[timbley]

I just got a couple of these off eBay:
https://www.ebay.com/itm/vidaXL-Set-of-2-Studio-Audio-Monitor-Speaker-Stands-Aluminum-Glass-Transparent/253474323782?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Deb4075de7bf146f6835405f7414e1448%26pid%3D100675%26rk%3D6%26rkt%3D15%26mehot%3Dag%26sd%3D273345198927%26itm%3D253474323782&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3A3023c5af-10e0-11e9-92bd-74dbd1800fdd%7Cparentrq%3A1dda3ace1680a688cbeeab36fff5eecf%7Ciid%3A1


These are weird, but interesting. The minute I opened the box I had regrets. The glass plates are quite resonant to a knuckle rap, and the aluminum tubes are only a little thicker than beer can aluminum. The base pieces between the lower glass plate and the aluminum tubes are just chromed plastic. Long steel threaded rods go from top to bottom with nuts on the bottom to squeeze everything together. The box had styrofoam sheets that broke into hundreds of styroballs as I opened the box. They have amazing static cling.

On the plus side, the stands went together nicely and both feel very solid, look nice, and hold the speakers up securely. They're nice examples of design simplicity, but might be better suited for holding up something other than speakers.

I listened to Gordon Lightfoot; Gord's Gold Vol. II and noticed it sounded brighter with less bass. This I expect because the speakers are now further from the floor. Vocals had good articulation so all the words were easy to hear. I sometimes have trouble hearing Gordon's words through the instrumentation on this album. But overall the highs didn't sound clean and fast like they did before.  Now that I'm in bed right next to one ( I sleep on a floor mat) I decided to give the speaker cabinet a knuckle rap. There's a distinct metallic sound and it sustains pretty well.  If I rap directly on the tubes I hear the same tone, but even more metallic. Rap on the glass plates, same tone loud and clear. These stands are very good resonators.

Now the fun begins. I've got to fix these things or they're going back, or will be used to hold up plants.

[rotarius]

So what speakers are you placing on them?  I would not necessarily jump to conclusions about the stands because of glass and maybe the tubes can be sand loaded?

[danali]

yoga blocks
6 bucks

[timbley]

So what speakers are you placing on them?  I would not necessarily jump to conclusions about the stands because of glass and maybe the tubes can be sand loaded?

I've got some Athena AS-B1 speakers on them. And I agree, I shouldn't jump to conclusions. It just shocked me how much of that metallic ring could be excited by knocking on the side of the speaker. These aren't the most inert speakers to begin with, but now they sound quite metallic. Take them off the stands and that goes away.

 I'm going to work with the stands and see what happens. Sand loading the tubes should be effective. They're not setup for it so I'll have to come up with a way to keep the sand from leaking out.

What I'd really like to do is successfully capture the effect as an audio measurement while playing test signals. If I am really hearing those tubes twang during music, it should show up on a mic measurement, and I should be able to show before and after differences from treating the tubes with sand.

[timbley]

yoga blocks
6 bucks

Thanks for that suggestion!

[rotarius]

You could try some simple things.  Place the speakers on dining chairs or something, sound the same or better?  You could also damp the stands temporarily with foam or rubber sheets to see if you can hear improvements.  The Athenas were bright speakers to begin with iirc.
The issues with vibration  are not properly understood by many folks.  You really want to measure the cabinet panel resonance frequency and amplitude with and without stands.  But you need the right tools or just use that Ebay return policy

[timbley]

My impression is that they sounded better sitting on old CD cases. But they were closer to the floor too. I need to keep as many variables the same as possible to make sure I know what I'm dealing with.
I've got the speakers bi-amped with a Behringer DCX. Last I measured they were smooth and flat both on axis and 30 degrees off. Not so crunchy sounding as with their passive networks. I was really digging them sitting on their CD cases. They just fell over too easily.
I just got a UMIK that I'm trying to learn to use with REW. Last measurement was with a Dayton Omnimic and associated software.

[timbley]

My first attempt at taking measurements with my new UMIK-1 and REW. Neat stuff! I just donated. REW is worth a lot more than I gave.

Looking for signs of something bad from those speaker stands. I'm not seeing anything obvious.
There's that bump in 3rd harmonic at 1.2k. It goes away off axis. Could that be something?

Measurements taken at 2 feet on axis with mic level with top of woofer.

[rotarius]

Those bookshelves sitting close to floor will sound dramatically different than elevated to correct height.  You just like the sound with the floor bounce better. 

[timbley]

Those bookshelves sitting close to floor will sound dramatically different than elevated to correct height.  You just like the sound with the floor bounce better.

I think you're right. Lifting them off the floor makes them need some baffle step boost to get a relatively flat response. Now that I've given then that boost, actually cut to the highs, they are measuring pretty flat again and I'm liking them! Not sure that I'm hearing anything bad from the stands at all.
A folded towel on top the stand for the speaker to sit on decouples them well enough that I don't hear the metallic noise when I rap on the speaker cabinet, or at least not nearly as loud.

[timbley]

Kitty litter is in the tubes  now. The metallic ringing is completely gone. I think the speakers sound better as a result. I'll take another measurement but I doubt I'll see anything. Are there some audible things that are really hard to measure? Or is it just the psychology of knowing that the stands are more inert?


The cat didn't seem to approve, but loading the tubes with fresh scented litter was quite easy with the help of a funnel. I get the impression that this is what was meant to be done by whoever designed these things.

[timbley]

I took a few measurements. The 3rd harmonic peak at 1.2k is down just a tiny bit, looks blunter.  Pretty much every frequency in the mids and highs now has slightly lower THD, but only by about 0.1 percent. I tried moving things around a bit and changing the level higher and lower to see if I could get increased THD readings. Couldn't do it. Couldn't get THD to measure as high as before the kitty litter treatment.
On the waterfall plot there was also a ringing at 1.2k that I didn't notice before. It falls off a little faster on all the kitty litter measurements.

I don't know if that small apparent improvement indicates anything important. Maybe it's just a difference in temperature and humidity.  Whatever, I'm at ease with these stands. They're just fine. I've got an emergency stash of kitty litter.