Received my W6520R-4 drivers!

[kenny_k]

Re: Received my W6520R-4 drivers!

Any progress on this build?

Know 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.

[Jeff B.]

Re: Received my W6520R-4 drivers!

Know 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.

That's a very nice tweeter, by the way. I think you will really like it.

[kenny_k]

Re: Received my W6520R-4 drivers!

That's a very nice tweeter, by the way. I think you will really like it.

Chosen based on reviews of your Sopranos. First used in my Poor Man's Line Arrays.
Thank you Jeff.

[bigfishe]

Re: Received my W6520R-4 drivers!

So this is an eclipse woofer?

[bkeane1259]

Re: Received my W6520R-4 drivers!

"Eclipse" is the Meniscus house brand.

[isaeagle4031]

Re: Received my W6520R-4 drivers!

That's a very nice tweeter, by the way. I think you will really like it.

Ha exactly the tweet I am ordering to go with as well. Should have it done by InDIYana. It may even make its way into Bens contest with a bit of an unusually "round" enclosure

[PWR RYD]

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.

[bigfishe]

Re: Received my W6520R-4 drivers!

Darn this cold weather!!!

[johnnyrichards]

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.

[Pete Basel]

Re: Received my W6520R-4 drivers!

Thanks 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!

Feyz, 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.

[johngalt47]

Re: Received my W6520R-4 drivers!

Here is a pic of one Docere...just the baffle though since they were built using PE's cabs.

[ligs]

Re: Received my W6520R-4 drivers!

Feyz, 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.

JBL has many woofers using Symmetrical Field Geometry (SFGJ. An example is the woofer used in JBL 4406.

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."

[Wushuliu]

Re: Received my W6520R-4 drivers!
Not grumpy at all. I just don't drink the juice. Honestly, too, far less than an ideal conditions to just fidelity. Yes, it plays loud. The endorsement from Jeff helps the cause but I do think it better perform like a mo-fo if it's going to be a value at $70.....Starting with high Le, a Qts over .4, and an 85dB eff is not a good start. Not grumpy just skeptical. I also look at a sense of value. I want a $70 driver that sounds like a $100 driver. That is value. A $70 driver that sounds like a $70 driver just runs with the pack... Now: If it can offer an application specific benefit that it will have some market-share. Otherwise it's just another driver and lawdy knows we gots lots o' them.

Funny to read these posts again after all this time. Whatever $70 competition to this driver there may have been back then (skeptical given Jeff's own assessment at the time)... are now gone or far more expensive. This Eclipse is now - if not then - the only ~$70 driver of this caliber.