Hm, just found that the "vhb" tape I jused to fix the diaphragm to the frame is slipping and the tension in the diaphragm is gone. flappa-flappa-----
Seems like I have to get the "real stuff" from 3M, heir VHB tape should be suitable for this.
The idea of 4mm distance between diaphragm and magnets will be reduced to 2,7 in next built.
No point measuring frquency responce at this stage.
regards
Bent
Seems like I have to get the "real stuff" from 3M, heir VHB tape should be suitable for this.
The idea of 4mm distance between diaphragm and magnets will be reduced to 2,7 in next built.
No point measuring frquency responce at this stage.
regards
Bent
cutting tape
HI, The tape lasts a long time, I built my first full range planar 20 years ago and the tape is still in position and working! I used the wrong material for the membrane once, it became brittle and it was the tape that was holding it together. So you don't have to worry about the tape coming off!
I cut my tape using a small pair of scissors, up to now have cut 105 meters with no problems. I cut the tape in two pieces. It is a good idea to cut the tape as it increases the sensitivity at least twice. I no longer use the full width of the CPC tape.All my designs go down to 17Hz. I even used one as a subwoofer with my new Onkyo 3007 amp. I recommend you use 50 x 12.7 x 3 mm neo magnets any thicker are very dangerous, although my last design used 6 mm. I think this is the thickest you should use for safeties sake! I have just finished my latest full range planar using 6 mm neos, size60 x 40 cm. Will measure this using my TENMA sound level meter. I am positive this will go down to at least 17 Hz.If I could help in any way with 20 years experience don't hesitate to ask.HENRY.
HI, The tape lasts a long time, I built my first full range planar 20 years ago and the tape is still in position and working! I used the wrong material for the membrane once, it became brittle and it was the tape that was holding it together. So you don't have to worry about the tape coming off!
I cut my tape using a small pair of scissors, up to now have cut 105 meters with no problems. I cut the tape in two pieces. It is a good idea to cut the tape as it increases the sensitivity at least twice. I no longer use the full width of the CPC tape.All my designs go down to 17Hz. I even used one as a subwoofer with my new Onkyo 3007 amp. I recommend you use 50 x 12.7 x 3 mm neo magnets any thicker are very dangerous, although my last design used 6 mm. I think this is the thickest you should use for safeties sake! I have just finished my latest full range planar using 6 mm neos, size60 x 40 cm. Will measure this using my TENMA sound level meter. I am positive this will go down to at least 17 Hz.If I could help in any way with 20 years experience don't hesitate to ask.HENRY.
diaphragm slipping.
HI, Go to posting 41 and see pic of finished frp. I have found that using wood is best for diaphragm tightening. You can go round taking out all the kinks and ripples, and if it goes flappy in the future you can go round again etc etc. I usually make the distance between diaphragm and magnets 3 mm using neos and 2 mm using ferrites.If you use wood or mdf at 6 mm thickness this is perfect for the 3 mm gap. As I use 10 mm thick ferrites 12 mm wood is perfect for the gap. Hope this helps. HENRY
HI, Go to posting 41 and see pic of finished frp. I have found that using wood is best for diaphragm tightening. You can go round taking out all the kinks and ripples, and if it goes flappy in the future you can go round again etc etc. I usually make the distance between diaphragm and magnets 3 mm using neos and 2 mm using ferrites.If you use wood or mdf at 6 mm thickness this is perfect for the 3 mm gap. As I use 10 mm thick ferrites 12 mm wood is perfect for the gap. Hope this helps. HENRY
Sorry to hear that.
Are you using the same alu tape as båndsai??
You said that you got 4,3 ohm from 4 m (5 x 0,8 m). båndsai got 0,6 ohm from 5 meter!
Båndsai's findings would be consistent with a thickness of 0,03 mm (30 my), which I think I saw somewhere.
Heavy kitchen alu foil is 12 my ..... which is too heavy to use for high freq.
BR Baldin
This is how i cut my foil.It is not an easy task,but i sucseeded to cut 4,5mm and 3mm,rolls.
It was difficult to make an order at CPC in England.You have to send a mail ,and when it is confirmed, you get a mail and have to phone them to make a transfer of money.
I am working at a new projekt.I will post in "diy planarspeakers"
Have rebuilt my 20 year old first FRP design using MDF 12 mm thick have not used angle iron in the new design so it is much lighter and it looks better before covering with the red material which I used to hide the original design which was heavy and ugly.
I am also rebuilding 2 more older designs using my new membrane securing method. I have also found some old black poly only 1/100th of a mm thick. When I can found some more I will be rebuilding all my designs. This will keep my mind active!!?? Wish me luck, I'll need it.
I am also rebuilding 2 more older designs using my new membrane securing method. I have also found some old black poly only 1/100th of a mm thick. When I can found some more I will be rebuilding all my designs. This will keep my mind active!!?? Wish me luck, I'll need it.
new designs
I am in the process of re-designing and rebuilding all my full range planars about10 pairs+.
I have bought new membrane material, polyester (mylar) .004 mm thick this is quite brittle and easily ripped.
polythene .0024 mm thick which is more supple than the polyester.
I have also bought some magnetic tape 1.5 mm thick and I am in the process of building a centre speaker for my new amp.
I don't know yet whether this will be any good, because the tape is very weak.
I have ordered some other tape 3 mm thick. Hopefully this will be better!!
So I have plenty to keep me busy, wish me luck!!
No peace for the wicked.
I am in the process of re-designing and rebuilding all my full range planars about10 pairs+.
I have bought new membrane material, polyester (mylar) .004 mm thick this is quite brittle and easily ripped.
polythene .0024 mm thick which is more supple than the polyester.
I have also bought some magnetic tape 1.5 mm thick and I am in the process of building a centre speaker for my new amp.
I don't know yet whether this will be any good, because the tape is very weak.
I have ordered some other tape 3 mm thick. Hopefully this will be better!!
So I have plenty to keep me busy, wish me luck!!
No peace for the wicked.
I am in the process of re-designing and rebuilding all my full range planars about10 pairs+.
I have bought new membrane material, polyester (mylar) .004 mm thick this is quite brittle and easily ripped.
polythene .0024 mm thick which is more supple than the polyester.
I have also bought some magnetic tape 1.5 mm thick and I am in the process of building a centre speaker for my new amp.
I don't know yet whether this will be any good, because the tape is very weak.
I have ordered some other tape 3 mm thick. Hopefully this will be better!!
So I have plenty to keep me busy, wish me luck!!
No peace for the wicked.
You mean 1.5 mm width i hope
THE 3 mm Will be great for a planarNo 1.5 mm thick and 12.5 mm wide magnetic tape, the 3 mm thick tape is 50 mm wide. I will cut the 3 mm to size, when I have decided on the width I will use. The central planar I'm building at the moment has a gap of 4.5 mm between the magnets, I will probably build the same layout with no gap to find out the difference between the gap or no gap design. I don't think the magnetic tape is strong enough compared to ferrites or neo's. But we shall see!Keeps me out of mischief. I should finish the centre speaker today, then I will see if the design was worth it.
Planar...funny name
means 'plane', yes ?
joke aside, you could try with using 'surround'
I once built a big one with thin foam on both sides
Sorry for the chosen word, but I'm not sure that everybody knows the Heil ribbon... which isn't a ribbon in fact !
Please, do you have a small drawing or a pict to explain your approach ?
Hi there Henry: Googled-up density of materials you are interested in:
Polyester: 1.40g/cubic cm
Low Density Polyethylene: o.910 to 0.940 g/cubic cm
Medium Density Polyethylene: 0.926 to 0.940g/cubic cm
High Density Polyethylene: 0.930 to 0.977 g/ cubic cm
(there are other grades of HDPE, with varying densities)
(sources: answers.com and ides.com)
Hope this wil be of help in your continuing research into the permanent magnet planers, thanks for publishing your work. ...regards, Michael