Confusion on speaker stands versus floor standing

[Akustic]

One other thing that spikes and threaded feet offer- is the ability to level the speakers, or to at least insure that both speakers have exactly the same rake angles (forward-to-back tilt from bottom to top). This CAN DEFINITELY have a PROFOUND effect on the uniformity of frequency response and timing, relatively between the speakers, at the listening position.

I've had cases where speakers simply would not image properly in a room, sitting flat on the floor. Take that same speakers, put ihem on adjustable feet, and adjust the cabinet attitude so that both were identical- and voila- the soundstage just opened up. Just because both speakers were "launching" sound at the listener, identically, in terms of where one was in the frequency response dispersion pattern..

Regards,
Gordon.

Phase and timing ... our ears are exceedingly good at perceiving the location of a sound ..
Only took 50,000 years or so of evolution and natural selection ...

 

[Akustic]

I think I might be confounding things with how I'm using the word resonances ..

I'm talking about panel vibrations that are creating air movement that could create audible resonances out in the room and vibrations that interfere with the driver accurately moving air ..
Just to clarify and not confound an already complicated and confounding topic ..

Absorbent materials decouple two surfaces .. the one can't induce vibration in the other.
But they also trap panel vibrations in a speaker that is being energized and vibrated .. the vibrations continue until they dissipate through the air of the room and into and through the structures of the room ..

But ..
Decoupling is a good way to keep the big credenza box that people like to set speakers on from booming along like some big misshapen musical instrument ..

 

[GordonW]

I think I might be confounding things with how I'm using the word resonances ..

I'm talking about panel vibrations that are creating air movement that could create audible resonances out in the room and vibrations that interfere with the driver accurately moving air ..

Just to clarify and not confound an already complicated and confounding topic ..

That's what I was referring to, as well. Unwanted transmission of vibration from the walls of the speaker cabinet, to the air and/or surrounding, pliable, objects such as wood floors and such.

Regards,
Gordon.

 

[WillVT]

And every bit that the speaker energized that floor with sound- is an induced error in the frequency and transient response. That's something that could be easily seen in a waterfall plot, if someone had been inclined to make that measurement.

By making it small point contact as opposed to area contact- especially when the spikes or feet are generally in the stiffest areas of the cabinets (the corners), the transmission of vibration to the floor can be reduced by an order of magnitude, in many cases.

Regards,
Gordon.

This is the part that I have trouble understanding. Is the idea that because the area of contact is small, that less vibration energy is reduced?
That article I shared mentions someone who tested this, and found the opposite to be true, at least with cones between cabinet and stand. There are so many variables here though.

In some recent issues of the audio magazine, ‘Hi Fi News’ [ref 1], Keith Howard used an accelerometer to measure the levels of vibration in various objects. When he tried measuring the vibrations produced in a loudspeaker stand by playing the speaker he found a result that surprised him. With the speaker unit sitting on cones the level of vibration of the stand was over one hundred times greater than if the cones were replaced with small rubbery feet. This indicates that cones are of doubtful use if the intention is to stop vibrations passing from the speaker to the stand, or to any other solid objects against which the speaker may sit.

 

[GChief]

I can only go by what they did for my unique situation, they helped a lot.

 

[Akustic]

This is the part that I have trouble understanding. Is the idea that because the area of contact is small, that less vibration energy is reduced?
That article I shared mentions someone who tested this, and found the opposite to be true, at least with cones between cabinet and stand. There are so many variables here though.

In some recent issues of the audio magazine, ‘Hi Fi News’ [ref 1], Keith Howard used an accelerometer to measure the levels of vibration in various objects. When he tried measuring the vibrations produced in a loudspeaker stand by playing the speaker he found a result that surprised him. With the speaker unit sitting on cones the level of vibration of the stand was over one hundred times greater than if the cones were replaced with small rubbery feet. This indicates that cones are of doubtful use if the intention is to stop vibrations passing from the speaker to the stand, or to any other solid objects against which the speaker may sit.

It's easy to misunderstand ..

Those are the expected and preferred results if the cones are channeling the vibrations out of the speaker box and into the stands ..
Absorbing the vibrations isn't the point and can't be done .. there's energy there that is pumped in from the power company to the amp and then to the speakers ..
It has to dissipate ..

It can dissipate through the air off the box and create resonances or it can dissipate through the stands and into the floor ..

An earth ground is the only "absorber" of energy .. vibrational, electrical, mechanical .. just different forms or expressions of the energy.
Vibration circuit principles are similar to electrical circuit principles ..
Energy seeks an earth ground .

The spikes should be on the stands not the speakers or you're just creating one more resonant structure in the room .. the vibration needs to be drained into the larger structure of the building that's attached to the ground ..
The speaker can just be rigidly attached to the stand ..

 

[Akustic]

And every bit that the speaker energized that floor with sound- is an induced error in the frequency and transient response. That's something that could be easily seen in a waterfall plot, if someone had been inclined to make that measurement.

By making it small point contact as opposed to area contact- especially when the spikes or feet are generally in the stiffest areas of the cabinets (the corners), the transmission of vibration to the floor can be reduced by an order of magnitude, in many cases.

Regards,
Gordon.

That little point is reducing induced higher frequency vibrations into the floor but..

That little point also lowers the frequency potential of the path into the floor ...
And I for one want it draining into the floor and not resonating in my room ..
So it needs a path out of the box ..

 

[GordonW]

This is the part that I have trouble understanding. Is the idea that because the area of contact is small, that less vibration energy is reduced?
That article I shared mentions someone who tested this, and found the opposite to be true, at least with cones between cabinet and stand. There are so many variables here though.

In some recent issues of the audio magazine, ‘Hi Fi News’ [ref 1], Keith Howard used an accelerometer to measure the levels of vibration in various objects. When he tried measuring the vibrations produced in a loudspeaker stand by playing the speaker he found a result that surprised him. With the speaker unit sitting on cones the level of vibration of the stand was over one hundred times greater than if the cones were replaced with small rubbery feet. This indicates that cones are of doubtful use if the intention is to stop vibrations passing from the speaker to the stand, or to any other solid objects against which the speaker may sit.

He's testing a different phenomena. He's talking about Newton's Third Law motion of the whole cabinet (action-reaction), vs. panel vibration.

By reducing the coupling area of a vibrating panel- as well as having the only contact with the environment at the corners (where the panel can't vibrate), it cuts down the transmission of resonant energy to the floor.

And yes, using rubber feet at the corners might result in more isolation- but might be offset by an increase in Newton's Third Law (the cabinet may be driven forwards and backwards by the motion of the woofer, more). That's a trade-off that would have to be investigated.

Regards,
Gordon.

 

[Akustic]

He's testing a different phenomena. He's talking about Newton's Third Law motion of the whole cabinet (action-reaction), vs. panel vibration.

By reducing the coupling area of a vibrating panel- as well as having the only contact with the environment at the corners (where the panel can't vibrate), it cuts down the transmission of resonant energy to the floor.

And yes, using rubber feet at the corners might result in more isolation- but might be offset by an increase in Newton's Third Law (the cabinet may be driven forwards and backwards by the motion of the woofer, more). That's a trade-off that would have to be investigated.

Regards,
Gordon.

The whole idea of isolating speaker vibrations needs to be shot in the foot ..
Can't be done ...

Isolated where ?? ... Stored where where ?? Is it just sitting there waiting ?? What's it stored in ??
Meanwhile we're pumping in more energy for every minute that the music is on .. where's that going ??
The earth, and maybe ultimately black holes are the only storage facilities for energy ..

If we flipped this whole thing back into electrical terms .. since the electrical energy was converted into mechanical energy by the speaker in the first place.. we would be endlessly charging some object with no path to ground ... what object ?? what happens when it's full ?? How ??
Somewhere there's a path to ground, or the current won't flow . ditto with the vibrating mechanical energy ..

Like an electrical charge the mechanical energy charge will find a path to ground ..

Respects ...

 

[WillVT]

The whole idea of isolating speaker vibrations needs to be shot in the foot ..
Can't be done ...

Isolated where ?? ... Stored where where ?? Is it just sitting there waiting ?? What's it stored in ??
Meanwhile you're pumping in more energy for every minute that the music is on .. where's that going ??
The earth, and maybe ultimately black holes are the only storage facilities for energy ..

If you flipped this whole thing back into electrical terms .. since the electrical energy was converted into mechanical energy by the speaker in the first place.. you would be endlessly charging some object with no path to ground ... what object ?? what happens when it's full ?? How ??
Somewhere there's a path to ground, or the current won't flow . ditto with the vibrating mechanical energy ..

Like an electrical charge the mechanical energy charge will find a path to ground ..

My thought would be that one goal of any speaker setup would be to ensure that the greatest amount of mechanical energy possible would be released in the movement of the drivers, instead of being absorbed by the cabinet, the floor, the carpet, etc. A speaker that is kind of floating on a soft carpet will be able to move some, robbing the drivers of a little of their energy. In this case, spikes through the carpet would hold the cabinet more rigidity to the floor, allowing the driver to express more of it's energy.

I'm not a physicist, but all the talk of different frequencies not passing through the small tip of a spike seems a little bogus to me. I think it's all just about making the cabinet as sturdy and rigid as possible.

 

[Akustic]

My thought would be that one goal of any speaker setup would be to ensure that the greatest amount of mechanical energy possible would be released in the movement of the drivers, instead of being absorbed by the cabinet, the floor, the carpet, etc. A speaker that is kind of floating on a soft carpet will be able to move some, robbing the drivers of a little of their energy. In this case, spikes through the carpet would hold the cabinet more rigidity to the floor, allowing the driver to express more of it's energy.

You can say that two times ..
That has to be the goal .. and holding that driver basket as firmly and fixed as possible in the horizontal plane is about the only way to achieve that goal ..

 

[Akustic]

I'm not a physicist, but all the talk of different frequencies not passing through the small tip of a spike seems a little bogus to me. I think it's all just about making the cabinet as sturdy and rigid as possible.

That's forever and easily misunderstood ..
The vibrations don't go away .. sturdy rigid cabinet's can't absorb vibration, but they can change it's frequency .. they're there, but less audible ..
Same with any "absorbent" material .. It isn't "absorbing" the vibration, it's just changing it's frequency ..

Vibration passes through the tip .. but if it's contact area is reduced it is less able to induce/create higher frequency audible vibrations in the item that it is sitting on ..

 

[Sgt Shultz]

The whole idea of isolating speaker vibrations needs to be shot in the foot ..
Can't be done ...

Isolated where ?? ... Stored where where ?? Is it just sitting there waiting ?? What's it stored in ??
Meanwhile we're pumping in more energy for every minute that the music is on .. where's that going ??
The earth, and maybe ultimately black holes are the only storage facilities for energy ..

If we flipped this whole thing back into electrical terms .. since the electrical energy was converted into mechanical energy by the speaker in the first place.. we would be endlessly charging some object with no path to ground ... what object ?? what happens when it's full ?? How ??
Somewhere there's a path to ground, or the current won't flow . ditto with the vibrating mechanical energy ..

Like an electrical charge the mechanical energy charge will find a path to ground ..

Respects ...

That energy can also be turned to heat and released through different materials.

Quoting John Atkinson

"The sealed cabinet is constructed from "extremely stiff, ultra-high-density multi-fiber panels laminated to an acoustically absorptive, visco-elastic substrate." After reading that, you can probably understand that the very first thing I did was to subject the cabinet to the knuckle-rap test. Well, the cabinet is "dead". All I got for my pains were sore knuckles"

 

[Akustic]

A guitar uses very thin sheets of wood for a reason .. It's easy to resonate and amplify those string vibrations and bounce them back through the hole ..
A guitar made of half inch ply would sound like sh** ..

Might be the reason that most guitar players own an electric and an acoustic guitar ..

 

[Akustic]

That energy can also be turned to heat and released through different materials.

Quoting John Atkinson

"The sealed cabinet is constructed from "extremely stiff, ultra-high-density multi-fiber panels laminated to an acoustically absorptive, visco-elastic substrate." After reading that, you can probably understand that the very first thing I did was to subject the cabinet to the knuckle-rap test. Well, the cabinet is "dead". All I got for my pains were sore knuckles"

As it should be ..
Sounds better that way ..

 

[Gigantic]

Yes, that's pretty much the received wisdom in the hi-fi world. The idea is that if the loudspeaker cone moves forwards the cabinet must move backwards due to conservation of momentum. Momentum equals mass times velocity, so if we consider the masses involved we can get a better idea of what's going on. Here's an 8" driver picked at random from Parts Express.

FaitalPRO 8FE300 8" Professional Midbass 8 Ohm

FaitalPRO 8FE300 8" Professional Midbass 8 Ohm FaitalPRO’s FE300 series has been designed and built as a direct response to the overwhelming demand for an evolved and more powerful series of products which would enhance the universally successful FE200 series. Building on this original idea...

www.parts-express.com

The mass of the cone (including airload?) is 22.9 grams. What's the mass of a loudspeaker cabinet? That could be anywhere within a wide range, but lets pick another speaker at random just to get a ballpark figure. Parts Express sell one pair of speakers with an 8" woofer, the Yamaha NS-6490.

CLEARANCE Yamaha NS-6490 8" 3-Way Acoustic Suspension Bookshelf Speaker Pair

Yamaha NS-6490 8" 3-Way Acoustic Suspension Bookshelf Speaker PairThe Yamaha NS-6490 bookshelf speakers are workhorses, handling up to 140 watts, they will take whatever you throw at them. These speakers work well in a stereo configuration or in your home theater system as left and right...

www.parts-express.com

The weight is given as 28.95, but no units are given. (???) Yamaha's website says the speakers weigh 13.2 lbs, which is 5987 grams. That's probably for a pair of speakers and PE's figure is in kilograms for a single speaker. Assuming the cone is around 22.9 grams (same as the other 8" driver), the ratio of cone mass to cabinet mass is 1:261. So, could cone motion cause a significant movement of the cabinet with the cabinet being 261 times as heavy? I suppose that would depend on what's considered significant and the point is debatable. The idea of rigid coupling of speaker cabinets to the structure of the room is to add the mass of the structure to the mass of the cabinet so that the ratio of cone mass to "the other mass" is further increased.

In the studio world a different approach is taken and speakers are often isolated from the room structure by compliant mounting. Their theory gives two benefits.
Firstly the speed of sound in solids is generally faster than the speed of sound in air.
The speed of sound in air is 343m/s. The speed of sound in wood and concrete is approximately ten times that, so if a loudspeaker is rigidly coupled to the room structure it can travel through the structure to the listener faster than it can travel through the air to the listener, and that is what causes the smearing effect. Therefore compliant mounting reduces smearing.
The second benefit of compliant mounting (ie decoupling) is that it prevents the loudspeaker cabinets from causing the room structure to vibrate and therefore prevents the room from becoming an uncontrolled resonator and secondary source of sound.

To be honest, the studio theory sounds more convincing to me and there does seem to be an increasing number of loudspeaker isolation products available in the hi-fi market too, so maybe the studio approach is starting to win the argument.

Anyway, the point I was trying to make to the OP is post #3 is that loudspeaker stands don't necessarily prevent the speaker from being rigidly coupled to the floor in the same way as spikes under floorstanders rigidly couple those speakers. However, the benefits of rigid coupling are debatable anyway.

Good points and ironically, and perhaps this is just me, but I want two different things from my recording studio setup and my Hi-Fi. My studio monitors are nearfield and decoupled and room response is negated, for the most part. Both the monitors and the amp driving them have a relatively flat response and the speakers primarily produce mid-bass and roll off relatively high, around 45-55Hz. While I have a small subwoofer in my studio, I do the lion’s share of my mixing without it.

Out in my living room, where I do most of my active listening, my setup is radically different. My speakers are spiked and have a wide range, from 28hz-20khz. While I tuned my crossovers for a flat response, I’m also taking advantage of room gain and proximity effect to enhance both ends of the spectrum, for increased bass and treble, although I’m not using any eq apart from parametric eq in my dsp crossover to even some bumps in the response curve in near field measurements. Whereas I would characterize my studio setup, an Alesis RA150 power amp and a pair of vintage KRK Rock-It passive monitors as flat and analytical, I would describe my Hi-Fi as dynamic, exciting and supremely enjoyable to listen to.

 

[GChief]

Good points and ironically, and perhaps this is just me, but I want two different things from my recording studio setup and my Hi-Fi. My studio monitors are nearfield and decoupled and room response is negated, for the most part. Both the monitors and the amp driving them have a relatively flat response and the speakers primarily produce mid-bass and roll off relatively high, around 45-55Hz. While I have a small subwoofer in my studio, I do the lion’s share of my mixing without it.

Out in my living room, where I do most of my active listening, my setup is radically different. My speakers are spiked and have a wide range, from 28hz-20khz. While I tuned my crossovers for a flat response, I’m also taking advantage of room gain and proximity effect to enhance both ends of the spectrum, for increased bass and treble, although I’m not using any eq apart from parametric eq in my dsp crossover to even some bumps in the response curve in near field measurements. Whereas I would characterize my studio setup, an Alesis RA150 power amp and a pair of vintage KRK Rock-It passive monitors as flat and analytical, I would describe my Hi-Fi as dynamic, exciting and supremely enjoyable to listen to.

My situation where spikes were required was KG4s near field. And to @Akustic s point about guitars this was a 92" x 82" finished oak playwwod floor over extruded aluminum frame. I do not have any pics after the spikes and monitor isolation pads. The improvements were dramatic. This was before any of the room treatments started.

 

[Sgt Shultz]

As it should be ..
Sounds better that way ..

But very few are

 

[motorstereo]

I never finished in the highest percentile in school and didn't take physics in either grade school or high school. I'm not sure of Newton's 1st, 2nd or 3rd theory either. What I do know my main speakers sound better spiked simply because I tried it. But spiking the sub didn't work so it's back to rubber feet for that situation. Perhaps rather than argue theories maybe try spiking and see if it works whether or not physics classes say it should or should not.

 

[Akustic]

I never finished in the highest percentile in school and didn't take physics in either grade school or high school. I'm not sure of Newton's 1st, 2nd or 3rd theory either. What I do know my main speakers sound better spiked simply because I tried it. But spiking the sub didn't work so it's back to rubber feet for that situation. Perhaps rather than argue theories maybe try spiking and see if it works whether or not physics classes say it should or should not.

Trying it is the way that the State of the Art proceeds ... ask Richard Vanersteen ...
But sometimes understanding it makes you think of something else to try ..

And we all know a lot about the laws of physics .. we just don't know the names ..
Except for Newton .. we've just all dropped something on our foot .. Newton's first law .. always the foot ..