About Thiel
Stereophile's Editor John Atkinson Interviews Designer Jim Thiel
Stereophile's March '98 issue featured an insightful interview with Jim Thiel written by Editor John Atkinson. Here is an excerpt of that interview.
John Atkinson visited the THIEL factory last year for a tour and to
sit down with Jim to discuss his design philosophy. The results were
published in the March 1998 issue of Stereophile.
The interview begins with a discussion about Jim getting started in the
speaker business and the choice of designing dynamic speakers. After
designing and marketing two bookshelf style speakers starting in 1976 "I
started thinking a lot more seriously about not just making a good product,
but making a product that I hoped would be better than any others available," said
Jim. "I started giving a lot of thought to the inherent limits and
problems of dynamic speakers and identified one area: the phase and time
distortion that's introduced by typical high-order crossover networks,
and the fact that the drive-units are not mounted coincident with each
other."
After designing and marketing two bookshelf style speakers starting
in 1976, "I started thinking a lot more seriously about not
just making a good product, but making a product that I hoped would
be better than any others available."
-Jim Thiel
The birth of Coherent Source
Jim goes on to explain the beginnings of his Coherent Source design by
using phase correct first-order electrical networks and drivers mounted
along a sloped baffle for proper time performance, a basic design principle
that is at the core of every THIEL product built today.
Jim also discusses driver design and how THIEL's drivers have evolved
over the years from using modified OEM drivers to today's completely
THIEL designed and built units. This means that "we can implement
designs that are more exactly what I desire," says Jim. And that
speeds up development time and allows for a lot more experimentation
to get the design perfected. "we'd actually made 77 different experimental
versions of the CS7's lower-midrange unit. We were able to go through
so many iterations that we can end up with a design that is much closer
to what we want." And what Jim wants-and has achieved-are speakers
with lower distortion, greater dynamics, and more accurate tonal balance.
Evolution of design
The coaxial driver mounting, short coil/long gap motor design, and the
use of metal diaphragms in the latest models are also discussed as an
ongoing refinement of those basic principles Jim dedicated himself to
20 years ago. "All of our products have incorporated incremental
advances in various aspects of their design [over the years]: improvements
in the quality of crossover components, improvements in the drivers,
improvements in the cabinet construction," says Jim.
Measurements and listening
One of the more interesting aspects of the interview is Jim's comment
on how he correlates measurements with listening. "I view the
ear as a measurement tool. And you can use it to evaluate the differences
between the sound of loudspeaker designs just as usefully as you can
use a computer to evaluate objective differences," says Jim. "I
can make a change to the crossover circuitry and measure the effect
that has on performance, then go and listen to what effect it has on
the subjective performance. And I've done that tens of thousands of
times over the years. You can build up quite an understanding of the
correlations between measurements and subjective impressions."
And what goals does Jim seek to achieve in future THIEL products? "One
thing that would be ideal is for all the drivers in the three- or four-way
system to be coincident. So you would have not only a coaxial unit, you
would have a triaxial unit, or four drivers that are mounted coaxially.
That would be an improvement, if you could pull off such a thing," says
Jim. "There are always improvements to make, with better diaphragm
materials, lower-distortion, higher-quality components, better cabinet
construction methods. We just have to see what new ideas we come up with
in the future."
