Understanding Tweeter Design and Construction
There are many considerations when upgrading the audio system in a car, and one of the most overlooked aspects is the tweeter. The way a tweeter is shaped and the material with which it is constructed plays a large role in how the music will sound. The tweeter is the part of the speaker that reproduces the high-frequency sounds in music, namely the guitars, vocals and horns. Tweeters also help to give audio more body, so the sounds are not trapped near floor level, where they can be difficult to hear and enjoy.
Several factors are considered in the choice of a tweeter for any particular speaker, namely cost and the quality of sound that is produced. The challenge lies in keeping the tweeter lightweight without compromising its ability to hold up under high-volume conditions. A tweeter also needs to have good damping, which means it quits vibrating quickly when the music stops playing. To achieve these goals, tweeters can have varying shapes and be made from different materials, the details of which are explained below.
Shapes of Tweeters
- A tweeter’s shape determines the efficiency of high-frequency response. A variety of shapes are used to obtain the best results when compared to cost.
- The cone type tweeter is the cheapest to manufacture and is the design found most often in car audio systems. Most standard tweeters of this type are “whizzers”, which are tweeters that are placed inside the woofers to maximize high-frequency response. The drawbacks of this type include an inefficiency to properly distribute sound, and poor overall audio quality.
- The semi-dome type tweeter, also known as a balanced-type, is a cone-shaped tweeter with a dome built inside of it. Both parts are about the same size and are found in lower-end speakers. The materials used for this type of tweeter are softer and provide a lower profile, which limits damage through improper mounting or poor handling. This tweeter type is found mostly in coaxial speakers, although it is also seen rarely in component speakers as well.
- A dome tweeter offers the best dispersion of high-frequency sound and a wider range with which to work when setting the system up. The details of the speaker will include the dome’s size. Larger dome tweeters require higher levels of power to operate properly and deliver the best results.
The materials used in the construction of tweeters can include aluminum, silk, titanium and beryllium. The majority of materials fall into three basic categories.
- Synthetic films are light in weight and tolerant to humidity, which is a must in a car interior. They require minimal power to operate and are often found in low-cost audio system speakers. Unfortunately, tweeters made from films have limited damping capabilities and do not produce high-quality sound output.
- Silk is a textile material used in tweeter construction. It offers the advantage of a more refined, lifelike sound result and is often used in home audio systems. High-power silk tweeters are reinforced with other synthetics to provide superior damping results, allowing for high volume, accuracy and smoothness.
- Tweeters built with blended metals output loud and crisp high-frequency sound. Aluminum is most commonly used for this purpose, as it will produce highs that can be distinguished from bass and noise from the road. Another approach is titanium, which is extremely lightweight and produces very accurate highs without the roughness that can occur with aluminum tweeters. It is expected that manufacturers will expand into more exotic combinations of metals and ceramics as time goes on.
Making the Right Choice
When it comes down to making a choice between silk and metal, the type of car and driving style makes a difference. For example, if the car is driven mostly with the windows open allowing in a lot of road noise, metal tweeters are the better choice. A quiet auto interior calls for silk tweeters to produce the most natural-sounding audio.
Separates and Coaxials
Tweeters can be separate from the speaker‘s woofer or completely integrated. This can be a crucial difference when placing speakers inside of a car, as the higher the tweeter’s position, the more efficiently it can disperse the sound. It is important to note that a cheap tweeter is not going to provide quality sound output regardless of where it is placed.
Some types of speakers, such as three-way and four-way models, have multiple tweeters, which further separates sonic sound frequencies. In the case of a three-way speaker, there can be a driver for the mid-range, which gives the music a warmer quality, or a supertweeter, which offers superior response in the high-frequency range.