Granite - is it the ultimate cheap upgrade or is it just MY speakers?
Speakers Wilson Benesch Square 2.
working on the logic that my tweeters MUST be suffering from the vibrations i could feel on the front of the cabinet next to them - and knowing the massive improvement out boarding the crossovers had made - I decided to do the same with the tweeters.
Long story short - I bought a piece of granite cut to size to fit the top of each speaker and 120mm tall. Due to the weight - a lot - nearly solid high "tack" feet were used and the tweeters mounted in the cut out on the granite.
The transformation was spectacular.
What was more interesting was the improvement was almost identical with the tweeters IN the cabinets as before.
I guess its fairly self explanatory - the woofer is trying to move the cabinet back and forth in the opposite direction to the air. The entire floor standing cabinet is trying then to pivot about the floor spikes and there fixing into the speaker - the tiniest of available flex down there and your allowing 50x that at the top where the tweeter is. If you add a compact 25kg mass at the top of the speaker cabinet you vastly alter the entire dynamic. Your woofer now has to shove an extra 25kg of air to move the cabinet the same distance as before.
What I thought was vibration from inside the cabinet turned out to be front back motion - the vibration on front of my speaker cabinet is now almost un noticeable to the touch.
As a chunk of Granite this size is about $5 please give it a go - id live to know it its just a trick unique to my speakers or universal.
It has to be the cheapest upgrade since getting rid of bell wire.
Speakers Wilson Benesch Square 2.
working on the logic that my tweeters MUST be suffering from the vibrations i could feel on the front of the cabinet next to them - and knowing the massive improvement out boarding the crossovers had made - I decided to do the same with the tweeters.
Long story short - I bought a piece of granite cut to size to fit the top of each speaker and 120mm tall. Due to the weight - a lot - nearly solid high "tack" feet were used and the tweeters mounted in the cut out on the granite.
The transformation was spectacular.
What was more interesting was the improvement was almost identical with the tweeters IN the cabinets as before.
I guess its fairly self explanatory - the woofer is trying to move the cabinet back and forth in the opposite direction to the air. The entire floor standing cabinet is trying then to pivot about the floor spikes and there fixing into the speaker - the tiniest of available flex down there and your allowing 50x that at the top where the tweeter is. If you add a compact 25kg mass at the top of the speaker cabinet you vastly alter the entire dynamic. Your woofer now has to shove an extra 25kg of air to move the cabinet the same distance as before.
What I thought was vibration from inside the cabinet turned out to be front back motion - the vibration on front of my speaker cabinet is now almost un noticeable to the touch.
As a chunk of Granite this size is about $5 please give it a go - id live to know it its just a trick unique to my speakers or universal.
It has to be the cheapest upgrade since getting rid of bell wire.
+1. It's not a very sexy idea, but the physics work. My advice has been, and remains:
1 - Minimize the total surface area with the floor.
2 - Minimize the movement of the speaker cabinet due to the opposing forces placed on it from the drivers. This means mass or clamps
3 - Minimize cabinet flexion.
No one likes doing 2 for some reason. 🙂
Best,
Erik
1 - Minimize the total surface area with the floor.
2 - Minimize the movement of the speaker cabinet due to the opposing forces placed on it from the drivers. This means mass or clamps
3 - Minimize cabinet flexion.
No one likes doing 2 for some reason. 🙂
Best,
Erik
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I was thinking of tweaks that didn't involve a speaker redesign. 🙂
A midrange or tweeter could in theory do the same, but you are right, I'd guess 80-90% of the force is in the bass, so this technique should cancel most of it. But still, a strong midrange at volume in a light weight cabinet could do the same. Lightweight in this case is heavier than most people think.
Best,
Erik
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80-90% is probably an underestimate. The rocking force is a function of the moving mass and the distance it is moving.
But for a FR (what i mostly use) or mid or tweeter one has to worry about motions burying the low level information. We often brace a FR to as many box panels as possible so that the baffle does not get all the load itself. It works well. One of my gurus puts his tweeter pods on a suspension to keep them from being affected by the bass enclosure.
My push-push subs (2xSDX10 sealed) have boxes (15mm ply) that you can pick up with a finger, but load the drivers and it is a significant lift. Too much box mass can be counterproductive if it moves the potential box-resonances low enuff to get excited -- we have had that problem more than once where the thinwall box has no significant resonance issues but after laying on thick solid wood veneer (¼-½") the box resonance became a significant issue.
dave
But for a FR (what i mostly use) or mid or tweeter one has to worry about motions burying the low level information. We often brace a FR to as many box panels as possible so that the baffle does not get all the load itself. It works well. One of my gurus puts his tweeter pods on a suspension to keep them from being affected by the bass enclosure.
My push-push subs (2xSDX10 sealed) have boxes (15mm ply) that you can pick up with a finger, but load the drivers and it is a significant lift. Too much box mass can be counterproductive if it moves the potential box-resonances low enuff to get excited -- we have had that problem more than once where the thinwall box has no significant resonance issues but after laying on thick solid wood veneer (¼-½") the box resonance became a significant issue.
dave
This is the Mk2 version mid production. The first was just a cube of grey granite that looked horrible, these (if you see the top) are a a much better an more fitting color for the speakers. Annoyingly only available in 25mm sheets. I am fitting super tweeters (Recommendations welcome) so they are awaiting the cutout and cable channel cutting before they are glued together, trimmed flush and polished - you can see they are 5mm oversized to allow trimming.
Just as a point of interest - the big difference was in the upper mid range - where im guessing the amplitude of the lateral movement may be a substantial part of the wavelength. The other area was the control of the bass at lower levels. The treble benefited from better positioning and separation but that was a small improvement.
Just as a point of interest - the big difference was in the upper mid range - where im guessing the amplitude of the lateral movement may be a substantial part of the wavelength. The other area was the control of the bass at lower levels. The treble benefited from better positioning and separation but that was a small improvement.
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Dave,
For sure, most of it has to be in the woofer, as it has the largest motor and largest demands. I love the tweeter suspension idea. I got lost however when you said:
Best,
Erik
For sure, most of it has to be in the woofer, as it has the largest motor and largest demands. I love the tweeter suspension idea. I got lost however when you said:
Did you mean box as in cardboard?
Best,
Erik
Carboard?
Here is a visualization of one of our boxes. You can see the brace with all the circular holes that brace the back of the driver to the back, top & bottom of the box.
dave
Here is a visualization of one of our boxes. You can see the brace with all the circular holes that brace the back of the driver to the back, top & bottom of the box.
dave
An interesting point - some of the Russian speakers I have come across the entire front panel is cast as part of the woofer basket in one. (obviously a good idea especially if production cost is not a factor) But then the bolts that hold it in place travel all the way through to the back and are screwed tight with very long hex nuts like you use on threaded stud to connect two together.
This looks untidy until you find out they are to attach bracing rods that screw in and then touch the back wall. This is clearly to reduce lateral movement of the cabinet.
[I have only seen it] It is employed on portable theater speakers where the rest of the construction is very light for portability.
This looks untidy until you find out they are to attach bracing rods that screw in and then touch the back wall. This is clearly to reduce lateral movement of the cabinet.
[I have only seen it] It is employed on portable theater speakers where the rest of the construction is very light for portability.
As there seems to be a good level of agreement that this will probably have a good result for all speakers does anyone wish to order from my new line of Custom Cut, Fully Polished, Granite, Critical Mass Lateral Movement Speaker Dampers.
They are 8 9's purity 99.999999 natural Granite, none magnetic, totally none conductive, have absolutely no electrical characteristics worth measuring. They are the result of decades of research and development and each one is individually blessed by the local Orthodox Catholic Priest in between blessing the engines of S Class Mercedes (they really do that here).
They start at an exceptionally reasonable $495 per pair plus shipping.
[edit] You do have to sign a disclaimer as a tiny slip whilst trying to stack one on top of the other can result in your finger tips exploding. Which hurts. A lot.
They are 8 9's purity 99.999999 natural Granite, none magnetic, totally none conductive, have absolutely no electrical characteristics worth measuring. They are the result of decades of research and development and each one is individually blessed by the local Orthodox Catholic Priest in between blessing the engines of S Class Mercedes (they really do that here).
They start at an exceptionally reasonable $495 per pair plus shipping.
[edit] You do have to sign a disclaimer as a tiny slip whilst trying to stack one on top of the other can result in your finger tips exploding. Which hurts. A lot.
Why is it that sound pros argue just the opposite and say studio monitors should float on foam isolator a for the max bass and sound impact?
Auralex ProPAD | Sweetwater.com
Reviews:
http://www.sweetwater.com/store/detail/ProPAD/reviews
Auralex ProPAD | Sweetwater.com
Reviews:
http://www.sweetwater.com/store/detail/ProPAD/reviews
xrk, I think decoupling is advised because it's half-right. The issue is usually that no one does the right combination, IMNSHO. That is, 1 - minimize surface contact area and 2, add mass. Usually they achieve 1, or some version of it which could be achieved by decoupling the speaker from the floor. The idea there is to prevent vibrations from traveling through the floor, faster than they do via the air, not to mention exciting floor modes much like the body of a musical instrument.
What would be cool is to measure some of this. If any of this is right for instance, a 2 tone signal, say at 50-100Hz and another around 4 kHz should show the problem. 🙂 Either the woofer shows changes, or the tweeter shows phase shifts modulated by the woofer which then are reduced after adding mass.
Of course, this is the internet where some half-wit like me can pretend to be an expert on anything. This is just a guess until measurements arrive to further guide us. 🙂
Best,
Erik
What would be cool is to measure some of this. If any of this is right for instance, a 2 tone signal, say at 50-100Hz and another around 4 kHz should show the problem. 🙂 Either the woofer shows changes, or the tweeter shows phase shifts modulated by the woofer which then are reduced after adding mass.
Of course, this is the internet where some half-wit like me can pretend to be an expert on anything. This is just a guess until measurements arrive to further guide us. 🙂
Best,
Erik
A speaker is a complex item… something may improve it in one direction and degrade it in another.
dave
dave
So from what I've read in previous threads there is a line of thought which says that mass is more important than bracing in cabinet design. Does adding mass after the fact on top of the speaker like this have the same effect as building mass into the cabinet itself (through thicker, denser materials and such)? If so then this could truly help simplify cabinet construction significantly, could it not? (Just add mass during the setup phase instead of the construction phase?)
That would depend on what the cabinet walls are made off. I bet adding weight (not in the walls specifically) would help.
In a way it's very similar to the unsprung weight on a (for race or comfort) car:
Unsprung Weight
In that car you want the wheels to follow the road. But you don't want the bumps to influence the car body, kind of like our moving cones. The cones should move along to the signal that drives it. But the enclosure shouldn't add anything to that sound. That takes work to avoid enclosure resonances but also weight to counter the moving mass. Light cones and heavy enclosures help here. Behaving more like the race car.
So it's a balance of damping (like the shocks on the race or comfort car) and weight (keeping unsprung weight low).
To me its is high stiffness with high damping that is what is required. Higher mass means higher Q resonances which are harder to damp. A very stiff, but light, cabinet with very highly damped construction is what I seek.
This is also exactly what a race car does - more mass is not the way to go.
I am also suspect of the claims of high audibility of adding massive stones to the cabinet. Sounds like amplifier bricks to me.
This is also exactly what a race car does - more mass is not the way to go.
I am also suspect of the claims of high audibility of adding massive stones to the cabinet. Sounds like amplifier bricks to me.
Except, on a race car they bring down the weight of the wheels and brakes (the moving mass) to compensate for the car being light. Which is what I suggested. On our speakers that part would be the cones etc...
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