That's correct. It definitely isn't new, research into this began nearly two centuries ago. FEA is a new term to me, I had to look it up - Finite Element Analysis? I'm not an engineer.
We can use negative feedback in amplification and I thought why not for a tranducer. Single Degree of Freedom was the expression that I had heard a siesmologist freind use when discussing damage after the 2011 earthquake in Japan. With Mark Audio using light basket frames from dense polymer I wanted a method to add mass and hence my method evolved. It costs pennies.
I'm not making any calculation - for now I'll secure a strip of lead to the wood brace for mass. The only detractor is nut's head is visable on the front of the baffle which some may find odd or ugly! The nut on the front allows tightening to draw the weighted brace in towards the rear of the baffle. Still experimenting, however.
Regards
Last edited:
"Sound dampening of lightweight flooring" - Was hanging out at a place that sold Marble countertops, to purchase a few scrap pieces. They also sold flooring. One sample piece was a very nicely damped square, I noticed, in handling it. This was apparently by design. It was a showroom floor sample, so I knew they wouldnt sell it to me. But it's one place to look for such material, as this is a problem for them (as well) and clearly people have tried to solve it and productized their solution.
Imagine simply buying an already damped construction material instead of having to DIY? There may be a way to arrange it to have a nice cabinet finish as well. I bet it'd work damn good for the "foam-core" builds, as an alternative in going from foam-core to wood.
Imagine simply buying an already damped construction material instead of having to DIY? There may be a way to arrange it to have a nice cabinet finish as well. I bet it'd work damn good for the "foam-core" builds, as an alternative in going from foam-core to wood.
An abundance of great info and opinions folks.
Long before thinking of creating this thread, I had days of overthinking episodes of different strategies.
One was crafting the speaker bracing skeleton first, then gluing the inner outside wall to the skeleton. Thin ply or even polycarbonate sheet. Then I'd glue rectangular spacers to maintain distance to the outside thin wall made from the same quoted materials. These spacers would act as pseudo compartments to prevent sand from gravity compressing too.
The second idea was building the same concept with heat resisting materials, such as copper sheet and phenolic spacers. To allow me to cast molten bitumen, mixed with rock and sand.
A third idea would bring the concept to a waterproof level with polycarbonate, acrylic and silicone sealant to fill the compartment with a "kinetic" mixture of oil and fine particles.
Other ideas targeted the speaker basket and magnet systems themselves, such as adding mass to the magnet system or even gluing jars to the magnet, filled with sand.
I understand that mixing materials with different propagation velocities can be of benefit. Sand and steel balls can be of such example, however one needs to ensure a constant homogeneity of the particle mixture.
Long before thinking of creating this thread, I had days of overthinking episodes of different strategies.
One was crafting the speaker bracing skeleton first, then gluing the inner outside wall to the skeleton. Thin ply or even polycarbonate sheet. Then I'd glue rectangular spacers to maintain distance to the outside thin wall made from the same quoted materials. These spacers would act as pseudo compartments to prevent sand from gravity compressing too.
The second idea was building the same concept with heat resisting materials, such as copper sheet and phenolic spacers. To allow me to cast molten bitumen, mixed with rock and sand.
A third idea would bring the concept to a waterproof level with polycarbonate, acrylic and silicone sealant to fill the compartment with a "kinetic" mixture of oil and fine particles.
Other ideas targeted the speaker basket and magnet systems themselves, such as adding mass to the magnet system or even gluing jars to the magnet, filled with sand.
I understand that mixing materials with different propagation velocities can be of benefit. Sand and steel balls can be of such example, however one needs to ensure a constant homogeneity of the particle mixture.
One idea I had and even acted upon perhaps, was to decouple the speaker from the baffle entirely using a pliable material, in my case sheet rubber. Then re-couple the speaker basket / magnet to a suspended / floating mass behind it. All the driver has to "push against" in opposing reaction is the suspended mass arrangement. The baffle / cabinet is decoupled from vibrations caused by the driver being mounted to it. I did this on an open baffle, to keep the baffle from getting excited; then I went to the cork laminate,
In a closed cab, the acoustic energy radiated from the rear of the speaker can still excite cabinet panels.
Kind of the opposite of trying to get the baffle to resonate along with the cone.
try this
If you want a type of "black hole damping" try the following.
Get carpet for floors with rubber. If you put 3 to 5 of them as layers on all sides in the box. Its pretty dead.
Get carpet for floors with rubber. If you put 3 to 5 of them as layers on all sides in the box. Its pretty dead.
A few years ago, I made a "box in a box" speakers; the bass driver and cone tweeter both had individual enclosures inside a larger enclosure, and both mechanically isolated be soft foam gaskets between them and the front baffle - they are held in position by compression springs. I've also bolted 4.5kg lumps of cast iron to the back of speaker magnets.
Having done all that, I've come to the conclusion that an even dispersion throughout the frequency range, and a reasonably flat frequency response is more important, but an inert cabinet is important.
Ive used dry sand with good affect.its cheap and plentifull.gr8t thing about building diy speakers we are not constrained by pc hype to sell speakers using the latest board made by aliens on alpha centuri.
It would be nice if the sand could fit in the bottom of the woofer enclosure, but how to prevent dust and iron from migrating to destroy the motor and voice coil??
Frame it all the way around, then staple a piece of cloth cover over the sand. Unless you expect to ship it like that, without paying for the "No-Tip" service and assurance indicators.
It's for my new woofers, they are the scanspeak so I cannot destroy them.
I will stick with the idea of a double bottom , use a very thin piece of wood to separate the sand filled area.
I will stick with the idea of a double bottom , use a very thin piece of wood to separate the sand filled area.
Yeah, as usual the pioneers got it right the first time by building a rigid, massive framework to contain the driver and slipped the box over it using a bicycle tire inner tube to seal it.