Understanding Tweeter Technology
By Igor Levitsky
A look at the pros and cons of the major tweeter types.

The moving-coil loudspeaker driver was patented by Rice and Kellogg in 1924 and since then it remains largely the same in principle. Through the years engineers have worked hard to develop alternative solutions to reproduce sound. The first ribbon transducer was patented in the early 1920s, for example, followed a few years later by a patent for the electrostatic loudspeaker.

In the early years of audio, power amplifiers had tubes with very low output capabilities; usually they produced only several watts. To compensate, speakers had to have high sensitivity to deliver useful sound levels. Woofers required a large cone area with large voice coils to handle power and produce high output. Tweeters however, needed small and light-moving systems to achieve high sensitivity and extended high-frequency range.




All early tweeters were actually compression drivers that had stiff phenolic or aluminum diaphragms loaded on a horn. While such designs possessed very high sensitivity, sound quality was largely compromised. It didn't truly become the primary goal of speaker design until 1958, when Edgar Villchur developed what was considered the first high-fidelity speaker, the Acoustic Research AR-3.

To get it all right in one speaker design is a huge task. Driver design requires a precise and skillful balancing between components, motor topology and materials. And there has always been the pursuit of clarity and resolution, which has led to expensive and exotic designs.

Dome
Villchur's invention is still the most common tweeter type; probably about 95 percent of all speaker systems use dome tweeters. This tweeter is very well developed, but there are still some engineers that are working on new shapes, materials, motors and waveguide designs.

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