Theory Behind Speaker Stand Design

[shkumar4963]

There are conflictig theories regarding Speaker Stand design and use. In this thread we would like to capture many of them and how they impact actual performance that we can all hear.

Do we want coupling between the standmount and stand or not? How do we achieve that? Why it works for some speakers with no coupling between stand and speaker while for others strong coupling (thorugh tape or bolt) is recommended? How does this impact Bass performance of a speaker and why?

Do we want strong coupling between stand and ground or not? What kind of coupling is achived with spikes at the bottom? Is that good for wooden floors as well as concrete floors?

How heavy should the speaker stand be? How and why does it impactr Bass performance of a speaker?

 

[matt49]

With all due respect to other members of the forum (and in particular CJSF, who knows a thing or two about stands), I doubt you're likely to generate the kind of technical discussion you want on this forum.

I'm sure plenty of people have views about the structure of stands (solid, hollow, open frame) and whether they're coupled to or isolated from the floor, but I don't think people's knowledge will extend much beyond their own experience.

You might get a more technically informed discussion over on the PFM forum.

*shok*

Matt

 

[Thompsonuxb]

It's almost Xmas, surely there is room for friendly debate amongst colleagues.

A speaker generates sound, vibration not just from the drivers but from the whole enclosure.

Some boxes use materials that resonate at a given frequency - If suspended in mid air this is more apparent - which augment the bass frequencies from the driver. Ports make use of the low frequencies emitted from the rear of the cone to do the same.

A speaker stand isolates/transfers the sound from a speaker box by absorbing the sound resonating from the box.

If coupled to the floor this will have the same effect as a tuning fork - depending on floor type results will differ.

For example hit a tuning fork and hold it in mid air will give you a different response if compared to placing the base of the tunning fork on a hard surface.

Fixed rigidly to the stand resonance is transferred from the speaker box so mostly what the cones are doing is heard, without the 'coloration' of the box itself.

If on a hard surface this will give a 'leaner' bass response compared to a suspended wooden floor were those frequencies will again be transferred via the stands.

The composition of the stands is important as is their solidity which has a bearing on bass performance again like a tuning fork.

The laws of physics and the transfer of energy explains it. That's the theory anyway.

With all due respect to other members of the forum (and in particular CJSF, who knows a thing or two about stands), I doubt you're likely to generate the kind of technical discussion you want on this forum.

I'm sure plenty of people have views about the structure of stands (solid, hollow, open frame) and whether they're coupled to or isolated from the floor, but I don't think people's knowledge will extend much beyond their own experience.

You might get a more technically informed discussion over on the PFM forum.

*shok*

Matt

 

[Reijer]

Nice tread.

I have these: http://www.vmacoustics.dk/index4.html

Not filled them, just use them as they were delivered. One thing only: put some antiscratch filt under the coasters so that I can slide them back and forth over the floor.

Sounds nice to me!

 

[CJSF]

Back in the good old days, (70's-80's) I developed a stand systm that rather shook the hifi world, few beleving, however with time, most saw the light. We did many demos, a few blind, along with the normal dealer type. Many of the stands you see today are a direct result of those early 'Foundation' designs and are still relevent, few are parted with, if you find a pair of 'Foundatrion Designer' stands, grab them. Foundation Audio made the elegant single stem stand work, prior to this most so called 'rigid stands' were cumbersome, oil deric style, made from 25mm sq stock, filling was never even considered, relying on an over size base for stability. Thick carpet made them rock about especialy when fitted with castors!

John Michell made a break through with the very simple 6mm spike, it was not for isolation or energy transfer as many think but the way to get through said thick carpet to give a solid adjustable footing to the stand. In fact modern solid wood type floors would benefit the stand on adjustable round ended bolts insted of a spike. John also came up with the inverted spike, stand to speaker type, not a good idea in my humble opinion, small, very small blobs of BlueTac are far superior.

The system I came up with has been the subject of much conjecture, 'how', copying and claims, in my experiance is they mostly fall short.

I spent many hours experimenting over many years, to come up with the best solution, this evolved to a point where the mix we used became alost universal. The same formula was able to be used in the single stem 'Classic', the twin stem 'Pie' and the ultimate 4 verticals 'Designer', the formula was simply split by 2 or 4.

Believe me, 'formula' was the word, verious grain sizes of the diferent materials were tried, it took a long time. We had listening sessions around the trade. So getting it right is not the bung the stands in the corner and fill with any old stuff.

I have neaver reveiled the full formula or method, people have tried emptying my stands, this simply mixes it all up.

These days, the best DIY home results are fill with kiln dried sand, (thats the stuff used for block paving fill) 1/4, 1/2, 3/4 and full, see which sounds best in your room with your chosen speaker. Base is still a little wanting compare with the original Foundation designs but they are usualy better than no filling.

CJSF

 

[chebby]

I have neaver reveiled the full formula or method, people have tried emptying my stands, this simply mixes it all up.

So a 'core sample' of the filling would be better?

 

[CJSF]

I have neaver reveiled the full formula or method, people have tried emptying my stands, this simply mixes it all up.

So a 'core sample' of the filling would be better?

If someone was that desperate, I supose so? Proveing the point, just how good the 'Foundation' product was and still is if you have a pair?

CJSF

 

[CJSF]

There is also the issue of the finish, not your odinary powder coate, which was part of the sound. The welding was of the highest standard (Lloyds quality, my Dad did not know how to do a bad weld) and every stand was hand finished equaly to a finish that the operatives took pride in, Rolls Roys quality in speaker stand terms.

 

[chebby]

Proveing the point, just how good the 'Foundation' product was and still is if you have a pair?

Nah. I would have to reinforce the floor to support the 'Designers'.

No disrespect to your award winning products, but I find most speaker stands ugly, ungainly and reminiscent of miniature North Sea oil platforms!

 

[Vladimir]

Did you guys measure vibration on the stands and speakers with an accelerometer or was it just sighted listening experiments?

I experimented just by listening and touching surfaces to detect vibration. I had situations when more distortion due to uncontrolled vibration and speakers slightly rocking sounded more appealing and a better setup and more accurate sound sounded dull and took getting used to.

Cheers

 

[davedotco]

Some years ago, as a shop we got bored with all the different stands that we were using for dems, at the time we had nearly a dozen pairs.

So we contacted our good friends at Slate Audio and had him built two pairs of stands, 24 inch with a small top plate and 16 inch with a much larger top plate. The idea was that we could dem everything on these stands as a sort of reference.

The single most interesting result of this change was that our speaker sales changed dramatically, our best selling speaker was the Epos ES14. After the change sales virtually dried up, it took us a month or so to really notice, but people simply stopped buying them, odd when you considered that the Slate stand was far more elegant than the open frame, oil derrick style of their own dedicated stand.

I can't quite remember why, but we did a dem with their 'proper' stands, straight away we heard the difference, changing back to the Slate stands proved it. The beautifully build Slate stands made the speakers sound slow and ploddy, the wonderful articulation and, dare I say speed, just dissappeared.

Surprisingly we hadn't noticed, but our customers had, and voted with their wallets.....!

 

[iQ Speakers]

I appear to have replyed to the other thread with the same title!!

 

[CJSF]

No we did not ever get into measurements, I believed, still do, my ears are what I listen with, they are the instuments that tell me if something is right or not.

We new about what slate did very early on, not that we heard it, the grapvine filtered back. They look OK, but that was where it stoped? One of the classic mistakes is taking to much energy out of the cabinet, the sound goes so flat, a little bit of destortion is a good thing,*smile*

The single stem 'Foundation Classic' was the stand to sell to the 'stands are ugly' customer. Even the designes were made by eye, drawn up on paper first, a set of parts were cut, painted black, then put together dry. Its suprising how a quater inch more or less space in what ever direction makes a visual differeance. This dry blank was measured and noted on the drawing, then wellded up, checked sonicaly, then and only then was the gig made. I suppose with computers these days this faffing about may not be required, but it always felt right, there was part of me, my Father, even the guys in the factory were encuraged to give an opinion, usualy at break time, if a new design/size was on the bench, a cupatea and a sarni can be inspiring.

One of the commonest mistaked made by multi stem stand designers today, they put the verticals far to close to the edge of the speaker making it look as you say Chebby, like an oil instalation, oil instalations dont have to look prietty. I saw this the other day, a well known manufaturers speaker/stand combination, the proximity of the verticals to the edge of the speakers made it look like R2 in star wars, great speaker, terible looks.

CJSF

 

[Reijer]

Did you guys measure vibration on the stands and speakers with an accelerometer or was it just sighted listening experiments?

I experimented just by listening and touching surfaces to detect vibration. I had situations when more distortion due to uncontrolled vibration and speakers slightly rocking sounded more appealing and a better setup and more accurate sound sounded dull and took getting used to.

Cheers

No, not with an accelerometer. I put my hands on the stands and speakers when Smaug was talking and do his tricks under the mountain in the second Hobbit movie. I felt no vibration in the stands and some in the speakers. The speakers stands on 4 rubber domes on the topplate of the stand.

 

[shkumar4963]

Thank you CJSF for a dealer explanation. Unfortunately since I am new to stands, I dis not understand many terms. Please suggest additional readings that will familiarize me with these terms and associated concepts.

I have had floor standing speakers all my life and bought my first pair of LS50 just recently.

Many reviewers and many FM strongly suggested that the speakers will not sound good without the stands. And that got me thinking as to why stands should make such a difference.

Based on my high school physics, here are some ameturish reasons I can think of.

1. Stands are needed to increase the weight of the speaker box so that it does not move during cones motion. With this reasoning, placing or bolting the speakers to a heavy slab should work better.

On the other hand hanging the speakers with a rope or two will be the worst.

The effect will be most noticeable with light speaker boxes than heavier ones.

The effect will be more applicable when playing at higher volumes than lower.

Also with this reasoning heavy coupling or bolting to a cement floor will be the best as it provides the best support to the box.

2. Placing speakers on anything induces vibrations in that structure and that colors the sound. Low vibrating stands are thus better.

With this reasoning, hanging speakers will be better than placing them on stands and Inverted spikes will be better than blue tac.

3. Stand provided damping to the speaker box that otherwise vibrate at their resonance frequency. With this logic a viscoelastic seal between the stand and the speakers will be the best.

I can see how the first reasoning may improve the bass

 

[chebby]

Thank you CJSF for a dealer explanation.

CJ was the designer and manufacturer of his own range of (award winning) products, not a dealer.

 

[shkumar4963]

Thank you CJSF for a detailed explanation. Unfortunately since I am new to stands, I did not understand many terms. Please suggest additional readings that will familiarize me with these terms and associated concepts.

I have had floor standing speakers all my life and bought my first pair of LS50 just recently.

Many reviewers and many FM strongly suggested that the speakers will not sound good without "good" stands. And that got me thinking as to why stands should make such a large difference. Most reported much improved bass.

Based on my high school physics, here are some ameturish reasons I can think of for why stands should impact the sound quality.

1. Stands are needed to increase the weight of the speaker box so that it does not move during the cone motion, especially at bass frequencies. With this reasoning, placing or bolting the speakers to a heavy slab should work better.

On the other hand hanging the speakers with a rope or two will be the worst.

The effect will be most noticeable with light speaker boxes than heavier ones and while playing at higher volumes.

Also with this reasoning heavy coupling or bolting to a cement floor will be the best as it provides the best support to the box.

2. Placing speakers on anything induces vibrations in that structure and that colors the sound. Low vibrating stands are thus better.

With this reasoning, hanging speakers will be better than placing them on stands and Inverted spikes will be better than blue tac.

3. Stand provided damping to the speaker box that otherwise vibrate at their resonance frequency. With this logic a viscoelastic seal between the stand and the speakers will be the best to absorb speaker box vibrations.

I can see how the first reasoning may improve the bass performance and the other two reasoning may reduce sound coloration.

I see many professional speakers in concerts mounted on top of light stands. Why is that since they generally play at very loud volumes. I don't see any spikes there either.

Also heavier the stand, better it should be. But CJSF reported that filling the speaker stand half way may be better than filling it completely.

Coupling stands with square pads or bolts to cement flour and bolting speakers to the stand should be better than spikes or blue tac with this reasoning. But most stands recommend spikes. Why?

Does the reasonings make sense?

Are there other affects that I am not taking into account?

 

[shkumar4963]

Thank you CJSF for a dealer explanation.

CJ was the designer and manufacturer of his own range of (award winning) products, not a dealer.

Sorry. Typo. I meant "detailed".

 

[shkumar4963]

It's almost Xmas, surely there is room for friendly debate amongst colleagues.

A speaker generates sound, vibration not just from the drivers but from the whole enclosure.

Some boxes use materials that resonate at a given frequency - If suspended in mid air this is more apparent - which augment the bass frequencies from the driver. Ports make use of the low frequencies emitted from the rear of the cone to do the same.

A speaker stand isolates/transfers the sound from a speaker box by absorbing the sound resonating from the box.

If coupled to the floor this will have the same effect as a tuning fork - depending on floor type results will differ.

For example hit a tuning fork and hold it in mid air will give you a different response if compared to placing the base of the tunning fork on a hard surface.

Fixed rigidly to the stand resonance is transferred from the speaker box so mostly what the cones are doing is heard, without the 'coloration' of the box itself.

If on a hard surface this will give a 'leaner' bass response compared to a suspended wooden floor were those frequencies will again be transferred via the stands.

The composition of the stands is important as is their solidity which has a bearing on bass performance again like a tuning fork.

The laws of physics and the transfer of energy explains it. That's the theory anyway.

With all due respect to other members of the forum (and in particular CJSF, who knows a thing or two about stands), I doubt you're likely to generate the kind of technical discussion you want on this forum.

I'm sure plenty of people have views about the structure of stands (solid, hollow, open frame) and whether they're coupled to or isolated from the floor, but I don't think people's knowledge will extend much beyond their own experience.

You might get a more technically informed discussion over on the PFM forum.

*shok*

Matt

Matt... what is PFM forum. Please provide additional details.

 

[shkumar4963]

Good explanation...

Should i conclude the following from your explanation:

1. For speaker cabinets that are sturdier and don't vibrate as much, stands will have less impact.

2. Speakers solidly bolted on stands that are bolted to the concrete below will be best for bass performance.

3. Would bolting a shelf on the wall and putting speakers on them will have the same effect?

4. Speakers should be solidly mounted on the stands. The stand should be decoupled from the suspended wooden floor below. Does spikes at the bottom of the stand provide this decoupling? Or do they couple it further?

5. What is the purpose of speaker spikes provided on top of the stand to place the speaker on? What situation will they be helpful?

6. What are the purpose of rubber spacers provided on top of the stand for speaker placement? What situation will they be helpful?

7. In your personal experience, did stand make any difference in overall sound quality? I am asking because I have tried all permutation and combinations but with little or no impact on overall sound quality.

 

[ID.]

Matt... what is PFM forum. Please provide additional details.

Pink Fish Media

http://www.pinkfishmedia.net/forum/

 

[CnoEvil]

Good explanation...

Should i conclude the following from your explanation:

1. For speaker cabinets that are sturdier and don't vibrate as much, stands will have less impact.

2. Speakers solidly bolted on stands that are bolted to the concrete below will be best for bass performance.

3. Would bolting a shelf on the wall and putting speakers on them will have the same effect?

4. Speakers should be solidly mounted on the stands. The stand should be decoupled from the suspended wooden floor below. Does spikes at the bottom of the stand provide this decoupling? Or do they couple it further?

5. What is the purpose of speaker spikes provided on top of the stand to place the speaker on? What situation will they be helpful?

6. What are the purpose of rubber spacers provided on top of the stand for speaker placement? What situation will they be helpful?

7. In your personal experience, did stand make any difference in overall sound quality? I am asking because I have tried all permutation and combinations but with little or no impact on overall sound quality.

I'm not Mr UXB, but here are my thoughts:

1. I have found all Standmounts that I've come across need good stands....some work better with light stands, some heavy. The amount and type of filling also has an effect.

2. A speaker and its Stand should (imo) be considered as a single unit that works in unison.....so bolting the speaker to the stand is a good idea. Making a very stable connection between Stand and floor ensures there is little fore and aft movement.

3. I don't think this would work as well.

4. IME. Spikes do not decouple, quite the opposide in fact. They are there to dig into the floor to give stability.

5. Spikes on the top hold the speaker stable and give a certain amount of coupling to the stand....but they can damage the underside of your speaker.

6. If I understand you right, you are talking about a rubber type material (including Blu-Tak) between the Speaker and the Stand....this is for decoupling the speaker from the stand, which is useful if you don't want to transmit energy from the speaker through the stand and into a suspended wooden floor.

7. IME. Getting the right Stand (ie. Metal/Wood/Light/Heavy) and experimenting with types/amount of filling is vital in getting the most out of a pair of Standmounts.....you can use Sand/Rice/Cat Litter/Lead Shot/Atabites. Some add mass (Atabites), some are good for damping (Rice) and some do both (Sand). Overfilling the Stands can rob the life from some speakers; underfilling can leave the Bass lacking definition.

I am quite happy to be corrected by the more knowledgeable on here, but this is my experience/understanding.