If (you don't like foam)
- increases the number of aluminum waveguides,
- increases the cost of the material,
- increases assembly time,
- reduce the impedance peaks as in the 54m42 project.
- use alveolar polypropylene 54m42 project.
- add a few pieces of foam,
- reduce the impedance peaks in five minutes,
- the budget remains below 100 euros of material.
The use of foam rubber cubes is only one option, it can be used by those who want to try to make prototypes, saving on the purchase of materials and reducing construction times.
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Then it is time to abandon most speakers… they almost all use some kind of damping. Foam is not particularily effective, as pictured it would be more like a slight push towards aperiodic… i use this same technique if the bass in one of my miniOnkens needs damping down.
dave
They can be open at one end (1/4 wave line) or closed (1/2 wave) or both (1/2 wave). Most are quarter-wave but there is a quite large design space.
This design is a bunch of undamped TLs with lots of ripples, lots of pipes spreads those out, we see the same concepts in DMLs and in speakers like the Hegeman wher ethe pipes are inside the box.
How old were they? What were they? How well designed? There was a HUGE change in TLs after 2000 as proper modelers started to appear. Instead of a guess at the right size, you could see what the pipe did by modeling it.
I am certainly well satisfied with the TLs i am listening to, the ones downstairs, and some in the field (one set i loaned out and he declined to return them :^) — used as bass support for an OB Lowther.
dave
can't say on all three counts as they didn't make any impression on me to want to inquire about them.
The exact material and its location are of little consequence as long as the benefits outweigh the detriments. Engineering is a series of compromises. To each his own, but having absolutist views on minor things tends to make progress more difficult.
"Newer" Quad ESLs use internal damping in the form of a thin mesh, an external metal mesh, an external Mylar dust cover, and grille cloth. Then of course there's the structure that makes up the driver itself: circuit board that's only about 36% open area and the grid that holds it. That's a lot of stuff in the path, and reviews tend to be quite favorable (other than dynamic limits).
Acoustat used heavy felt pads on the back of many of their electrostatics.
Bohlender Graebener uses internal damping in their planar magnetics.
Several classic speakers used foam grilles.
Everything in moderation.
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Since I was one of the people that suggested the addition of damping to tame the resonances, you were essentially calling my idea a bad one. I provided some examples to refute that, included a "to each his own" disclaimer, took no absolutist positions, and tried to carefully explain my view. That's backlash?
Are we here to discuss ideas, present data, and help people with their projects, or is this just about broadcasting opinions? If it's the latter, it's of little interest to me.
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On "move on" move on
On "move on" move on. I have use the last posts to increase my low level english. I have read backslash (\) indeed was "backlash" (I am a IT teacher).
The first think in my mind reading "move on" was: where? The first phrase on my home page is: "The only loudspeaker enclosure invented in the 21st century". There are two event to confuting it.
1) MDD is not a innovative tecnology.
2) MDD tecnology is not the only.
Thanks if You want report they.
I'm over 60 and cannot move to market the MDD tecnology. It isn't a money problem, is a time problem. A full time work is requied for factory managing, with developping stop. I prefer developping to production, the posts of DiyAudio forum help me to developping.
Texts as " ... a slight push towards aperiodic…" (planet10) are the origin of new points of view for damping on MDD tecnology (under processing).
On "move on" move on. I have use the last posts to increase my low level english. I have read backslash (\) indeed was "backlash" (I am a IT teacher).
The first think in my mind reading "move on" was: where? The first phrase on my home page is: "The only loudspeaker enclosure invented in the 21st century". There are two event to confuting it.
1) MDD is not a innovative tecnology.
2) MDD tecnology is not the only.
Thanks if You want report they.
I'm over 60 and cannot move to market the MDD tecnology. It isn't a money problem, is a time problem. A full time work is requied for factory managing, with developping stop. I prefer developping to production, the posts of DiyAudio forum help me to developping.
Texts as " ... a slight push towards aperiodic…" (planet10) are the origin of new points of view for damping on MDD tecnology (under processing).
I have prepared a couple of drawings to clarify how the wavefronts emitted by diffraction with MDD are propagated. They are visible on the acoustic page, on the same page some considerations on the optimization of the response to low and high frequencies.
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21M7 a new MDD project
The sound quality of the 21M7 project is excellent, the construction is simple and economical. With about 50 euros you can quickly build a pair of omnidirectional stereo speakers superior to any other type of cabinet with the same budget.
The sound quality of the 21M7 project is excellent, the construction is simple and economical. With about 50 euros you can quickly build a pair of omnidirectional stereo speakers superior to any other type of cabinet with the same budget.
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