Frequency response refers to how a system, such as an audio device or a filter, reacts to different frequencies of input signals. It is typically represented as a graph showing the output amplitude at various frequencies, helping to understand how well the system reproduces sound or signals across the audio spectrum. In audio engineering, frequency response is crucial for ensuring that music or speech sounds clear and balanced. A flat frequency response means the system reproduces all frequencies equally, while a colored response may enhance or diminish certain frequencies, affecting the overall sound quality. Understanding frequency response is essential for optimizing equipment like speakers, microphones, and equalizers.