Originally posted by mzisserson
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Received my W6520R-4 drivers!
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Re: Received my W6520R-4 drivers!
Originally posted by Pete Basel View PostFeyz, have you seen the JBL paper by Gander "Moving-Coil Loudspeaker Topology as an Indicator of Linear Excursion Capability"?
It is the 3rd from the bottom here on this page:
http://www.harman.com/EN-US/OurCompa...yID=Scientific Publications
I'm not sure if any patents came out of that study.
http://cn.jblpro.com/pub/obsolete/4406.pdf
"LOW FREQUENCY DRIVER
The 162 mm (6.5 in) diameter LF driver has a filled
polypropylene cone which combines the smooth
response associated with polypropylene with the
resistance to breakup associated with pulp or lami-
nated materials. Linearity of the LF driver is the
result of careful attention to mechanical suspensions
as well as Symmetrical Field Geometry (SFGJ. SFG
reduces harmonic distortion by producing identical
magnetic flux fields on each side of the magnetic
gap. This ensures that the voice coil will intersect
equal flux lines for both positive and negative excur-
sions of the cone. A flux stabilizing ring placed
around the pole piece reduces the effects of mag-
netic flux field modulation. Overall, SFG reduces
distortion to about one-tenth the value found in
conventional magnetic structures.
A cast aluminum frame ensures mechanical integ
rity under the most demanding operating
conditions."
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Re: Received my W6520R-4 drivers!
Originally posted by feyzThanks for the impedance curve, it does show a curve indicating copper in the air gap, or very close to it.
ScanSpeak has SD, SD-1 and SD-2 motors. My understanding SD is an extended copper cap/sleeve on the pole piece and the earliest one. The foam surround paper and poly 7" mid-woofers had this motor, and also the 8" kevlar one 8555 ? and etc.
I don't know exactly who holds the patent to this motor design, but once I was searching in the patent database years back, I had found my way back into a 1970's patent that had this. I don't recall seeing a famous name like JBL, or Scan-Speak or Dynaudio, but I might have overlooked. It was old such that it only had the scanned patent, not the text version.
The JBL patent may be for a motor which has a thick ring on the base of the pole piece. This style was used in Peerless CSX. It is good for lower frequency but less effective in mid and high frequencies.
Later Scan-Speak drivers started using SD-1, the famous 18W\8545 carbon fiber/paper cone, and the Revelator mid-woofers for instance. SD-1, instead of copper sleeve on the pole piece, has two rings that sandwich a T shaped pole piece, plus a 3rd ring under the lower ring. It is not well known, but the patent for the motor that has two rings sandwiching a T shaped pole piece belongs to McIntosh. Scan-Speak's SD-1 having a 3rd ring below the lower ring differentiates itself from McIntosh's patent, and has a patent of its own.
The Scan-Speak SD-2 motor is the SD motor (pole piece cap/sleeve) plus a sleeve on the top plate side of the air gap. Used in their tweeters only I believe. I don't know if they have a patent for this, other than a design patent. The Dayton RS tweeters have same design, making me believe Scan doesn't hold a patent on this, maybe only design patent.
Seas Excel drivers are basically McIntosh design sandwiched T poles.
Now I read all kinds of variations starting to be used by different manufacturers, like the ring on the base of the pole piece and sleeve on the pole piece and etc. All good!
It is the 3rd from the bottom here on this page:
http://www.harman.com/EN-US/OurCompa...yID=Scientific Publications
I'm not sure if any patents came out of that study.
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Re: Received my W6520R-4 drivers!
I will have a project started before too long, depends on how some other results from a recent excrement hitting the turbine event turns out.
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Re: Received my W6520R-4 drivers!
I haven't got anything going yet with my pair. Too many other projects in the works to finish first.
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Re: Received my W6520R-4 drivers!
Originally posted by Jeff B. View PostThat's a very nice tweeter, by the way. I think you will really like it.
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Re: Received my W6520R-4 drivers!
"Eclipse" is the Meniscus house brand.
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Re: Received my W6520R-4 drivers!
Originally posted by kenny_k View PostKnow what you mean. ;)
Waiting for a pair to put together with a SB tweet (http://meniscusaudio.com/sb-sb26stcn4-p-1206.html) for a 2-way.
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Re: Received my W6520R-4 drivers!
Originally posted by bigfishe View PostAny progress on this build?
Waiting for a pair to put together with a SB tweet (http://meniscusaudio.com/sb-sb26stcn4-p-1206.html) for a 2-way.
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Re: Received my W6520R-4 drivers!
Originally posted by PWR RYD View PostBut don't Usher and Scanspeak midbass drivers cost much more than this $70 driver??? ;)
They seem like a very good driver overall and I am anxious to see some designs with them. Not my cup o' tea methinks, but there will be some great designs with it for sure and most importantly it is great to see an american player in the game.
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