers" should not detract ....with too much density nearest the base or bottom of the speaker. (That seems to really drag down my 805s and make them "appear more dense"....
Will try...I have a physics background in radiation, but sound physics is more in the "physical realm", thinking my above theory is a little of both.
Someone may find this useful.
I posted this a it really improved my soundstage to a new level of transparency!
I have to thank Noel at Skylan Speaker Stand Company in Canada... He is a master Craftsman..and true audiophile!
He has e mailed me a number of times, all with accurate and preside tips.
! Very personal service.
This below note is BEFORE I added the above improvement:
Set up with my B&W 805S speakers on the new stands...and played around with placement and read your thoughts on filling and types of fill...
http://www.diyaudio.com/forums/multi-way/152592-alternate-speaker-stand-damping-material.htmlI ended up with 13.5 lbs of pea pebbles (split equally in each of the 2 columns)/ stand, obtained from my local hobby store as it was clean, dry (and on sale!), hence the odd weight value...
....and used an "Isolate It" Sorbothane sheet to stick/lock the speakers to the top of the stands.
Their sorbothane products are great, Soft, but not too sticky.
http://www.isolateit.com/vibration-isolating-sheets-pads-4.htmlBrilliant sound!!!! ... extremely open and airy the 805Ss became "transparent yet more musical"... all at the same time.
..better by far from the original metal BW stands.
Could not be happier, and these stands look so very elegant and rock solid."
Reply from Noel:
Glad that the stands are working out.
Was wondering if you had tried the 6mm Bolts as this will sometimes make the unit more solid. My Importer in Germany uses soft plastic/rubber pellets as fill and swears it is the best overall Medium that he has tried,
http://www.skylan-stands.com/accessories.html Not sure where to get this stuff.
