Which part is NOT one of the basic components of a Compression Driver?

The correct choice is the frequency filter, as it is not considered one of the basic components of a compression driver. A compression driver primarily consists of a diaphragm, a phase plug, and a magnet, which together work to convert electrical signals into sound.

The diaphragm is a crucial element that vibrates to produce sound waves, while the phase plug is designed to optimize the sound wave propagation and minimize distortion. The magnet provides the necessary magnetic field that interacts with the diaphragm, allowing it to move and create sound.

In contrast, a frequency filter is not an intrinsic part of the compression driver itself but rather a component that can be used in audio systems to manage and shape the frequency response of the sound being produced. While it plays a significant role in audio processing, it does not belong to the core components that define how the compression driver functions.