Speaker stands - is there objectivist evidence?

[617]

I worked in vibration analysis program for 2-3 yrs, measuring the vibration and on what axis is easy enough, the root cause of the vibration can be incredibly complex and very intertwined in structures, sub-structures and individual parts

What kind of things were you measuring? I'm trying to learn about vibration criterion and mitigation in the context of laboratory equipment and I share your impressions. Easy to characterize whats wrong and how bad it is, very very difficult to find the actual cause, and medium difficult to mitigate.

At least with lab equipment people can actually define what success looks like, with loudspeakers people can't even define what the goal is.

 

[617]

I'm sure it's not intended, but this comment is the typical "word salad" we hear all the time around speaker stands/feet/spikes. "decouple" means what? "share the load" means what? "dissipate the energy" means what?

It's never a matter of whether the energy is dissipated, it's a matter of the frequency and Q value, right?

The moving part of a speaker is literally suspended on a spring, and we're worried about coupling the cabinet to the floor?

 

[ZolaIII]

I'm sure it's not intended, but this comment is the typical "word salad" we hear all the time around speaker stands/feet/spikes. "decouple" means what? "share the load" means what? "dissipate the energy" means what?

Dispersion and entropy and those are complex physical phenomenons. You can't disperse long waves and energy doesn't disappear. You can move good part of it to (gather it there) a frequency you want be able to feel or hear. That's why I said silicone and not interested in hot water reinventing with property materials of similar characteristics. Simple Egg seater and cuple of books under will do the job very good. There are people who like vibrations and think they contribute to they physical feel of bass but they like more or less of them and that's totally fine with me. I like it as decoupled as possible.

 

[Yorkshire Mouth]

in this set up, do you have any issues with reflections off the desk?

It would appear, using the ‘mirror test’, you gave a flat, shiny area of desk at the first reflection point between speaker and listener.

 

[Esprit]

To isolate you need to look at visco -elastic material /open celled rubber, Sorbathane , then you will have to consider durometer and ‘height’ of the towers.

Genelec uses these:

 

[Somafunk]

in this set up, do you have any issues with reflections off the desk?

It would appear, using the ‘mirror test’, you gave a flat, shiny area of desk at the first reflection point between speaker and listener.

Yeah there is but I need the desk as I have spms and use the desk as an aid for standing/moving from one side of room to other, when thinking/comparing/designing a new setup for my room I knew what I needed to function daily and building that desk along the wall was a sensible move, as for desk reflections?, the absolute least of my worries/concerns

 

[Barrelhouse Solly]

For height I've used 4" OD PVC pipe connectors. Brought the tweeters up to ear level. I don't know about resonance. I'm big on the IMD--improvised musical device.

 

[Waxx]

From my non scientific experience as sound engineer on big dj rigs in the late 90's and early 00's, the best way to damp vibrations is a combination of mass and damping. We often used a combination of 2 heavy granite plates of about 2cm thick and a piece of isobothane sheet of about 3cm thick between it to avoid that the subs under the stage or in front of the stage gave feedback on the needle of the turntables of the dj. The whole dj setup (mixer + technics SL1200 turntables at that time, later also cdj's) was set on that, sometimes with a few dozen kilowatt of subs in front or below it. And it worked good enough for us. No jumping needles and no feedback loops trough the needles in our systems was the goal.

But the science behind it, i leave for others. And i don't know if that is the best way possible, i just know it worked well for us...

 

[Zapper]

It's never a matter of whether the energy is dissipated, it's a matter of the frequency and Q value, right?

The Q value is a measure of energy dissipation in a resonator. From Wikipedia, "It is defined as the ratio of the initial energy stored in the resonator to the energy lost in one radian of the cycle of oscillation." The lower the Q, the higher the damping, the more the energy dissipation.

The moving part of a speaker is literally suspended on a spring, and we're worried about coupling the cabinet to the floor?

Yes, because the magnet assembly is rigidly attached to the cabinet. For every force exerted on the speaker cone, there is an equal and opposite force exerted on the magnet and on the cabinet, which can create audible vibrations that can be conducted to the floor. The classic audiophile approach is to make the whole system as rigid and heavy as possible. I think the majority opinion here is the opposite: to insert flexible but highly damped couplings where possible to reduce transmission and to attenuate the transmitted energy.

Some audiophile practices make sense, like filling a hollow speaker stand with sand to add mass and to suppress resonances. Sand is a good damping material. But elastomers and/or thick carpet underneath the stands are better than spikes, to attenuate any vibrations passed to the floor as much as possible.

 

[Zapper]

From my non scientific experience as sound engineer on big dj rigs in the late 90's and early 00's, the best way to damp vibrations is a combination of mass and damping. We often used a combination of 2 heavy granite plates of about 2cm thick and a piece of isobothane sheet of about 3cm thick between it to avoid that the subs under the stage or in front of the stage gave feedback on the needle of the turntables of the dj. The whole dj setup (mixer + technics SL1200 turntables at that time, later also cdj's) was set on that, sometimes with a few dozen kilowatt of subs in front or below it. And it worked good enough for us. No jumping needles and no feedback loops trough the needles in our systems was the goal.

But the science behind it, i leave for others. And i don't know if that is the best way possible, i just know it worked well for us...

The science is solid. You made a heavily damped, low frequency low pass filter, comparable to an LRC filter. The elasticity of the isobothane (sorbothane?) sheet is comparable to an inductor, the damping of the sheet is comparable to a resistor in series with the inductor, and the mass of the slab is comparable to the capacitor. The heavier the slab and the more compliant the sheet, the lower the cutoff frequency. Enough damping is needed to suppress the resulting resonance, which could become a problem in itself.

 

[Zapper]

For height I've used 4" OD PVC pipe connectors. Brought the tweeters up to ear level. I don't know about resonance. I'm big on the IMD--improvised musical device.

Yoga bricks are another useful IMD. Firm enough to hold some weight, squishy enough to provide some damping.