Gladly!
https://www.amazon.se/dp/B0BFQCQWND
https://www.amazon.se/dp/B0BFQ5WM7S
I bought one of each, no idea if they are good or not. Expected delivery date is January 2nd, so I will be able to test them the weekend after.
I think the will be to stiff for absorbing the corrugations... But if not, the EPDM sealing on ClasOlsson could be a good choice. EPDM is a really good material...
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Yes, I think that for both OllBoll and me the two plates' "surround" needs to be aligned.
That rules out the E profile. The P profile could work though pending its dimensions.
Or do you have something else in mind?
That rules out the E profile. The P profile could work though pending its dimensions.
Or do you have something else in mind?
the amazon version does not mention shore, as far as i can see. and i have plenty of foam here (stiff foam, had even worse uneven compression) ... it is waaaay to stiff 🙁 anyone ever tried single ended foam ? (on only one part of the frame) i did my latest big tweeters like that. so far no problems and no differences in SPL. i used one of those rubbery doublesided tapes (0.9 mm). might not be of interest for push pull though. its permanent... so thats a down side for sure 🙂 unless you know how far you want to stretch the corrugated foil (witch you can do with a weight). for single ended its a benefit that you can just put it against the backside of a baffle without having to machine that baffle on the backside. only the front for a roundover or whatever form you like.
another idea i had but did not try, to use 2 different shore (hardness) types. also not usefull for push pull... so one double sided sticky one (or not sticky). and a normal really floppy one on the front side. this way it wont come off and has damping and wont end up into one of the magnets since one of the foam is just a little to stiff to do so.
this might work for single ended, not to sure about your push pull ones. since my 2 floppy foams chose randomly witch sides compressed first 🙁
another idea i had but did not try, to use 2 different shore (hardness) types. also not usefull for push pull... so one double sided sticky one (or not sticky). and a normal really floppy one on the front side. this way it wont come off and has damping and wont end up into one of the magnets since one of the foam is just a little to stiff to do so.
this might work for single ended, not to sure about your push pull ones. since my 2 floppy foams chose randomly witch sides compressed first 🙁
Ok, perhaps it is time to revisit old and discarded solutions once again; maybe the corrugation will withstand the pressure.
I got a crazy idea.
If one goes with a rear plane of solid alu, so no exposed kapton / mylar. Do we need the kapton / mylar? We'd only need something barrier to prevent the traces from shorting to the rear alu fill.
Now the best barrier might just be mylar or kapton, but in that case what if we only had the barrier around the traces? 12 um kapton with the pre applied adhesive is roughly as heavy as 14 um alu, so I could bump the filled plane alu to 20 um while still being lighter. And it should hold corrugations even better right?
The easiest to test with would be kapton with release liner but that is even more expensive than regular kapton.
I wonder if it would be possible to lay mylar / kapton on the ReMount glue and then cut it as if it was alu foil. Then spray the 3M 77, weed but then glue on top of say 20 um alu. Then cut say self adhesive 30 um alu and glue it on top of the mylar / kapton.
Or what if the 30 um acrylic adhesive is thick enough to act as electrical insulation by itself?
If one goes with a rear plane of solid alu, so no exposed kapton / mylar. Do we need the kapton / mylar? We'd only need something barrier to prevent the traces from shorting to the rear alu fill.
Now the best barrier might just be mylar or kapton, but in that case what if we only had the barrier around the traces? 12 um kapton with the pre applied adhesive is roughly as heavy as 14 um alu, so I could bump the filled plane alu to 20 um while still being lighter. And it should hold corrugations even better right?
The easiest to test with would be kapton with release liner but that is even more expensive than regular kapton.
I wonder if it would be possible to lay mylar / kapton on the ReMount glue and then cut it as if it was alu foil. Then spray the 3M 77, weed but then glue on top of say 20 um alu. Then cut say self adhesive 30 um alu and glue it on top of the mylar / kapton.
Or what if the 30 um acrylic adhesive is thick enough to act as electrical insulation by itself?
Interesting ideas!
You can for sure dry run the different configurations without the use of the SC5; just use scissors with smaller pieces than completed membranes.
Then corrugate them.
You can for sure dry run the different configurations without the use of the SC5; just use scissors with smaller pieces than completed membranes.
Then corrugate them.
I just got the 50 um aluminum tape. And while the tape + adhesive technically is close enough 50 um, the aluminum definently isn't.
I measured the resistance of the alu in some traces and based on that, it seems to be 25 um thick aluminum. Interestingly enough the adhesive is also thinner so the ratio of aluminum / weight is roughly the same of this tape vs the previously thicker 30 um self adhesive aluminum I've used.
This means that while tape is not useful as a single sided traces, it could be interesting with dual sided traces.
But since I still want 50 um aluminum tape I ordered again but this time from DigiKey. It is more expensive but the specification is very clear so I should be safe in getting what I have ordered 🙂
The newly ordered tape should have 51 um aluminum, 33 um thick acrylic adhesive.
I measured the resistance of the alu in some traces and based on that, it seems to be 25 um thick aluminum. Interestingly enough the adhesive is also thinner so the ratio of aluminum / weight is roughly the same of this tape vs the previously thicker 30 um self adhesive aluminum I've used.
This means that while tape is not useful as a single sided traces, it could be interesting with dual sided traces.
But since I still want 50 um aluminum tape I ordered again but this time from DigiKey. It is more expensive but the specification is very clear so I should be safe in getting what I have ordered 🙂
The newly ordered tape should have 51 um aluminum, 33 um thick acrylic adhesive.
erm would that not make it extreem heavy ? you got dual alu at places where its driven. arent you back to use lets say 6 or even 3 mic mylar.. then do whatever you want , but at least be sure it wont be shorting out ?
By the way if you need any i got huge rolls of 30 50 and 100 my alu, and they are as claimed. 50 much stiffer 100 almost impossible to cut.
rolls are 50 cm wide, or you can just buyb a roll yourself at https://aluminiumfolie.nl/
i use this for bass and mid panels... so i am not sure if you want to use such heavy foil for tweeter duty... to me that is a bad idea.
Did you measure at the same SPL when using thiner foil ? i was wondering. so if lets say 12 mic has more output but higher distortion, lower the input on that one to match the output of the other and compare. since higher output comes with higher distortion to begin with.
and last and i mentioned it but dont know if you took that into account or not. you are listending to a 30cm foil ? while you end up with maybe a 150 cm foil. if using heavy foil, you wont have much top end compared to lower end.. it does look better in the low end but it wont add to the total efficiency. you need low weight in your 30 cm version with a rising response then when you make it 150 it will level out. and distortion will be low since you got 5 times the surface area.
rolls are 50 cm wide, or you can just buyb a roll yourself at https://aluminiumfolie.nl/
i use this for bass and mid panels... so i am not sure if you want to use such heavy foil for tweeter duty... to me that is a bad idea.
Did you measure at the same SPL when using thiner foil ? i was wondering. so if lets say 12 mic has more output but higher distortion, lower the input on that one to match the output of the other and compare. since higher output comes with higher distortion to begin with.
and last and i mentioned it but dont know if you took that into account or not. you are listending to a 30cm foil ? while you end up with maybe a 150 cm foil. if using heavy foil, you wont have much top end compared to lower end.. it does look better in the low end but it wont add to the total efficiency. you need low weight in your 30 cm version with a rising response then when you make it 150 it will level out. and distortion will be low since you got 5 times the surface area.
If I'm using a solid fill then kinda, but not really as long as I use different thicknesses. Yes, there is dual alu at places where it is driven. And I never used that thin alu, that was @solhaga. The thinnest I have used is 14 um.
If we take a traditionally corrugated membrane with outside fill for stiffness:
The traces are only 3 mm wide which makes the fill take up most of the weight. But we can counterract that by using much heavier foil for the traces vs the fill. I have for example used 14 um alu for the fill, and 30 um alu for the traces.
But the above membrane has some wiggly distortion patterns that seem to go away if I use a heavier alu for the fill, 20 um. Or if I, instead of having gaps around the traces & 20 um foil, use a solid fill of 14 um foil.
And it just so happens to be that the 20 um fill with gaps for the traces, and the 14 um solid fill weigh pretty much the same within a few %. It is also nice that the filled variant has no aligntment needed, since there are no features to align, simplifying the design.
But still it is not as efficient as my gapped traced membrane with 20 um fill + 20 um traces on both sides. That is why I want to buy 50 um aluminum tape, such that a single side of that thick tape will be equivalent to dual sides of 20 um.
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Ooo, another nice source within the EU, thanks!
And about the thickness, keep in mind that the trace width is only 3 mm, where the magnet to magnet ctc is 10 mm. My first foils had 6 mm wide traces, like this, and 20 um thickness was a good compromise on weight and performance:
They are pretty efficient and can be cut from one sheet of aluminum since by area, 42 % of the foil is driven which is pretty good. And distoriton is pretty good also, as long as I don't push the xmax so I can't cross too low.
If I reduce the traces width from 6 mm -> 3 mm, then the magnetic field is far more linear so the distortion when pushed is way way lower. It is not even close, all the tall order distortion just goes away. But, like you say, the efficiency goes to hell which is no good to me. Or at least it does, if I use the same trace alu foil thickness.
But if I keep the alu fill at 20 um, but slightly more than double the thickness for the traces, then even though I'm using say 50 um foil for the traces, the actual weight of the membrane stays pretty much the same. It is still slightly heavier because fill area is larger, but only in the order of 15-20 % so not that significant.
When measuring SPL @ 1W I have been measuring at 0.5 m or more. And for distortion like you say there is a linear region, but the magic with having exactly 3 mm trace width given this exact magnet configuration is that the linear region is very big so there is no exponential increase in distortion like when I have 6 mm wide traces. So on high output vs low output it is pretty much that 10 dB increase in output has 10 dB more distortion.
Here is distortion for one of the 3 mm wide trace membranes, at -0 dB which is somewhere in the 5-10 W range @ 400 hz.
The increase is still pretty well behaved and not like a 6 mm wide traced membrane which instead looks like this. Where if I go above some xmax then the distortion skyrockets to unusable territory. Both of the following measurements are at the same SPL, and the rightmost measurment has 3 mm wide traces.
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So if weight is not a problem i would suggest making it a double foil, without useless weight (tape that is not used for output) so if you would design a coil and would flip it, so the left outer connection becomes the right one. the middle connections can be made like this so they overlap and can be soldered trough the mylar.
let one connection be longer (so you can see the back side of that coil) solder away the mylar clean with acetone, and solder both together. now you got a coil that is twice as long. now change the coil on the back to cover as much of the space thats within the coil of the front coil (with some overlap). and you got what you are looking for complete coverage but no weight is wasted. its all driven. and you might come closer to the output of the the thinner foil. except top end... you can fix that with lighter foil , if you want.. but you can also just use a sloppy crossover and compensate at the same time.
here a bass frame dual coil, its cool because the connection points becomes both outside of the foil... something that is a problem if you had these in the middle of a foil... anyway this one is 1:1 so they overlap as good as i could , while in your case you want to shift the coils so everything is covered , except in the middle of the magnet (maybe a false trace just for stability
here a bass frame dual coil, its cool because the connection points becomes both outside of the foil... something that is a problem if you had these in the middle of a foil... anyway this one is 1:1 so they overlap as good as i could , while in your case you want to shift the coils so everything is covered , except in the middle of the magnet (maybe a false trace just for stability
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You mean double foil as in coils on both sides of the kapton / mylar? Wouldn't I get the same result, if I used single sided coil but with twice alu thickness (assuming same alu thickness for the non driven area)? The single sided coil is kind of like two coils on top of each other, in parallel. With dual coils I could run them in series but in the end while the resistance would be different, the efficiency per watt would stay the same.
One benefit of dual sided coils would be thermal handling though, since they would have twice the surface area to dissipate heat.
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