Springs Under My Speakers: What's Happening?

[DMill]

I have speaker stands that can be filled with sand. I never bothered doing it. For one thing it would just make them heavier to move around. For another I doubted
it would make much difference to the sound, which I still tend to doubt. (Though I'm open to the idea).

The only benefit I could ever see was to make them less prone to getting knocked over by kids or pets. But even then, a rolling tackle by a 10 year old is gonna knock them over. I did lose a floorstander once to a cat who like to jump on top. Knocked it over and busted the tweeter and put a giant ding in the side of the cabinet. It was B&W CM4. Cost me close to grand to replace the speaker. Should’ve replaced the cat. Lol

 

[Sal1950]

But it will bug me until the end of days if I don't fill the other one. So I will, of course I will.

LOL, you know you have too.
Then empty one and fill it with lead shot and compare to the sand filled one.
Then empty one and fill it with steel shot and compare to the sand and lead filled ones.
I've read that it all makes audible differences for years.

 

[jdjung]

But did the thread help you to decide if you should fill your speaker stands?

I have a bag of fancy-sand from the days when I sold audio. It was costly when I sold such things, it should suffice for a test. If I see differences, perhaps I will follow up with more materials. I also have a pair of Paradigm Export Monitors, a fine speaker to test the stand-filling hypothesis. They are firmly bolted to steel stands with isolation patches. The stands do ring a bit.

I set up a mic at 1 meter, carefully marking the speaker's position since that is critical.
View attachment 300806

I measured the speaker, then filled it with the sand.
View attachment 300808
I returned the speaker with the stand filled with sand to the same position and (without moving the microphone) repeated the measurement.
Red is with No Sand. Green is with the stand filled With Sand.
View attachment 300811
The differences are tiny. Could it be positioning? I tried to get the speaker to within a few millimeters of original position. I will test for how sensitive the speaker is to position.
I rotated the speaker with the stands filled with sand by moving off axis keeping the distance to the microphone the same. It's only a couple millimeter nudge, about 2 degrees horizontal rotation.
View attachment 300813
A much larger difference is seen due to rotation than can be attributed to sand-filling.
How about vertical? I tilted the speaker back by elevating the front by about 2mm (also a couple degrees of tilt).
View attachment 300814
No surprise the small vertical shift affects the sound more than horizontal:
View attachment 300815

These two results show we can't tell if the tiny differences measured after sand-filling is just tiny changes in placement.

Lastly, how about moving the speaker 8 inches closer to the wall, keeping the mic (as best I can) same distance and orientation to the speaker.
View attachment 300816
This says way more about my room than about sand in my stands. You can see the room mode at 40Hz is unaffected, that's because I moved the speaker closer to the back wall and this mode in my room is transverse to that. I did change the 55Hz mode's depth since that is from front to back wall and the change in position is changing how the speaker is energizing that mode. The peak that moves from 120 to 140Hz and the one that moves from 180 to 200 are cancelation from the back wall. See here for instance:

Monitor Placement - Genelec.com

To create the ideal listening experience, several aspects need to be taken into account when placing the monitors within the listening space. First, you need to identify the listening area within the space and consider where the listener will be placed in relation to the space as well as the...

www.genelec.com

In summary.
I did the time-honored (and slightly messy) task of filling one of my speaker stands with sand. I measured nearly zero difference in sound before and after the stands were filled with sand. I also measured the tolerance of the experiment to speaker and mic placement and showed that tilting speaker position by just a few millimeters in the horizonal or vertical plane made a much larger difference in the sound than the addition of sand to the stands. This gives some confidence that I got the speakers positioned in the same place after filling the stands. I also found that positioning the speakers 8 inches closer to the wall made a much more dramatic impact on the sound than treating the stands with sand.

The room and relative position sensitivities are no surprise. I can't hear the small differences in horizontal or vertical tilt. I can hear the differences in bass as I move the speaker a relative to the back wall. I certainly can't hear the impact of sand in the stands. I can't even measure a difference and the mic is way more sensitive and quantitative than my ear.

Wow thank you! Saves me the possibility of spilling KEF's acoustic innert filler everywhere.

 

[Doodski]

That's a reversed case study of a highly microphonic component.
Engineers have been working on TT isolation since near day 1.
Some change is to be expected and differences easily measured.

It was this tiny little house. I was ~18 and I rented it. I weighed the main floor down with cinder blocks and stopped it from bouncing, rumbling and feedback. There was still air born feedback but it was not too bad.

 

[Ken Tajalli]

I have speaker stands that can be filled with sand. I never bothered doing it. For one thing it would just make them heavier to move around. For another I doubted
it would make much difference to the sound, which I still tend to doubt. (Though I'm open to the idea).

Antibiotics are very effective if one has a bacterial infection. It won't do anything for diabetes ( I guess). Does this mean the drug is a snake oil?
If you have a flimsy metal stand, which suffers from resonances of its own, then filling it with sand or lead shots can help, otherwise it won't .
It is madness to imply that because it didn't work on a good stiff stand, then it must be an old wives tale.
Horses for courses.

 

[Purité Audio]

Any ‘resonance’ must be audible,
Keith

 

[MattHooper]

Any ‘resonance’ must be audible,
Keith

Springs Under My Speakers: What's Happening?

LOL, let's keep going, prove that you have a window. I want proof Purite Audio even made that post before it's worth answering. Could have been hacked. Or his wife posted while he wasn't looking.

www.audiosciencereview.com

Don't leave us hangin'.........

 

[MAB]

Antibiotics are very effective if one has a bacterial infection. It won't do anything for diabetes ( I guess). Does this mean the drug is a snake oil?
If you have a flimsy metal stand, which suffers from resonances of its own, then filling it with sand or lead shots can help, otherwise it won't .
It is madness to imply that because it didn't work on a good stiff stand, then it must be an old wives tale.
Horses for courses.

The stands I tested were not very expensive, steel, and somewhat resonant. Filling with sand made no difference in the sound.
Flimsy does not equal resonant. Bells are not flimsy but are resonant, for instance. You equated the two.
And, sand won't fix flimsiness. Better off upgrading to a better stand, it's not like it's expensive.

 

[Ken Tajalli]

The stands I tested were not very expensive, steel, and somewhat resonant. Filling with sand made no difference in the sound.
Flimsy does not equal resonant. Bells are not flimsy but are resonant, for instance. You equated the two.
And, sand won't fix flimsiness. Better off upgrading to a better stand, it's not like it's expensive.

I said "suffer from".
If it made no difference , or it was not audible or measureable, then iy didn't suffer from its own resonances.
At any rate, dry sand or play sand sells for a few pounds a large bag over here!
Good enough to experiment with and have fun with.
It can't do any harm, as your measurements have shown.
A fancy expensive acoustic sand, is indeed snake oil.
builders dry sand, or play sand is all one needs.

 

[Pareto Pragmatic]

I tried some. Please keep in mind that I have a very bouncy floor and choose to use fairly lightweight stands. Stuff moves.

First I took some springs out and created a perpetual motion machine. So I put the OG springs back in, max rated for 70lbs with four, for 30-35lbs of speaker and stands.

Here's my current system (silicone hemispheres replace the spikes, set on an old kitchen gel mat, so the hemispheres sink deep enough to bring the outside edge of the baseplate in contact with the mat), no eq:

Here's with the springs on the mat and supporting the stand:

Sounded bad too post eq. Veiled.

On the upside, it toned down some narrow dips 100-450hz, at the cost of increasing some dips 500-1300hz. So I expect that if I softened the springs, I would shift that effect lower.

I thought about throwing some weights and bungie cords into the mix, to create a damping system. But nah. Given my extreme case, springs are a non-starter compared to what I have now.

 

[Pareto Pragmatic]

The stands I tested were not very expensive, steel, and somewhat resonant. Filling with sand made no difference in the sound.

I have steel. I wanted light, because I move them a lot as they are in the main room, so no sand. Foamed the insides, do not recommend. It kills internal resonance I am sure, but does little to the overall resonance of the stands.

What I do recommend is wrapping bungie cords around them. I have some around both pillars, not too tight and not too loose, at two different heights. The tap test tells you the correct tension. So long as they go around the structural elements completely (full circle + a bit more, overlap the cord), they made the tap test sound pretty "dull" and took most of the ringing out.

 

[JohnnyAudio]

You have inspired me!
Instead of springs, I will make an isolation pad with tennis balls, about 20" X 20" of tennis balls hot melt glued together.
This will prove to my audiophile friends how crazy I am.
I will try my subs first, if there is an improvement, then I will make pads for main speakers.
Stand by for the volley.

 

[MAB]

I have steel. I wanted light, because I move them a lot as they are in the main room, so no sand. Foamed the insides, do not recommend. It kills internal resonance I am sure, but does little to the overall resonance of the stands.

What I do recommend is wrapping bungie cords around them. I have some around both pillars, not too tight and not too loose, at two different heights. The tap test tells you the correct tension. So long as they go around the structural elements completely (full circle + a bit more, overlap the cord), they made the tap test sound pretty "dull" and took most of the ringing out.

It's just that none of this makes a measurable difference. And not audible. Sand, concrete, foam, or just leave them unfilled, it just doesn't matter.

 

[OldHvyMec]

It's just that none of this makes a measurable difference. And not audible. Sand, concrete, foam, or just leave them unfilled, it just doesn't matter.

If wrapping the stands with a dampening material like rubber rope/bungies does what you like then pouring the inside with @Soundcoat or @Flex seal
will do the same and not be near as gaudy.

Some people like the WEIGHT because of kids and the fact that they move over time IF there is a serious sub-system on a stem wall foundation. If you
can't tell the difference between removing a huge passive driver like a suspended floor by decoupling the cabinets, I'm pretty sure you think room treatment
is a load of crap too.

There is nothing worse in my listening experience than feeling the sub through my A$$ vs feeling the thump of a tight clear 100-150hz signal in my chest.
It's NOT the problem of changing the measurement it's the fact of cleaning up the differences between different instruments like a set of congas vs a double bass vs
a snap vs a low note on a bass guitar. It's the distortion that muddies the sound or harmonics you don't want over long slops. EX: a piano note with the dampener
peddle depressed to remove the dampening.

It needs to measure pretty flat AND be clear to the ear. Music like the old "POP" is a great example of great sub and great bass and a distinction between the two
not the ADDED distortion or muddiness between 30-80hz and 100-150hz because you didn't control that HUGE passive driver called your floor.

Valve/Tube/Turntable guys especially want to control that vibration in any playback system.

I run up to 70 valves at a time. There is a HUGE difference in the clarity between DE-coupling and spikes especially. If that is not an issue for your ears, maybe you're
blessed and I'm cursed. In other words, if I can FEEL the sub/bass through my feet/butt I did something wrong. It might be the reason I like an air-ride/shock seat in my
PU too. Oscillation (back and forth) option too, for a very bumpy (or worse) choppy surface road and no load in the bed.

I still go to a lot of oilfield sites and the roads will shake your teeth out even with the best of suspensions. I prefer being the little bobble-head in the window not
the bags of concrete in the bed.

Regards

 

[MattHooper]

If wrapping the stands with a dampening material like rubber rope/bungies does what you like then pouring the inside with @Soundcoat or @Flex seal
will do the same and not be near as gaudy.

Some people like the WEIGHT because of kids and the fact that they move over time IF there is a serious sub-system on a stem wall foundation. If you
can't tell the difference between removing a huge passive driver like a suspended floor by decoupling the cabinets, I'm pretty sure you think room treatment
is a load of crap too.

There is nothing worse in my listening experience than feeling the sub through my A$$ vs feeling the thump of a tight clear 100-150hz signal in my chest.
It's NOT the problem of changing the measurement it's the fact of cleaning up the differences between different instruments like a set of congas vs a double bass vs
a snap vs a low note on a bass guitar. It's the distortion that muddies the sound or harmonics you don't want over long slops. EX: a piano note with the dampener
peddle depressed to remove the dampening.

It needs to measure pretty flat AND be clear to the ear. Music like the old "POP" is a great example of great sub and great bass and a distinction between the two
not the ADDED distortion or muddiness between 30-80hz and 100-150hz because you didn't control that HUGE passive driver called your floor.

Valve/Tube/Turntable guys especially want to control that vibration in any playback system.

I run up to 70 valves at a time. There is a HUGE difference in the clarity between DE-coupling and spikes especially. If that is not an issue for your ears, maybe you're
blessed and I'm cursed. In other words, if I can FEEL the sub/bass through my feet/butt I did something wrong. It might be the reason I like an air-ride/shock seat in my
PU too. Oscillation (back and forth) option too, for a very bumpy (or worse) choppy surface road and no load in the bed.

I still go to a lot of oilfield sites and the roads will shake your teeth out even with the best of suspensions. I prefer being the little bobble-head in the window not
the bags of concrete in the bed.

Regards

As detailed in this thread, at first, I thought I wanted full decoupling, and when I got it, I no longer felt the music through my chair, etc.
I found I ended up preferring some of that feeling, so I ended up doing some coupling to the floor. A sort of “ halfway between coupling and decoupling” which got me exactly what I wanted.

 

[JohnnyAudio]

In the end, don't we want to pressurize the room?

 

[Pareto Pragmatic]

It's just that none of this makes a measurable difference. And not audible. Sand, concrete, foam, or just leave them unfilled, it just doesn't matter.

I agree in general, but there are some cases where it will make a difference.

Sand/weight would make a difference in my room. It would shift a peak near 30 lower a bit, and make all the things my floor does happen at slightly higher SPL. That's just from the weight (think of tuning a driver by altering the weight of the cone). But if the stands resonate at a frequency that lines up with one/some of the MANY resonances in my floor, resonances that change with SPL, then stopping those will show a measurable difference.

I have tried things that don't change the measurements, I have tried things that do a bit but no audible difference, and I have tried things that make for immediately clear and obvious audible differences

I don't think you understand the issue in such a room. At 80db/1m levels with no EQ, my couch that sits near the middle of the room will be moving vertically, with my weight on it, and I will see a big spike at 200hz when that starts to happen, and a drop in all freqencies below that. It's not that a stand resonating does all that much on its own, it's that such a resonance aligns with the floor, which shoots up at the ceiling creating positive reinforcement, and that will get back into the stands and reinforce the resonance further.

Floor resonances shift and change in ways room modes just don't. A dip at 60 turns into a peak, for example, but ONLY when 30 rises to a certain level. And when 60 starts to shoot up, 30 drops. It's more complicated than that, but that is one example of how floor energy interacts compared to standing waves in a room. The energy shifts its distribution around.

That said, even in my room, most things I have tried have had a small effect and that effect is limited to a relatively small range of frequencies. The ones that matter are the ones that line up with what my floor is doing at a given SPL. I am quite sure that things that have an audible effect in my room would have no audible effect if I had a concrete floor. Or any normally behaving floor for that matter.

If wrapping the stands with a dampening material like rubber rope/bungies does what you like then pouring the inside with @Soundcoat or @Flex seal
will do the same and not be near as gaudy.

If I had thought of that/read about it I would have done that, it's a good idea. The bungies were a test of concept. I will also say that black paracord would not stand out against a black stand. But my stands go out of sight when not in use, and I don't care about how they look, so I just left it as is.

As detailed in this thread, at first, I thought I wanted full decoupling, and when I got it, I no longer felt the music through my chair, etc.
I found I ended up preferring some of that feeling, so I ended up doing some coupling to the floor. A sort of “ halfway between coupling and decoupling” which got me exactly what I wanted.

I get what you are saying here. I too find I happy medium between strongly and weakly coupled speakers.

Since I have never totally decoupled the speakers, which would require hanging them from the ceiling, I find that a slight SPL adjustment dials in the sound I want. I can't stop my floor, but I can delay it doing things I can't correct. Controlled somewhat with EQ, but that fails with higher SPL. So somewhere, +/-2db or so from my normal volume level, I will get just enough floor but not too much. I trim the effect with volume based on low bass content, pretty much.

200hz spike, things go bad fast. That's the line I can approach but not cross. Luckily, my desired SPL sits pretty close to, but lower than, this point.

In the end, don't we want to pressurize the room?

Yes. It would be good to make sure all the room modes are engaged before measurement and EQ.

But in my room, I have 4 doorways that open into the rest of the house, so it takes a LOT to get fully loaded. More when the weather is nice and the house is not sealed up. Those doorways, at the levels I listen to, do have a pressure gradient, in that at certain levels and higher I can clearly feel the pressure difference when walking though the doorways. I consider that to be pressurized "enough". The room modes show up and are stable. The floor issues keep changing things, but the room modes are stable. That's what I look for in terms of pressurization, stable room modes.

 

[OldHvyMec]

In the end, don't we want to pressurize the room?

Actually, NO in my case. It leads me to early listening fatigue that I never have with my system by simply opening the double French doors at one end of the room. That opening also acts as a weir for reflective/returning waves coming back into the room. It's not 100% but it does help with room reverberance/distortion.

I prefer phase plug tec for the same issue. Returning waves.

OB servo/subs are a good example of how the room can be sealed and then loaded, causing your actual eardrums less fatigue. At least in my case.
Opening a door/window is another way of doing the same thing. Much like opening your mouth when there is very heavy bass (air movement) in a small
space like a car/van. Raspberrying your lips is a technique used by bass heads and HD mechanics all the time around 110-130+ DB noise where even plug
and muffs are not adequate.

As detailed in this thread, at first, I thought I wanted full decoupling, and when I got it, I no longer felt the music through my chair, etc.
I found I ended up preferring some of that feeling, so I ended up doing some coupling to the floor. A sort of “ halfway between coupling and decoupling” which got me exactly what I wanted.

As long as the tonearm isn't skipping across the platter or not affecting the valves in the valve gear you're using or rattling china in the front room, I guess it's OK.
I use a lot of valves in some of my setups. It just takes ONE (valve) to become sensitive to vibration and wreak havoc. Not to mention the reduction in actual valve
longevity.

It's like adding tube/valve o-rings to valve glass (in my case and it sounds like yours too). It does something you like or don't like. In my case, I've never liked using
them. It's like throwing a blanket over a speaker in some cases.

Decoupling for me is a tube/valve lifesaver, not to mention the way it cleans up the sub/bass region so I can distinguish the difference between
instruments and induced reverb in any given room/space. Certain harmonics are very destructive especially when you see the sheetrock screws backing out of the
wall. LOL Cancelation is another alternative with Helmholtz tec but I still isolate the resonators from the room's boundaries or large surface areas. Usually with
dampened spring pack, air-ride or both.

I've seen several expensive power plants (30-200K) destroyed because of dampening loss or worse not enough or the wrong kind, to begin with.

Speaker driver fasteners, coming loose or backing out are a good example. Seldom does a screw come loose if it's dipped in silicone and then installed.

Regards

 

[izeek]

I tried some. Please keep in mind that I have a very bouncy floor and choose to use fairly lightweight stands. Stuff moves.

First I took some springs out and created a perpetual motion machine. So I put the OG springs back in, max rated for 70lbs with four, for 30-35lbs of speaker and stands.

Here's my current system (silicone hemispheres replace the spikes, set on an old kitchen gel mat, so the hemispheres sink deep enough to bring the outside edge of the baseplate in contact with the mat), no eq:

View attachment 425986



Here's with the springs on the mat and supporting the stand:

View attachment 425987


Sounded bad too post eq. Veiled.

On the upside, it toned down some narrow dips 100-450hz, at the cost of increasing some dips 500-1300hz. So I expect that if I softened the springs, I would shift that effect lower.

I thought about throwing some weights and bungie cords into the mix, to create a damping system. But nah. Given my extreme case, springs are a non-starter compared to what I have now.

may i suggest trying a concrete paver with a dense mat between it and floor.

thats my current solution. i tried rubber/cork and rubber/sorbothane pads, different woods and thickness of, mdf, and the pavers. everything you try will make a difference. i truly hated the rubber/sorbothane pads. sucked the life out of the sound. everything else was a plus in the succession i listed.

so, my towers are naked-footed on a paver with a horsestall mat under it. the subs are on substands on the paver. my floor is carpeted wood.

this did a great job at reducing those floor and wall resonances. cut down on some room gain as well, it seems. i can play it louder without hearing it outside my door. much cleaner, tighter bass but improvements across the board.

my next trick will be granite plinths. i saw some on a couple of forums under gear way better than mine. nicer looking and about 10-15% more dense.

im not good with the measurements thing. i do like what i hear. ymwv.

 

[Purité Audio]

I would really like to see some measurements that corroborate your perceived differences.
What physical mechanism is responsible for the sound do you imagine?
Keith