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Springs Under My Speakers: What's Happening?

steve59

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I have no interest in the science of playback, only the event. wait, did I just kick myself off this forum?
 

Purité Audio

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No not at all, but there are many other forums, that actively support and indeed encourage your ‘ uneducated and proud of it‘ stance.
Keith
 

steve59

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uneducated and proud of it sounds a bit condescending. That I choose 2 channel over mono because I appreciate the illusion it creates and I don't want to interfere with the process translates to uneducated? Why are you in the market?
 

Sal1950

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My income doesn't afford me the Kef Blades, but i'm going to keep them as long as I can.
I'm confused,
You've got a $32,000 set of speakers on loan?
Nice dealer
And you list them in your signature?
 

Tim Link

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I'm posting here again what I just posted on another thread, my thought that the benefit of suspending speakers is not about eliminating transmission of cabinet vibrations to the floor, but about damping the floor. Sound waves in the air are primarily what is exciting the floor, and by suspending the speakers you are turning the speakers into floor dampers. If I'm right you could get rid of the negative consequences of suspending the speakers and gain back the positives by using something else to damp the floor. The speakers may not be in the best place. Other pieces of furniture, equipment racks, or maybe the subwoofers could be used as floor dampers by putting them on springs and moving them around until they work best. You could put yourself and your listening chair on springs! I don't think a speaker or other object has to be particularly heavy to be effective. It probably depends on the frequency you are targeting. There are products available called stud dampers which are basically blocks of wood that are placed on the sides of wall studs with a spring attachment. When the stud vibrates the spring loaded block vibrates out of sync and absorbs energy, damping the stud. I don't see why the exact same thing wouldn't happen with a spring loaded object on the floor.
 

Frank Dernie

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I'm posting here again what I just posted on another thread, my thought that the benefit of suspending speakers is not about eliminating transmission of cabinet vibrations to the floor, but about damping the floor. Sound waves in the air are primarily what is exciting the floor, and by suspending the speakers you are turning the speakers into floor dampers. If I'm right you could get rid of the negative consequences of suspending the speakers and gain back the positives by using something else to damp the floor. The speakers may not be in the best place. Other pieces of furniture, equipment racks, or maybe the subwoofers could be used as floor dampers by putting them on springs and moving them around until they work best. You could put yourself and your listening chair on springs! I don't think a speaker or other object has to be particularly heavy to be effective. It probably depends on the frequency you are targeting. There are products available called stud dampers which are basically blocks of wood that are placed on the sides of wall studs with a spring attachment. When the stud vibrates the spring loaded block vibrates out of sync and absorbs energy, damping the stud. I don't see why the exact same thing wouldn't happen with a spring loaded object on the floor.
This is not likely to be correct.

Using a mass on a spring is commonly used as a "damper". It isn't strictly a damper it is a mode shape changer. Adding a mass on a spring tuned to a problematic frequency and mounted at an antinode of a problematic vibration is commonly used in machine tools and engines.
OTOH it would not work as you write since at the frequency it calms in the problematic location the mass on spring is vibrating like mad, so what you imagine may happen will not.

It genuinely is the speaker being isolated from the floor by mounting it on appropriate rate and spacing of springs.
 

Tim Link

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This is not likely to be correct.

Using a mass on a spring is commonly used as a "damper". It isn't strictly a damper it is a mode shape changer. Adding a mass on a spring tuned to a problematic frequency and mounted at an antinode of a problematic vibration is commonly used in machine tools and engines.
OTOH it would not work as you write since at the frequency it calms in the problematic location the mass on spring is vibrating like mad, so what you imagine may happen will not.

It genuinely is the speaker being isolated from the floor by mounting it on appropriate rate and spacing of springs.
You could be right. I'm envisioning an experiment involving a large plywood board and a speaker. What I'm thinking of doing is suspending the speaker just 1/4" in front of the plywood, and then solidly connecting the speaker to the plywood, and then using spring loading between the plywood and the speaker. What I'm interested in hearing is how much audible vibration is coming off the cabinet, and how much more audible can I make it by directly coupling the speaker to the plywood. Also, how much can I get the plywood to vibrate without the speaker even touching it at all. My past experience is that the plywood will vibrate quite a bit without any direct coupling at all.
 
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MattHooper

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You could be right. I'm envisioning an experiment involving a large plywood board and a speaker. What I'm thinking of doing is suspending the speaker just 1/4" in front of the plywood, and then solidly connecting the speaker to the plywood, and then using spring loading between the plywood and the speaker. What I'm interested in hearing is how much audible vibration is coming off the cabinet, and how much more audible can I make it by directly coupling the speaker to the plywood. Also, how much can I get the plywood to vibrate without the speaker even touching it at all. My past experience is that the plywood will vibrate quite a bit without any direct coupling at all.

As I believe I mentioned earlier, I tried two types of spring decoupling products beneath my floor standing speakers (on a sprung wood floor) and I
found the sound changed in a way I didn't care for. I lost some "feel" of the music - the sound became a bit more electrostatic-like.
 

Tim Link

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As I believe I mentioned earlier, I tried two types of spring decoupling products beneath my floor standing speakers (on a sprung wood floor) and I
found the sound changed in a way I didn't care for. I lost some "feel" of the music - the sound became a bit more electrostatic-like.
Yes, I read that shortly before I posted. I thought I read you wished you could get the best of both worlds and I was postulating that maybe it is possible by not suspending the speakers but suspending other things in the room to do to the floor what the speakers were doing. It makes sense to me that decoupling the speaker could have some bad effects. If the speaker cabinet does tend to vibrate significantly, then suspending it loosely will only make it vibrate even more, although this could depend on a number of factors. Ideally it would be coupled to a very dense, stiff immovable object that would refuse to vibrate and pin the speaker down so it couldn't vibrate either.
 
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MattHooper

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Yes, I read that shortly before I posted. I thought I read you wished you could get the best of both worlds and I was postulating that maybe it is possible by not suspending the speakers but suspending other things in the room to do to the floor what the speakers were doing. It makes sense to me that decoupling the speaker could have some bad effects. If the speaker cabinet does tend to vibrate significantly, then suspending it loosely will only make it vibrate even more, although this could depend on a number of factors. Ideally it would be coupled to a very dense, stiff immovable object that would refuse to vibrate and pin the speaker down so it couldn't vibrate either.

I didn't really get back to this thread to say:

I did my best to get some sort of compromise, really throwing spaghetti at the wall to see if anything stuck.

So I had the Townshend speaker bars with the spring footer isolation, the cheaper spring footers I described in the first post, and also some Isoacoustic isolation pucks (left over from trying them for my turntable isolation).

I tried every combo I could think of: Townshend bars only under the front or the backs of the speakers (getting some isolation, but also some contact to the floor), same with the spring footers, combos of the Townshend and other spring footers, the iso pucks, combos between all of them. Nothing ever sounded as good to my ears as the speakers simply resting on the floor (on the rug), no spikes or nuthin'.
 

Tim Link

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I didn't really get back to this thread to say:

I did my best to get some sort of compromise, really throwing spaghetti at the wall to see if anything stuck.

So I had the Townshend speaker bars with the spring footer isolation, the cheaper spring footers I described in the first post, and also some Isoacoustic isolation pucks (left over from trying them for my turntable isolation).

I tried every combo I could think of: Townshend bars only under the front or the backs of the speakers (getting some isolation, but also some contact to the floor), same with the spring footers, combos of the Townshend and other spring footers, the iso pucks, combos between all of them. Nothing ever sounded as good to my ears as the speakers simply resting on the floor (on the rug), no spikes or nuthin'.
Nobody can say you didn't try it!
 

Frank Dernie

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You could be right. I'm envisioning an experiment involving a large plywood board and a speaker. What I'm thinking of doing is suspending the speaker just 1/4" in front of the plywood, and then solidly connecting the speaker to the plywood, and then using spring loading between the plywood and the speaker. What I'm interested in hearing is how much audible vibration is coming off the cabinet, and how much more audible can I make it by directly coupling the speaker to the plywood. Also, how much can I get the plywood to vibrate without the speaker even touching it at all. My past experience is that the plywood will vibrate quite a bit without any direct coupling at all.
The size of the board will dictate both the frequencies it will radiate most strongly and how loud.
The speaker design consultant I know predicts the cabinet radiation using finite element methods since it is impossible to separate from the drive unit output on its own from the measurement.

Have fun but I don't think you will add to the knowledge of physics already extant!
 

Tim Link

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The size of the board will dictate both the frequencies it will radiate most strongly and how loud.
The speaker design consultant I know predicts the cabinet radiation using finite element methods since it is impossible to separate from the drive unit output on its own from the measurement.

Have fun but I don't think you will add to the knowledge of physics already extant!
Yeah, I don't expect to add to physics. In specific situations those of us who aren't sure about things can learn from a demonstration. What's being claimed is that cabinet vibrations being transmitted into the floor create audible issues in rooms. I'm not convinced that most decent speaker cabinets vibrate enough for that to be an issue. I am convinced that airborne sound does stimulate building surfaces to significant vibration, and I know that those surfaces can be damped to minimize the problem.
 

Chromatischism

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What's being claimed is that cabinet vibrations being transmitted into the floor create audible issues in rooms. I'm not convinced that most decent speaker cabinets vibrate enough for that to be an issue.
Not necessarily audible, but tactile. Our senses combine them for enjoyment.
 

Thomas_A

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Yeah, I don't expect to add to physics. In specific situations those of us who aren't sure about things can learn from a demonstration. What's being claimed is that cabinet vibrations being transmitted into the floor create audible issues in rooms. I'm not convinced that most decent speaker cabinets vibrate enough for that to be an issue. I am convinced that airborne sound does stimulate building surfaces to significant vibration, and I know that those surfaces can be damped to minimize the problem.

A loudspeaker may well transmit vibrations that can be audible depending on the surface that the speaker sits, as shown in this thread.
 

Tim Link

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A loudspeaker may well transmit vibrations that can be audible depending on the surface that the speaker sits, as shown in this thread.
Yes but how is it transmitted? I am arguing that it's through the air. Even if you decouple the speaker from the floor with suspension, the air column is still connecting the speaker to the floor, and the speaker's job is to vibrate the air column, which it does very effectively. This in turn vibrates the floor. I'm arguing that speaker cabinets don't transmit nearly as much energy into the floor as the driver does through the air. However, a suspended speaker on the floor could act as an effective floor damper under the right conditions, calming the floor down and improving the sound in the room.
 

Tim Link

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The cabinet vibrates. Ever touched a subwoofer while it's operating?

Newton's Third Law.
The cabinet definitely vibrates. But how much? Besides Newton's third law there's cabinet flex that could cause vibrations. If you're pumping hundreds of watts into a relatively inefficient sub with a lightweight, flexible cabinet, and a heavy, stiff small diameter long throw woofer cone, I could see cabinet vibration becoming a real serious problem. I would get a more efficient subwoofer with an adequately massive and stiff cabinet.
 

Thomas_A

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Yes but how is it transmitted? I am arguing that it's through the air. Even if you decouple the speaker from the floor with suspension, the air column is still connecting the speaker to the floor, and the speaker's job is to vibrate the air column, which it does very effectively. This in turn vibrates the floor. I'm arguing that speaker cabinets don't transmit nearly as much energy into the floor as the driver does through the air. However, a suspended speaker on the floor could act as an effective floor damper under the right conditions, calming the floor down and improving the sound in the room.

Air is also transmitting especially you can see vibration at frequencies of standing waves in the room.

However vibration can be mechanically transmitted and give rise to measurable and audible distortion, as shown. It is nothing new, just physics.

So why risk add distortion to the system when it can be easily avoided?
 

Tim Link

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Air is also transmitting especially you can see vibration at frequencies of standing waves in the room.

However vibration can be mechanically transmitted and give rise to measurable and audible distortion, as shown. It is nothing new, just physics.

So why risk add distortion to the system when it can be easily avoided?
The OP says in the end, after trying various isolation methods and spikes, he found it sounded best if the speakers were simply placed on the floor. Hard to say why but I suspect what's happening with a suspended speaker is complicated by various factors that may sometimes lead to worse results. I'm speculating about what might be going on. If the floor is resonating at certain frequencies due to airborne sound stimulation, which I would bet is causing far more audible effects than solid mechanical transmission in the majority of cases, that will be changed somewhat by putting heavy things like speakers, equipment racks, and furniture on the floor. And if those things are suspended in various ways that will have further effects. It may just end up shifting the primary resonance to different frequencies and different parts of the floor, which would explain why it sometimes sounds better and other times doesn't.
 
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