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Do speakers need to be fixed in place?

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#1
My bookshelf speakers sit on top of a solid TV console, with their front sticking out the edge of the console to at least somewhat mitigate early reflections from the console top. They are not fixed in their place and with enough force you could slide them in any direction. They weigh about 30 lbs each. I don't hear any noise, rumble, or resonances from the speakers or the furniture. Should I expect to notice any improvement in sound by somehow anchoring them in place? The internet is full of anecdotes of "night and day" differences thanks to this or that method. But I would much rather learn of an analytic argument for or against it.

What prompted this inquiry is that the other day I read about using Blu Tack underneath the speakers. Since I had some Blu Tack lying around I figured I would give it a shot. To my surprise there was a marked improvement in the lower frequencies. Fearing the potential damage from long term use of Blu Tack, I had to remove it, after which I perceive that the improvement in the lower frequencies has disappeared. However, confounding this was that to mount the Blu Tack, I had to move the speakers, and then redo the measurement and bass management (DSP). So I don't know to which of the factors to attribute the effect: rearrangement, different EQ, or subjective bias.

As a last resort I could of course repeat the experiment, then again, instead of reinventing the wheel I feel I should rely on the knowledge and experience of the experts here. So I'm all ears :)
 
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#2
Two potential problems I see with your current setup: 1. as you wrote vibrations from the speaker case can move to the tv console they are sitting on. This can negatively affect the sound. The sound produced by a loudspeaker is the result of a vibrating membrane. To reproduce the music signal as exactly as possible nothing else but the membrane should be vibrating. That's why you want to decouple your speakers from your tv console. Blu Tack is one way to achieve it. But there are a lot of other options. Use some of these, for example:

https://www.amazon.com/slp/speaker-isolation/7owoepg9ptyc7hb

As you thought you heard an improvement when the speakers were decoupled with Blu Tack, it will be a good idea to have them permanently isolated from the console.

2. Apart from the decoupling issue, there is also speaker placement to consider. If the speakers move (if they vibrate they will move over time), this will change the sound to some degree (depening on your room, your listening spot etc.). The effect of which could be heightened through the fact that you are using room correction eq. If the speakers are not in the same place where you took the measurement, your correcting eq will not be accurate anymore.

All in all decoupling your speakers is an easy recommendation in your case. It's simple, it doesn't cost much, it's set and forget. How much of a difference it makes depends on a lot of variables. I'd recommend it anyway. It won't do any harm. And as you have heard a difference with Blu Tack, chances are that it will make an audible difference in your case.
 
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#3
Two potential problems I see with your current setup: 1. as you wrote vibrations from the speaker case can move to the tv console they are sitting on. This can negatively affect the sound. The sound produced by a loudspeaker is the result of a vibrating membrane. To reproduce the music signal as exactly as possible nothing else but the membrane should be vibrating. That's why you want to decouple your speakers from your tv console. Blu Tack is one way to achieve it. But there are a lot of other options. Use some of these, for example:

https://www.amazon.com/slp/speaker-isolation/7owoepg9ptyc7hb

As you thought you heard an improvement when the speakers were decoupled with Blu Tack, it will be a good idea to have them permanently isolated from the console.

2. Apart from the decoupling issue, there is also speaker placement to consider. If the speakers move (if they vibrate they will move over time), this will change the sound to some degree (depening on your room, your listening spot etc.). The effect of which could be heightened through the fact that you are using room correction eq. If the speakers are not in the same place where you took the measurement, your correcting eq will not be accurate anymore.

All in all decoupling your speakers is an easy recommendation in your case. It's simple, it doesn't cost much, it's set and forget. How much of a difference it makes depends on a lot of variables. I'd recommend it anyway. It won't do any harm. And as you have heard a difference with Blu Tack, chances are that it will make an audible difference in your case.
That makes sense. Decoupling the speakers doesn't seem to do any harm, but that still doesn't address my original question: should such isolation fix the speakers in place? You could have decoupled speakers that can move around freely. Are there any sonic benefits to blocking this movement, little as it may be?
 

BillG

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#4
At 30 pounds each, those speakers won't vibrate on their own and will be fixed in place under all but the most extreme of circumstances. I would suggest decoupling them from the the console though - as you've noticed, this improves the bass - with any number of stands from the inexpensive foam ones to the more expensive metal.
 

March Audio

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#5
That makes sense. Decoupling the speakers doesn't seem to do any harm, but that still doesn't address my original question: should such isolation fix the speakers in place? You could have decoupled speakers that can move around freely. Are there any sonic benefits to blocking this movement, little as it may be?
Its a big subject but contrary to popular belief even if you fix the speaker cabinet rigidly to a supporting surface with the view to stopping it moving, you wont actually stop the cabinet (baffle) vibrating and moving.

From a vibration perspective you can think of a structure being made up of discrete elements which will carry on doing their own thing when a vibration stimulus is applied (dependent upon the basics of mass, stiffness and damping). Yes the vibration characteristics will change if an object is secured at one or more ends, but you fundamentally will not stop it vibrating by doing so.

As an extreme example go to the cupboard and grab a wine glass. Hold it very loosely by the base in your hand. Flick the bowl. It will go ding and ring for a period of time. Now take the glass and hold it again by the base as tight and hard as you can against a very solid surface, ie stone kitchen benchtop or concrete floor. Flick the bowl again. Guess what, it vibrates and rings almost in an identical way to when it was not secured. :)

However if the speaker is making your TV cabinet vibrate and make audible noise, then you may well want to decouple the two.
 
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RayDunzl

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#6

March Audio

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#7
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Its a big subject but contrary to popular belief even if you fix the speaker cabinet rigidly to a supporting surface with the view to stopping it moving, you wont actually stop the cabinet (baffle) vibrating and moving.

From a vibration perspective you can think of a structure being made up of discrete elements which will carry on doing their own thing when a vibration stimulus is applied (dependent upon the basics of mass, stiffness and damping). Yes the vibration characteristics will change if an object is secured at one or more ends, but you fundamentally will not stop it vibrating by doing so.

As an extreme example go to the cupboard and grab a wine glass. Hold it very loosely by the base in your hand. Flick the bowl. It will go ding and ring for a period of time. Now take the glass and hold it again by the base as tight and hard as you can against a very solid surface, ie stone kitchen benchtop or concrete floor. Flick the bowl again. Guess what, it vibrates and rings almost in an identical way to when it was not secured. :)

However if the speaker is making your TV cabinet vibrate and make audible noise, then you may well want to decouple the two.
Thank you, that's helpful.
 
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#9
At 30 pounds each, those speakers won't vibrate on their own and will be fixed in place under all but the most extreme of circumstances. I would suggest decoupling them from the the console though - as you've noticed, this improves the bass - with any number of stands from the inexpensive foam ones to the more expensive metal.
You're right. I cannot detect any vibration or movement. Thanks for the suggestion.
 

Shadrach

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#11
My bookshelf speakers sit on top of a solid TV console, with their front sticking out the edge of the console to at least somewhat mitigate early reflections from the console top. They are not fixed in their place and with enough force you could slide them in any direction. They weigh about 30 lbs each. I don't hear any noise, rumble, or resonances from the speakers or the furniture. Should I expect to notice any improvement in sound by somehow anchoring them in place? The internet is full of anecdotes of "night and day" differences thanks to this or that method. But I would much rather learn of an analytic argument for or against it.

What prompted this inquiry is that the other day I read about using Blu Tack underneath the speakers. Since I had some Blu Tack lying around I figured I would give it a shot. To my surprise there was a marked improvement in the lower frequencies. Fearing the potential damage from long term use of Blu Tack, I had to remove it, after which I perceive that the improvement in the lower frequencies has disappeared. However, confounding this was that to mount the Blu Tack, I had to move the speakers, and then redo the measurement and bass management (DSP). So I don't know to which of the factors to attribute the effect: rearrangement, different EQ, or subjective bias.

As a last resort I could of course repeat the experiment, then again, instead of reinventing the wheel I feel I should rely on the knowledge and experience of the experts here. So I'm all ears :)
It depends on what you are fixing them to.
You can attampt to isolated a source of vibration, or you can provide a sink for the energy to an object, usually high mass.
 

RayDunzl

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#12
OMG I like it but can you imagine the frequency response peak at resonance !
Maybe it includes a notch filter for the Memorex Lady...

1557759559859.png
 

RayDunzl

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#13
There was a guy in Vienna that played the entire Toccata and Fugue in D minor on wine glasses.
I wonder what he uses to stick his glasses to the table?

Or is he just so skilled with his touch he doesn't need to?

 
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#14
I wonder what he uses to stick his glasses to the table?

Or is he just so skilled with his touch he doesn't need to?

I saw him in 2001. If I remember correctly the glasses weren't stuck to the board. For different tunings he would swap them out for smaller or larger glasses.
Maybe I should track him down and ask his take on affixing the sound source to a rigid body ;)
 

RayDunzl

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#16

RayDunzl

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#18
Does it follow that they should also be fixed in person, then?
I would much prefer to fix anything myself than engage a repairman.

Even @restorer-john , not because I think him inept, but I have this idea he keeps everything he worked on that he liked in his antique gear dungeon.

customer: Can you fix this? I really like it.
Restorer-John: I'll take a look at it, no charge.
customer; Great! Thanks!
time passes
customer: Whats happening, John?
Restorer-John: It can't be repaired. Doesn't work at all. The defect spread to the rest of the unit. None of the parts are manufactured anymore. It's toast. Had to throw it out, stunk up the house. Nearly killed my dingo. Sorry. But... no charge!
customer: Thanks for trying.
Restorer-John: You're welcome. Tell your friends!
 
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restorer-john

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#19
but I have this idea he keeps everything he worked on in his antique gear dungeon.
That's funny, but kind of true. I taken in so many strays and given them a new life. My best friend kept bringing me stuff to 'play with' or 'use for parts', so much so, I have banned the practice. I only do repairs for family and friends and established audiophile friends who keep buying vintage gear. It's too much otherwise.

I've had people ship stuff from the US and Europe on the understanding it will take as long as it takes and cost as much as it takes, but it will be perfect. Shipping costs have gone sky high in the last several years, so I'm glad in a way. There was always a great risk of transit damage.

Not sure what the future holds. I may have to empty the store rooms in the medium term, the ongoing cost is crazy. But it's a case of the sheer scale of the collection- I roll up the doors, look at the floor to ceiling boxes and shiver, roll it back down and walk away.

I recently came across the receipt for some of the parts I needed to fix this amplifier (The Lux L-81):

https://www.audiosciencereview.com/...eed-to-be-sustainable.6330/page-3#post-141124

1557783830146.jpeg
 
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DKT88

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#20
As a last resort I could of course repeat the experiment, then again, instead of reinventing the wheel I feel I should rely on the knowledge and experience of the experts here. So I'm all ears :)
Some reviewers check speaker cabinets for resonance with a stethoscope. You could use one to check the console. You can get one at Amazon for $12. I'm not sure it works though, I would like to know if someone here has tried it.
 

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