Welcome! Need support, you got it. Or share your ideas and experiences.
Return to Planar Speaker Asylum
107.211.82.25
In Reply to: RE: Difference between 3.7 and 3.7i's posted by Roger Gustavsson on April 04, 2014 at 12:15:10
Yes, the lower mass midrange was mentioned in one of the reviews. (Of course, reviews are sometimes wrong.) Agree that they probably wouldn't reduce the foil thickness, what with the cost of neodynium magnets.
Follow Ups:
Josh wrote:
” Yes, the lower mass midrange was mentioned in one of the reviews. (Of course, reviews are sometimes wrong.)”Reviewers are often told facts that they never check. If we believe the reviews written over the years, Magneplanar drivers would have no moving mass at all. Truth is that it is still the same Mylar and wiring in most cases. Round wires or flat wires does not change the mass. I do not know why people believe the mass is less while going from round to rectangular wires. For exemple, the wiring of the 3.6 mids are about 2 gram, Mylar also 2 gram (but it is a part of the bass section...) and then some glue. Compared to an electrostatic this is a lot of moving mass.
For comparsion, the largest section of the Tympani IVa mids, the wiring is 0.5 gram and the Mylar 0.3 gram.
Here a picture of the T-IVa mids: http://www.twin-x.com/groupdiy/albums/userpics/IMG_0353.JPG
Edits: 04/05/14
I am still dreaming of a graphene conductor on a thin kaladex in a neodymium powered push pull driver that would be able to be as fast as an electrostat without its output limitations and arcing.
Unfortunately, the commercial graphene is still too high in resistivity to compete with Aluminum conductors since the lower density of the graphene does not compensate for the much higher resistance, so the practical driver would still end up with a higher mass with graphene. Even if you make the whole diaphragm from graphene it would still be heavier to conduct the same current as Al.
Perhaps interesting, headphones using graphene driver:
http://arxiv.org/abs/1303.2391
That is very cool
I have no way of knowing whether the reviewer was correct. They certainly aren't always. But I think Satie did a good job of describing the trades here. Assuming you want to maintain the Bl product, the wiring can't play a role unless you can find more powerful magnets that fit the budget. But of course there are other ways of reducing the mass. It's pure speculation until you look!
Interesting figures, BTW.
Outside of the glue wires and mylar there is the damping layer. You can use a lighter gauge membrane if you go for a stronger polyamide rather than a regular polyester. More expensive, but that is what BG did. The damping material would be something to look at. Maybe something that dries less stiff would make for lower final tension or for less mass if you can spray less of it and still get enough damping.
I tried pricing Neo magnets for the ribbon tweeters thinking that I could improve their efficiency but it was absurdly expensive. I think it was $300 just for the magnets. Then I had to have someone weld on stiffening strips on the tweeter frame so it won't buckle with the extra magnetic force. It all got very expensive very quickly.
Yeah, neo magnets are crazy, aren't they.
I recall reading a BG white paper in which they said they used Kapton on their smaller drivers because their small surface area required superior heat resistance.
Pic is of Kapton repeating unitKapton is a polyimide, BG used kaladex a cousin of PET, PEN Poly ethelene naphthalate (instead of terephthalate) good for high temp (180C continuous) film with 2.5X tensile strength of PET (of cola bottles fame) and great flex recovery. Makes for excellent capacitor film too. Also used for flexible printed circuit boards.
Edits: 04/04/14 04/04/14
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: