CoDrive™ Products
CoDrive™ NeoSym™ competition sub (US patent # 6,778,677)
Why a “conventional” driver from CoDrive?
In the course of developing the CoDrive subwoofers, I found their performance was being limited by the speaker motor's power capacity. In order to generate the force needed for my CoDriver to function properly in a small sealed box, a 4" voice coil was operating too close to it's thermal limit. A bigger motor was clearly needed.
"There's no replacement for displacement" is an old hot rodding truism. Of course the high cost of tooling speaker motors bigger than 4" is the reason they have seldom been made. It would drive the cost of manufacturing an already expensive driver into the stratosphere.
That's when it
occurred to me that two speaker motors mounted face to face, in a
"push-pull" arrangement, would create a motor with double the power
capacity. And since they must work in opposite phase, with one coil moving into
it's magnet structure while the other coil was moving out of an identical
magnet structure, it would create a motor with a perfectly symmetrical Bl curve
and cancel any DC offset. Just the thing for a high performance subwoofer!
Another aspect of
typical speaker construction that I have never liked is that when a speaker
voice coil fails due to thermal overload or mechanical bottoming, it’s not a
part that can be easily replaced. Some pro-audio speakers can be repaired by
fitting a new basket/cone/voice coil assembly onto an existing magnet
structure, but a much cleaner and more cost effective fix would be to design
the speaker so the voice coil alone could be easily replaced.
After many hours pushing a mouse in front of a CAD screen I came up with a simple and logical design that solved all the problems. I machined a couple of prototypes to see if it would really work. The answer was a resounding YES, so a U.S. patent application was filed.
After consulting magnet suppliers, coil winders and spider manufacturers, I made the decision to go ahead with tooling a double 2.5" coil motor. This would have the equivalent winding area of a 5" voice coil, 25% more than the single 4" coil that was limiting my CoDriver, but not having more coil mass than necessary for that application. Of course, this was going to require some special parts not normally available from speaker component suppliers, so I got to work on the tooling necessary to make production quantities of the unique parts. An injection mold was made, casting patterns were tooled, a spider was tooled, magnets were spec'd and purchased, coils were wound, and steel was machined.
Now that the patent has been granted (U.S. #6,778,677, Repairable Electromagnetic Linear Motor for Loudspeakers and the Like), the CoDrive "Neo-Symmetrical" (NeoSym ) linear motor is in production! I finally had a motor that could stand up to the rigors of powering my compound driver with headroom to spare!
Any "electro-dynamic linear motor" that is powerful enough to drive two speaker cones in a small sealed box (as a friend once said) "will pound the piss" out of one cone. A speaker with a field replaceable voice coil is well suited for the unique demands of automotive SPL competition. It makes a lot of sense to build a "conventional" automotive subwoofer powered by this motor.
A limited number of CoDrive™ Neo-Sym™ 15” auto subwoofers will be available to qualified individuals in 2006. These subs are designed to race! They are the first production competition subs that can truly be rebuilt by the end user. With the CoDrive Neo-Sym auto sub, if you break it, you can fix it. A fried voice coil assembly (armature) can be replaced in a few minutes!
By summer of 2007, a variety of standard voice coils will be available to optimize the driver for more conventional automotive, home and pro applications.
Preliminary specs and pricing:
voice coil
diameter: 2.5", number of voice coils: 2, winding length and DCR: wound to
spec, magnet material: NdFeB, xmech: 3" total
15" NeoSym competition subwoofer (beta version) $699
Armature (voice
coil assembly) $79
Limited quantities are available for qualified competitors. If you would like to be considered for beta testing please send us your resume.
Neo-Sym™ subs to be in limited production by spring ‘06.
please call 541-447-4529 for availability. (Mon-Fri 9am-4pm west coast time)
warranty: All of the components
used in the manufacture of this product are of the highest quality available.
We guarantee all CoDrive™ products
to be free from defects in materials and workmanship for a period of one year
from the date of purchase. Because this product in intended for use and abuse
that goes beyond the scope of normal operation (i.e. competitive dB drag
racing), burned or mechanically damaged voice coils are not subject to warranty
compensation. All replacement or repair for warranty claims will be at our sole
discretion. Factory repair service is available for all CoDrive™ products. Specifications subject to change
without notice.
Ron Coffin 2/25/06
