Editing Tweeter (section)

== Professional sound applications ==
Tweeters designed for sound reinforcement and musical instrument applications are broadly similar to high fidelity tweeters, though they are usually not referred to as tweeters, but rather as "high frequency drivers". Key design requirement differences are: mountings built for repeated shipping and handling, drivers often mounted to horn structures to provide for higher sound levels and greater control of sound dispersion, and more robust voice coils to withstand the higher power levels typically encountered. High frequency drivers in PA horns are often referred to as "[[compression driver]]s" from the mode of acoustic coupling between the driver diaphragm and the horn throat.

Various materials are used in the construction of compression driver diaphragms including titanium, aluminium, phenolic impregnated fabric, [[polyimide]] and [[PET film (biaxially oriented)|PET film]], each having its own characteristics. The diaphragm is glued to a voice coil former, typically made from a different material from the dome, since it must cope with heat without tearing or significant dimensional change. Polyimide film, [[Nomex]], and glassfibre are popular for this application. The suspension may be a continuation of the diaphragm and is glued to a mounting ring, which may fit into a groove, over locating pins, or be fastened with machine screws. The diaphragm is generally shaped like an inverted dome and loads into a series of tapered channels in a central structure called a [[phase plug]], which equalizes the path length between various areas of the diaphragm and the horn throat, preventing acoustic cancellations between different points on the diaphragm surface. The phase plug exits into a tapered tube, which forms the start of the horn itself. This slowly expanding throat within the driver is continued in the horn flare. The horn flare controls the coverage pattern, or directivity, and as an acoustic transformer, adds gain. A professional horn and compression driver combination has an output sensitivity of between 105 and 112&nbsp;dB/watt/meter. This is substantially more efficient (and less thermally dangerous to a small voice coil and former) than other tweeter construction.