PlastiPerf™ Panel for ELS Stators

[fperra]

I'm in the process of gathering material for an ELS project and came across this perforated plastic material:
Perforated material punched with round holes
It looks like it has a lot of potential for Stator panels. One side could be made conductive by spraying with automotive copper spray. Any opinions fron the experts on this forum?

[alexberg]

Originally Posted by fperra

I'm in the process of gathering material for an ELS project and came across this perforated plastic material:
Perforated material punched with round holes
It looks like it has a lot of potential for Stator panels. One side could be made conductive by spraying with automotive copper spray. Any opinions fron the experts on this forum?

It's even more challenging to coat PP in respect to PET (membrane)...
Second question would be dimensional stability

[geraldfryjr]

I have used a similar technique on my micro drivers using aluminium foil tape as the stator on some prepunched pc breadboard material and clear acrylic enamel as the stator coating.

I have considered this method in the past but I didn't have any luck finding a suitable perforated plastic material that was strong enough for a larger type panel that had a large area of openness.

A similar method was also described by one of the Peter's (it was either Baxandall or walker) when they first made their headphone units.

Alexburg is very correct about his points as I have researched this quite extensively but it was back in 2004 and a lot has changed since then as far as availability of different materials.

jer

P.S. Styrene would be a better choice if you could find it prepunched with some 5/32" holes.

[alexberg]

Assuming low or no daylight exposure and relatively low, room temperature, it seems reasonable to give it a try.
Polyolefins are prone to cold flow, so I would not use it as a part of load bearing panel structure.
You can't use then masterpieces developed by fellow DYIers with perf metal as a reference.
In respect to the PP painting/coating (real life experience )
Plastic Bumper Repair - Plastic Bumper Repair - How-To Center
3M Automix Polyolefin Adhesion Promoter 05907
Styrene is easily destroyed by most paints/thinners/solvents and quite brittle.
What about ABC/PVC plastic? Like McMaster-Carr

[bear]

The question really is, why?

What benefit does this afford?

How does it compare with ur basic powdercoated metal stator?
Wire stator?

_-_-bear

[moray james]

Styrene light louvre material is really junk plastic which is loaded with high amounts of plastizer so the grids will not break when they are ejected from the molds. They use regrind and the actual plastic consistancy will vary greatly form piece to piece. That said it is strong (enough) and easy to work with takes paint and glue (there are adhesive issues) though solvent welding is the best method to insure long time joint strength. Acoustat used styrene light louvre to good effect and with proper care and handling will last a good long time.
You also have to take into account the plastic is in close proximity to highly charged air and there is a very small quantity of ozone produce by the speaker which you should know eats everything. Acoustats can be run all day every day for about fifteen years before any significant degridation starts to appear. There are very many Acoustats out there which are 30 years old and still functioning, not as well as new mind you but running all the same. I think that for diy applications the styrene grid louver offers an inexpensive easy to work with base upon which to build esl panels be they perforated metal or tensioned wire as the grid structure adds both strengtrh and damping. While available in half inch (as used by Acoustat) and three eights thickness I prefer the three eights thick material as it minimises the tunnel length presented to the air flow off the diaphragm.
Light louvres are available made from acrylic which is in every way superior to styrene but in most cases is not normally stocked by suppliers due to cost. I think a general expected life span of fifteen very good years and an additional possible fifteen is more than reasonable for diy builds. I dont think I have gone more that three to five years without wanting to change a design anyway. Wire stators offer the highest quality and highest consistency of dielectric of any method of build I can think of.
All methods of construction come with their own issues and special requirements. It will depend upon the builders skills knowledge and tools at hand to determine which method best suits them or a given project. HI tech solutions to design problems almost always come with hi tech problems you must solve. Take for example the Quad 63 which was at the time an ultra hi tech esl design. They have a hord of construction problems and quality issues and even after a multi year re design are in my estimation still problematic. Comepare the Quad to the ultra simple Acoustat andy you have your proof in decades of trouble free service. Now I am not saying ther are not old Quads out there still playing music because there are, what I am saying is that no other commercial panel has near the track record of the Acoustat. So as I see it if you want a superb esl which will last a life time look to build a better Acoustat.
The other single biggest issue that I see with esl speakers is that manufacturers and diyèrs alike persist in designing full range panels. I believe the compromises required to achieve substantial bass output come at the expense of efficiency and dispersion and as such dimish the qualities most sought after in esl speakers. Dynamic driver make excellent bass inexpensivly and are simple to drive. Calvin can attest to what can be achieved with a good hybrid approach. ESL`s can make bass that is not the point here the point is they are by no means the best option for making bass. The direct radiator cone woofer is the king of that castle in most every way.
Use the technology at hand that meets your requirements best and that gets the job done. Simplicity is perhaps the most difficult thing to achieve and the devil as always lies in the details. Best regards Moray James.

[fperra]

Originally Posted by bear

The question really is, why?

What benefit does this afford?

How does it compare with ur basic powdercoated metal stator?
Wire stator?

_-_-bear

You're probably right. I think I'll stick with the perforated metal stators.

[teslaboy]

hi
i believe that every type of panel has a specific voice.
i collect esl speakers and have accumulated data on many panel types.
while i agree with morey james on the robustness of the acoustat.
i believe the acoustat panel lacks transparency
I have owned many acoustat speakers along with their direct drive amps .
i did a test with the acoustat DD amp using both the 8 and 9 inch panels
along with 8 inch panels modified by roger west using the copper ring and 2 micron
diaphrams, they all sounded great and the 2 micron panels being more transparent
as well as more highs, so i thought what if i ran a martin logan cls 2Z panel.
i was astonished at the magnitude of improvement by the ml panel.
so i decided to test some of my panels from many manufacturers.
i built a jig with a esl transformer and bias supply and limited the response to
350 hz. the result was the most transparent panel was the innersound eros 3.5
a fiberglass panel with vertical slits.followed by the new type of ml panel
and a bunch in between .the second from the last was the 2 micron acoustat
panel which was tied with the final .3 panel and dead last was the stock acoustat
panel .

so there is no one best type each has its own voice so experiment.
also a few esl speakers used plastic stators eg quad 57,dayton wright

[bentoronto]

What can be added to the exemplary post by Moray James and teslaboys's comments? +1.

Seems to me, of all the challenges facing a builder, just finding a nice louver-like plastic structure jet-propels you past the worst challenges.

Dayton-Wright panels are fancy louvers, no doubt custom cast. Mike spray-painted conductive paint on the working edges and fastened pairs together (after putting some coated SaranWrap in the middle, of course).

These panels are roughly 8 x 16 inches and you just bolt together a bunch. He did it on the surface of a virtual sphere... no doubt patented the idea too.

There are, of course, other system issues that make it work for the Dayton-Wrights that may be different for you (like not having any spare sulfur-hexwhatsis gas around).

Ben

[bentoronto]

Just another 2-cents to add.

I think there is some excessive exuberance about rigidity in woofer cabinets (for non-sealed boxes). But a lack of care for rigidity on largish ESL panels...maybe because we don't spend much time with our palms on them feeling for vibration.

This may account for some sound anomalies with some ESLs.

With plastic panels, you can have some depth leading to strong girder strength that is not as easy to achieve with welding rods, large thin sheets of metal, and other common methods.

Ben