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lost with monitor stands

Postby Bob Moose » Tue Feb 12, 2013 7:15 pm

Hello,

I need good stands for KH O300 monitors.

The floor does not look springy (concrete + either hollow or solid bricks). It is covered with a crappy tiled floor so I will put some linoleum on it.

The most important thing is damping the low frequency vibrations properly.
I have no idea if it is better to have a very heavy stand that damps all vibrations before they go to the floor, or a stand that propagates all vibrations into the floor and then the floor acts as a damper.

KH have many mounting accessories (the monitors can be screwed on a plate, for example) but they do not make a stand themselves, so they recommend the expensive K&M 26795 stand:
http://produkte.k-m.de/en/Speakerlighting-and-monitor-stands-and-holders/Monitor-stands/26795-DESIGN-MONITOR-STAND-structured-black

But is it heavy enough to damp all vibrations? If it does, why not, but it's still about 600 euros for 2 stands + 2 plates.

K&M also make less expensive stands that are still compatible with the KH accessories, but they are much lighter.

Finally, I could make DIY wood/sand column stands, but not sure if the O300 are heavy enough for just putting them on the top.

What would you do?

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Re: lost with monitor stands

Postby fay spook » Wed Feb 13, 2013 9:27 am

From the look of the stands they are a fairly light weight (non-rigid) pole with heavy tops and bottoms. Effectively these are light stands with the bottom end plates acting as a small "floor". If the top plate is too heavy it will stop the cabinet vibrations going down the stand because the vibrations take the easiest path and a big heavy top plate is harder to pass through than a light one. From this you can also get a reflection back into the cabinet. By the time any vibration has passed down a stand, losing energy all the way there isnt much for a stand end plate to deal with. All these are pretty low energy levels but the KHs are good monitors and it would be good to get the absolute best out of them.

Have a look at the lighter stands and dont pay for expensive end plates when you have a floor that does the same job for nothing. Some nice sharp spikes going into the floor will help too.
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Re: lost with monitor stands

Postby Bob Moose » Mon Feb 18, 2013 11:40 am

Thanks for your answer

fay spook wrote:From the look of the stands they are a fairly light weight (non-rigid) pole with heavy tops and bottoms. Effectively these are light stands with the bottom end plates acting as a small "floor". If the top plate is too heavy it will stop the cabinet vibrations going down the stand because the vibrations take the easiest path and a big heavy top plate is harder to pass through than a light one. From this you can also get a reflection back into the cabinet.
The top plate weights 3.3 kg:
http://www.neumann-kh-line.com/klein-hummel/globals.nsf/resources/neumann_lh41_mounting_manual_1212_en.pdf/$File/neumann_lh41_mounting_manual_1212_en.pdf

It's not a K&M plate, it is made by Neumann / Klein+Hummel and it can be installed on many different stands. Is it too heavy? The base plate must be screwed to the loudspeaker.

Here you can see a mounting example with the O300 and the aforementioned K&M stand (left picture):
http://www.neumann-kh-line.com/neumann-kh/home_en.nsf/HTMLProduct?ReadForm&path=prof-monitoring&accid=2A86AA5A7CFA9E96C12573480063DA01#

By the time any vibration has passed down a stand, losing energy all the way there isnt much for a stand end plate to deal with. All these are pretty low energy levels but the KHs are good monitors and it would be good to get the absolute best out of them.
Which kind of stand would you recommend then? Concrete blocks, wooden column filled with sand, or something like this?
This is a small studio, but we have a great acoustic treatment and it is pointless to get such speakers if the stand makes the bass response inaccurate or smears the transient precision.

Have a look at the lighter stands and dont pay for expensive end plates when you have a floor that does the same job for nothing.
I have the cheapest triangle-based Millenium/Thomann stands currently, I have used them with small monitor speakers in my former studio but I thought they were a bit light / unstable for the O300.
Some nice sharp spikes going into the floor will help too.
Are these spikes required for a linoleum floor?

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Re: lost with monitor stands

Postby Hugh Robjohns » Mon Feb 18, 2013 12:06 pm

Bob Moose wrote:The most important thing is damping the low frequency vibrations properly.

A floor stand doesn't 'damp' vibrations -- that's not what it's is for, and not what is necessary.

The idea of the stand is to position the speaker rigidly in space in such a way that it can't move. As the drive units move back and forth in the speaker, the Newtonian laws of motion imply that the cabinet will want to move in the opposite direction, and the stand is there to stop that from happening, so that all the voice coil energy goes into moving the air, not the cabinet.

The vibration damping concept is only valid where the speaker has to be mounted on something that isn't very stable, or which is likely to vibrate and resonate -- like shelves and desktops.

I have no idea if it is better to have a very heavy stand that damps all vibrations before they go to the floor, or a stand that propagates all vibrations into the floor and then the floor acts as a damper.

You want a well engineered stand that doesn't move. End of story. That generally means soemthing with adjustable spikes or feet that can be levelled accurately, and a construction that doesn't resonate of ring -- usually achieved with internal damping like sand. Heavier stands are obviously less likely to move than lighter stands, but a well-designed lightweight stand is perfectly effective, too.

Height-adjustable stands are usually terrible because most mechanisms are rather feeble and wobbly.

I have several different stands here, with differnt heights and load bearing capabilities. I generally prefer sturdy welded steel frames with adjustable feet, and some have thin flat plates at the top, others have no plates and the speakers sit directly on the tops of the frames -- secured in both cases with 'blu-tak'.

However, I also have Zaor wooden stands which are height-adjustable and they are extremely good. I reviewed them here (and bought them!):

http://www.soundonsound.com/sos/jan12/a ... onitor.htm

I would have no hesitation using them for O300s... and in fact I anticipate using them when I review the O310s shortly...

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Re: lost with monitor stands

Postby Bob Moose » Tue Feb 19, 2013 12:06 pm

thanks for your answer Hugh

Hugh Robjohns wrote:
A floor stand doesn't 'damp' vibrations -- that's not what it's is for, and not what is necessary.

The idea of the stand is to position the speaker rigidly in space in such a way that it can't move. As the drive units move back and forth in the speaker, the Newtonian laws of motion imply that the cabinet will want to move in the opposite direction, and the stand is there to stop that from happening, so that all the voice coil energy goes into moving the air, not the cabinet.

The vibration damping concept is only valid where the speaker has to be mounted on something that isn't very stable, or which is likely to vibrate and resonate -- like shelves and desktops.
OK, I understand now. My floor is very heavy and stable (100% concrete, no air gaps) so I only need stands that do not move at all

You want a well engineered stand that doesn't move. End of story. That generally means soemthing with adjustable spikes or feet that can be levelled accurately, and a construction that doesn't resonate of ring -- usually achieved with internal damping like sand. Heavier stands are obviously less likely to move than lighter stands, but a well-designed lightweight stand is perfectly effective, too.

Height-adjustable stands are usually terrible because most mechanisms are rather feeble and wobbly.
The problem is I found very few fixed-height stands (Ultimate Support for example). Maybe one of them has exactly the required height, but I will have to check it.

Regarding adjustable stands, maybe the usual "topline" K&M stands are ok, no idea actually
http://produkte.k-m.de/en/Speakerlighting-and-monitor-stands-and-holders/Speaker-stands/21455-SPEAKER-STAND-black
http://produkte.k-m.de/en/product?info=584&x046d0=bs5756tkjj5ki94e05t4gl8na7

I have several different stands here, with differnt heights and load bearing capabilities. I generally prefer sturdy welded steel frames with adjustable feet, and some have thin flat plates at the top, others have no plates and the speakers sit directly on the tops of the frames -- secured in both cases with 'blu-tak'.
Are such stands available commercially, or is DIY / custom building required?
Also, from an acoustics point of view, is blu-tak better than the Neumann / K+H solution (screwing the speakers on a plate or a U-shaped bracket)?

However, I also have Zaor wooden stands which are height-adjustable and they are extremely good. I reviewed them here (and bought them!):

<a href="/sos/jan12/articles/zaor-standmonitor.htm" target="_blank">http://www.soundonsound.com/sos/jan12/articles/zaor-standmonitor.htm</a>

I would have no hesitation using them for O300s... and in fact I anticipate using them when I review the O310s shortly...
Not really inexpensive, but if I don't find any cheaper solution I guess I can save a bit and buy them later. That said I don't really need height adjustment: the speakers will remain at ear height (seated position).

Best regards
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Re: lost with monitor stands

Postby Hugh Robjohns » Tue Feb 19, 2013 12:28 pm

Bob Moose wrote:The problem is I found very few fixed-height stands (Ultimate Support for example). Maybe one of them has exactly the required height, but I will have to check it.


I'm not a big fan of ultimate support stands... I don't know what height you need the O300s to end up, but there are plenty of hifi speaker stand manufacturers around the world that make good, solid, fixed-height stands with a wide range of heights and weight capabilities.

I don't what's available in your part of the world, but I like the SL stands from Atacama, for example.

http://store.atacama-audio.co.uk/c/speaker-stands_sl

..
Regarding adjustable stands, maybe the usual "topline" K&M stands are ok


Not really. The tripod base is good... but a single vertical pole is going to flex and move. Acceptable compromise for a small PA speaker but far from ideal for a reference monitor.

Are such stands available commercially, or is DIY / custom building required?


They are certainly available commercially in the UK -- and I imagine through hifi dealers around the world. You could also commission a local metal fabricator to build something suitable for not a great deal of money... Or build something substantial from timber. PW described his own DIY design here:

http://www.soundonsound.com/sos/1995_ar ... tands.html

..
Also, from an acoustics point of view, is blu-tak better than the Neumann / K+H solution (screwing the speakers on a plate or a U-shaped bracket)?


It's not quite as secure, obviously, although it's always a struggle to remove speakers once they've been blu-taked in place for more than a few days! Few speakers have threaded bolt holes on their bases, so blu-tak is the only viable solution in most cases.

Not really inexpensive...


Yes, but I look on the stsand as a critical element in the whole monitor system -- along with the room acoustics and the monitor controller. Any weak links in this part of the chain degrades the monitoring accuracy, and if you're paying £3k on decent monitor speakers a few hundred on a well designed stand is a sensible investment in my bnook -- and should be something that will remain in use even when the speakers are upgraded.

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Re: lost with monitor stands

Postby Bob Moose » Mon Mar 25, 2013 8:41 pm

Well finally I bought the Atacama SL-1000 stands

There are 2 things I'm not sure about:

a) It is recommended to fill them with metal fillings (a.k.a. Atabites). I thought it would be best to fill them completely, but some people told me it is usually better to fill only 2/3 of them, otherwise there may be too much bass with some speakers. Of course it depends on the speakers, and (I guess) on the acoustic treatment, or lack of it. What should I do for O300 speakers?

b) How much blu-tak is required?
* only on the four speaker stand plate corners
* only along the four speaker stand plate edges
* should cover the total surface of the speaker stand plate

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Re: lost with monitor stands

Postby GIK Acoustics » Mon Mar 25, 2013 9:09 pm

Sand should work just fine, no need to go with metal beads IMO. And no, you should fill it all the way. The point is to fill the area so it doesn't resonate and so that it adds rigidity. Its much cheaper to build and ship hollow stands and let the customer fill them instead of building solid, heavy stands and shipping them, so most stands will have a hollow section to allow you to add it yourself.

One thing I do want to point out to anyone who stumbles on this thread is, while Hugh has had some excellent posts above, speaker stands do serve a secondary purpose. Decoupling is typically skipped when talking about speaker stands and is always something to keep in mind as well.
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Re: lost with monitor stands

Postby Hugh Robjohns » Mon Mar 25, 2013 9:34 pm

The stand filling is to add mass to the stand as well as to damp the resonance of the metal pipes and the trapped air. Lead shot, dry sand, and even (fresh) kitty-litter are all recommended fillings by different people. Again, some recommend filling two-thirds, there's all the way. It makes more sense to fill them completely as far as I can see (and hear).

Blu tak -- small blobs in each corner will be sufficient. It's really only to stop the speakers falling off if nudged. Pieces the size of large peas or small grapes is sufficient, and then press the down firmly to flatten out the blu tak.

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Re: lost with monitor stands

Postby Bob Moose » Tue Mar 26, 2013 11:57 am

Thanks Hugh and Alexander

I will fill them completely (it looks more logical to me as well) with lead shot because it's heavier than sand and the oven is sluggish there anyway
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Re: lost with monitor stands

Postby fay spook » Tue Mar 26, 2013 1:48 pm

How about trying the top plate spikes that came with the stands? (unless I am mis-viewing the online pictures) After all it is the manufacturer recommended set up.......

I am still not sure stands dont deal with vibrations. Play some music with stands undamped and put your hands on the stand legs. You will feel a vibration from the speaker, you dont have to play this very loud to feel this so it wont be the air in the room doing this. Filling the stand will make the stand more massy and so it will require more energy to make it vibrate the same amount. Please tell me what is happening to the energy here? Is it being damped? Reflected back into the speaker (the vibration taking the "easiest" path? etc
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Re: lost with monitor stands

Postby Bob Moose » Tue Mar 26, 2013 3:53 pm

fay spook wrote:How about trying the top plate spikes that came with the stands? (unless I am mis-viewing the online pictures) After all it is the manufacturer recommended set up.......

Yes either the spikes or other "shoes" they make (suited to various kinds of floors) are mandatory, at least because the floor is not 100% flat

I am still not sure stands dont deal with vibrations. Play some music with stands undamped and put your hands on the stand legs. You will feel a vibration from the speaker, you dont have to play this very loud to feel this so it wont be the air in the room doing this. Filling the stand will make the stand more massy and so it will require more energy to make it vibrate the same amount. Please tell me what is happening to the energy here? Is it being damped? Reflected back into the speaker (the vibration taking the "easiest" path? etc

I don't really know either. At the moment the stands are empty and reasonably stable (hard linoleum cuts compensate for the floor irregularies). You can feel some vibrations in the stand, and when playing low frequencies at high level you can feel them a bit in your feet too. But honestly it already sounds very good and I guess we are just talking about a light improvement
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Re: lost with monitor stands

Postby GIK Acoustics » Thu Mar 28, 2013 8:06 pm

fay spook wrote:I am still not sure stands dont deal with vibrations. Play some music with stands undamped and put your hands on the stand legs. You will feel a vibration from the speaker, you dont have to play this very loud to feel this so it wont be the air in the room doing this. Filling the stand will make the stand more massy and so it will require more energy to make it vibrate the same amount. Please tell me what is happening to the energy here? Is it being damped? Reflected back into the speaker (the vibration taking the "easiest" path? etc

Yes but really - unless the actual stand is resonating - adding mass to the stand doesn't affect the response.

What is happening is that the speaker stand itself isn't vibrating as much, but the same amount of vibrations will pass through it. So, adding that mass makes the speaker stand vibrate less, but the transmitted amount of sound is still the same, as it uses more energy exciting the extra mass, so its in equivalence still. Obviously this makes sense as changing the speaker stand won't change the energy the speaker is putting out.

This is also where decoupling comes in - decoupling on the other hand reduces transmission. But adding mass to the stand does not.
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Re: lost with monitor stands

Postby Exalted Wombat » Thu Mar 28, 2013 8:17 pm

You're in danger of paying silly money for something that needs to do a simple job, hold your speakers in the right position and not move around or rattle!

Buying something solid and heavy can be expensive. Boxes, bricks and sand aren't. Maybe the speakers could sit on something that was also useful for storage?
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Re: lost with monitor stands

Postby Bob Moose » Fri Mar 29, 2013 3:54 pm

Exalted Wombat wrote:You're in danger of paying silly money for something that needs to do a simple job, hold your speakers in the right position and not move around or rattle!

Buying something solid and heavy can be expensive. Boxes, bricks and sand aren't.

More or less what I am doing actually. Luckily I got the SL1k stands for a very good price, and lead shot is not something expensive either. But the cinder block + sand (or concrete) solution should work very well indeed (provided you have a solution if the floor is not exactly flat -- even 1 mm of difference can be a problem).

Maybe the speakers could sit on something that was also useful for storage?

This could not work in my room because it is too small. It would be difficult, or even impossible to reach the storage place. Anyway there would not be much space for storage.

Also, I'm afraid putting the speakers on a cupboard or something like this could turn it into a kind of bass resonator when it's empty. Perhaps with very thick and heavy damping material between the speaker and the cupboard? In any case you would need a very solid piece of furniture, with independent height-tunable feet, and military-grade door assembly to be sure they do not vibrate at all when playing bass parts.
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Re: lost with monitor stands

Postby fay spook » Fri Mar 29, 2013 4:15 pm

Exalted Wombat wrote:You're in danger of paying silly money for something that needs to do a simple job, hold your speakers in the right position and not move around or rattle!

Buying something solid and heavy can be expensive. Boxes, bricks and sand aren't. Maybe the speakers could sit on something that was also useful for storage?

If you put a speaker on a solid, as in bricks or storage, stand you will have the bass driver is driving the room in a slightly different way. Not a full 2pi or soffit but a percentage towards that.

I was hoping someone might have moved the view on a little here. When your speaker is making a noise the cones and the cabinet will be vibrating. I want that energy out of the speaker as quickly as possible to stop any smearing. With the stand transmitting this energy away from the speaker you get the speaker doing only what it should do. Too massy and the energy will be reflected back into the speaker. I have pointed out earlier in this thread that we are only talking about small levels of energy here but isnt every step to improving sound worth while?

If you dont believe me try this experiment. Punch a wall. Simple. It will hurt because of the equal and opposite force from the wall/the energy you hit the wall with not going anywhere. Now punch a wall with a balloon in between, thats better. That will be your soft decoupling, the trouble here is the speaker isnt being held rigidly. Finally punch some aluminium, now that hurts a lot less than hitting a wall and it makes some noise. To me it looks like the energy has been transmitted into the metal more effectively. hence light but rigid stands sounding best. Also with the type of construction that leads to a light rigid stand you will get a stand that has a high resonant frequency. At higher frequencies speakers have less energy shaking around so the stands are less likely to excited into resonance.

Of course I understand a stand has to keep a speaker still, I come from the hi-fi end of things where we were spiking speakers when you "pros" were rolling speakers on casters- I mean you BBC.
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Re: lost with monitor stands

Postby Hugh Robjohns » Fri Mar 29, 2013 6:03 pm

fay spook wrote:I come from the hi-fi end of things where we were spiking speakers when you "pros" were rolling speakers on casters- I mean you BBC.

;)

Foldback speakers in radio and TV studios were usually on wheeled stands for very obvious and practical reasons, but I can't think of any control rooms I worked in over the last 30 years where the main monitoring speakers were on castors! Admittedly, I can't think of any on spikes, either, but all the bigger ones were on stands with fixed feet as far as I can recall, and the smaller ones on fixed shelves.

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Re: lost with monitor stands

Postby Bob Moose » Fri Mar 29, 2013 6:07 pm

fay spook wrote:
When your speaker is making a noise the cones and the cabinet will be vibrating. I want that energy out of the speaker as quickly as possible to stop any smearing. With the stand transmitting this energy away from the speaker you get the speaker doing only what it should do. Too massy and the energy will be reflected back into the speaker.


When the floor is hard enough, there is something I don't get about decoupling the speaker from the stand or the stand from the floor. The speaker can move a bit because the decoupling material is not rigid, so the sound is smeared as well.

About the mass reflecting energy back to the speaker: would a very light but extremely rigid and stable stand (think of spaceship materials) reflect less energy than an equally rigid and stable, though very heavy stand?
Sorry I forgot a bit the physics I learnt at school.
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