Preserving the relative amplitude of each sound's harmonic components requires the use of drivers with exceptionally uniform frequency response. To achieve accurate response, THIEL drivers are designed to eliminate cone break-up, or diaphragm resonance in their operating range. In addition, electrical correction is employed for response irregularities.
-Aluminum domes and cones
THIEL employs aluminum as a diaphragm material in all of its tweeters and most of the cone drivers. Aluminum has much higher stiffness and compressive strength than conventional diaphragm materials, and therefore provides a broader range of resonance-free operation. The result is extremely clean and open reproduction with no ringing.
An additional benefit is that the aluminum's greater compressive strength causes virtually all the energy of a transient attack to be transferred to sonic output instead of being absorbed by the diaphragm itself. Shown below is the CS2.3 woofer, which uses an aluminum diaphragm.
Some of the circuitry in THIEL crossover networks is used to correct frequency response irregularities. As an example, the graphs below illustrate four frequency response measurements for the CS7.2's lower midrange driver: the ideal target response (A); the driver in cabinet response (B); the network response (C); and the final acoustic response (D) which is the sum of the driver and network responses. As can be seen, the actual response (D) matches the target response (A) very closely.
The inclusion of these additional network elements improves the overall speaker frequency response and ensures that the exact timbre of each specific sound will be true to the original, without the speaker adding colorations of its own.