Edge wound market hype

[robertbartsch]

Are edge wound coils an industry standard now?

This used to be a marketing point with Lansing stuff 40 years ago when no one else did this. They used to say edge wound coils produce more effecient drivers with more dynamic range, I suppose.

Anyway, obviously the JBL professional series still does this today but, I wonder about everyone else, since new speaker offerings in the market place today are, well, disappointing.

[Mr. Widget]

JBL still does it on all of their better offerings. Other brands use this technique as well and Dynaudio and a few others use hexagonal VC wire. The point is to get as much wire in the smallest space...


Widget

[robertbartsch]

Interesting - THX.

Originally, the VC wires were all copper but later they changed to aluminum. I suppose aluminum has less electrical resistence; what impact did that have?

I read the history behind the switch away from Alnico magnets in the Forum section below that was interesting. I did not see anything similar on voice coil developments, however.

[Mr. Widget]

Originally, the VC wires were all copper but later they changed to aluminum. I suppose aluminum has less electrical resistance; what impact did that have.There never was a change over. JBL still uses both. They use aluminum for it's low weight and copper for it's higher power handling capability. The designers will choose the type of wire along with the length of the coil, number or turns, type of former etc. to achieve a desired result.

BTW: Copper has lower resistance than aluminum and silver has even lower resistance.


Widget

[jcrobso]

JBL pioneered so many innovations, over the years many other brands have adopted some of them.
The are several companies the make drivers with edge wound Voice Coils today.
In the 50s & 60s JBL speakers were the only one with this, they also pioneered large voice coils. I remember Electro Voice adds 30 years ago stating the 2 1/2" voice coils were better and now they have large voice coils.
John

[Titanium Dome]

I remember Electro Voice adds 30 years ago stating the 2 1/2" voice coils were better and now they have large voice coils.
John

Yes, it was a variation on a theme: It's not the size of your voice coil, but how you use it. :rotfl:

[Ian Mackenzie]

Yes, it was a variation on a theme: It's not the size of your voice coil, but how you use it. :rotfl:

Is that why some drivers for the auto sene are called strokers?:D

I personally find the differential drive designs more interesting..you know push pull.:p

[scott fitlin]

Is that why some drivers for the auto sene are called strokers?:D

I personally find the differential drive designs more interesting..you know push pull.:pI, personally, I am into " Horn Loading" My GF likes it too! :bouncy:

[robertbartsch]

JCROBSO:
JBL pioneered so many innovations, over the years many other brands have adopted some of them. The are several companies the make drivers with edge wound Voice Coils today. In the 50s & 60s JBL speakers were the only one with this, they also pioneered large voice coils. I remember Electro Voice adds 30 years ago stating the 2 1/2" voice coils were better and now they have large voice coils.
John

******

Well, my new Altec VOTT system (circa 1973) had 3" edge wound voice coils and Alnico V magnents, so - weren't these inovations true for both Altec and JBL?

I thought the promotional flyiers I used to collect from both manufacturors at the time alluded to the fact that these construction techniques "were" a patented process.

Since patents typically run for 15 years, I assume (i) JBL and Altec licensed the patent technology and (ii) the patents on these ran out some time during the mid 1970s but that would be a guess on my part.

I thought the original patents on edge-wound coils were held by Bell Labs or Western Electric but I could be wrong. I checked the historical information on this site from both Altec and JBL and they allude to many important inovations but I did not see any discussion on edge wound coils which I beleive were the most significant inovations in "modern" transducer design.

I'm sure the promotional material from both companies in the early 1970s discussed the background for the edge-wound coils including who originated the concepts (Bell Labs or Western Electric) but I can't re-size the files listed on our cite here.

[jcrobso]

JCROBSO:
JBL pioneered so many innovations, over the years many other brands have adopted some of them. The are several companies the make drivers with edge wound Voice Coils today. In the 50s & 60s JBL speakers were the only one with this, they also pioneered large voice coils. I remember Electro Voice adds 30 years ago stating the 2 1/2" voice coils were better and now they have large voice coils.
John

******

Well, my new Altec VOTT system (circa 1973) had 3" edge wound voice coils and Alnico V magnents, so - weren't these inovations true for both Altec and JBL?

I thought the promotional flyiers I used to collect from both manufacturors at the time alluded to the fact that these construction techniques "were" a patented process.

Since patents typically run for 15 years, I assume (i) JBL and Altec licensed the patent technology and (ii) the patents on these ran out some time during the mid 1970s but that would be a guess on my part.

I thought the original patents on edge-wound coils were held by Bell Labs or Western Electric but I could be wrong. I checked the historical information on this site from both Altec and JBL and they allude to many important inovations but I did not see any discussion on edge wound coils which I beleive were the most significant inovations in "modern" transducer design.

I'm sure the promotional material from both companies in the early 1970s discussed the background for the edge-wound coils including who originated the concepts (Bell Labs or Western Electric) but I can't re-size the files listed on our cite here.
Bell labs has done tons of research but many time just stops the project and goes on to something else.
Wire wrap was a Bell labs concept but they didn't use it, then IBM started using it with great success, later Bell started using wire wrap.
When talking about the dark ages of sound (AKA the1920's) Jim Lansing was involved it this process, who did what is now some times hard to truly find out. John

[Steve Schell]

An edge-wound voice coil has an improved "space factor" compared to a multilayer round wire coil. Bell Labs claimed the advantage to be about 27% in their late 1920s literature. Their original 555W compression driver used rectangular aluminum wire of about .002" by .014" wound on edge to make the voice coil. An edge-wound coil is also stiffer mechanically and less prone to warping out of shape.

Maximizing the space factor would seem to be an important goal. Achieving high gap flux density is expensive, for one thing. Increasing the gap width a bit to accomodate a less space efficient coil would require quite a bit more magnet to restore the same flux density, as the reluctance of the air gap is a square of the width of the gap.

Having said all that, it happens that most of my all time favorite drivers, i.e. the Lansing and RCA prewar field coil theatre units, all have round wire voice coils; go figure. Rudy Bozak was a pioneer in fitting edge wound aluminum coils to Cinaudagraph cone drivers in the late 1930s. Edge wound coils didn't come into common use in cone drivers until after the war, when Western Electric's new line featured them and Jim Lansing used them in the new Altec and JBL designs.

Aluminum wire is used mostly in high frequency driver voice coils, due to its low weight. As I recall, aluminum wire of a given size has 70% of the conductivity of copper but only 1/3 the mass. Often the aluminum is clad with copper, about ten percent by cross section, to permit easier and more reliable connections to the voice coil leads.