A ribbon tweeter is a type of loudspeaker driver designed to reproduce high frequencies. Instead of using the dome and voice coil found in a conventional tweeter, a traditional ribbon tweeter uses a very thin strip of conductive material suspended within a magnetic field.

The ribbon acts as both the diaphragm that moves the air and the electrical conductor carrying the audio signal. When an alternating audio signal passes through the ribbon, it interacts with the magnetic field and causes the ribbon to move backwards and forwards.

Because the ribbon is extremely thin and lightweight, it has very little moving mass. This allows it to respond rapidly to changes in the audio signal, making ribbon tweeters particularly well suited to reproducing high frequencies and fine musical detail.

A loudspeaker crossover determines which frequencies are sent to the ribbon tweeter. Lower frequencies are normally directed to a woofer or midrange driver, while the ribbon handles the upper part of the frequency range. The exact crossover frequency depends on the design of the loudspeaker and the capabilities of its drivers.

Ribbon tweeters can have different sound dispersion characteristics from conventional dome tweeters. The shape and dimensions of the ribbon can result in relatively wide horizontal dispersion combined with more controlled vertical dispersion, although this varies considerably between individual designs.

Traditional ribbon drivers have very low electrical impedance and often require a transformer to provide a suitable interface between the ribbon and the amplifier. Modern implementations can use different construction methods to overcome some of the practical limitations associated with traditional ribbon designs.

Ribbon tweeters are sometimes confused with planar magnetic tweeters and Air Motion Transformers. Although all three can use thin diaphragms and magnetic systems, they operate differently. A true ribbon tweeter passes the audio current through the ribbon itself, while planar magnetic designs normally use conductive traces attached to a separate diaphragm. An Air Motion Transformer uses a folded diaphragm that squeezes air from between its folds.

Ultimately, a ribbon tweeter performs the same basic function as other tweeters by reproducing the high-frequency portion of the audio signal. Its extremely lightweight diaphragm and distinctive operating principle make it an alternative to the dome tweeters commonly found in conventional loudspeaker designs.