Frequency response

Frequency response is a term used to define the performance or behaviour of a electronic or electrical signal device, as per its electrical output. Whether it be an audio or RF amplifier, a speaker, an tv antenna or any other electrical or electronic device, there are different needs.

Different needs for different applications

The frequency response of some devices are more complicated than the elementary functions. There can be several peaks or shapes in the attentuation-vs-frequency of some systems. An example where it is intentionally made, is a graphic equalizer, which many times can be set to compensate for an nonlinear frequency response.

Devices with various kinds of frequency response are useful in electronics applications. Examples to be mentioned are tone control circuits in audio amplifiers, EQ tuning in a video distribution amplifier that compensates for signal losses inherent in long cable runs and lowpass filters to minimize the harmonic (distortion) contents from a linear amplifier. A guitar amplifier has a limited frequency response because it has only one type of speaker and no tweeter. This gives a smooth guitar sound, especially to the common overdrive distortion sound.

For audio

Often when term frequency response is used it refers to stereo components, like speakers or amplifiers. The frequency response of a speaker amplifier usually has good wideband characteristics in the audio range, at low levels, but when an amplifier is loaded, i.e. higher volume, the performance in the low frequency range is changed and therefore the frequency response may behave non linearly. There are different criterias as to what is necessary for hi-fi audio. Generally, 20 - 20kHz is a standard criteria. However, as explained on the audio frequency page, also lower frequencies can affect the overall performance.