Frequency response - a two-dimensional graph that shows how unevenly amplified signal depending on the frequency.If we talk about low-frequency amplifiers, ie, the acoustic equipment, the response determines the naturalness and natural sound reproduction.
audio distortion are linear and nonlinear.To include non-linear change of the output waveform, and to linear - uneven amplification while maintaining its shape.
amplitude response of the amplifier has a twist: the division on the x-axis, on which a range of frequencies in the audible range, has a logarithmic grading, - the higher the frequency, the smaller the intervals between the divisions.This method of display is justified peculiarities of human hearing, that distinguishes the modulation, the smaller the higher the tone.
ideal frequency response would look like a straight horizontal line.But, as is known, create a power absolutely uniformly and identically reproducing the whole spectrum, even at a relatively narrow range of audible sound, is almost impossible.It's all about the characteristics of the electronic components that make up the circuit (as amplifier, semiconductor or tube, and auxiliary, capacitance and inductance).Each transistor chip or lamp have their own response.Only careful adjustment provided for the construction of the entire device, to compensate for non-ideality of the individual components.This can be achieved and the selection of items, and a deep negative feedback, which reduces both linear and nonlinear distortion.
Since the ideal frequency response can not be, then we can speak only about the extent to which it deviates from a line parallel to the abscissa axis.It is considered that the change of gain within three decibels for human hearing is not critical, however the frequency band is defined as the interval between the intersection of a line lying on the 3 dB below the peak gain (typically in the region of 1000 Hz) from the line features in the field of so-called "endbends ".Do not assume that the frequencies below and above the boundaries of the frequency range "not passed", just hear them significantly worse.
Remove the response of the amplifier, you can use simple devices (oscilloscope and audio frequency generator), or by using an accurate voltmeter.It needs to input devices of the same signal value, for example, 200 mV, and the different frequencies and to measure the intensity of the output, causing the data on the graph.On RADIOZAVOD taken to adjust frequency response using a special all-wave generator is applied to the input of the entire range, and the meter, demonstrates a chart on the screen.In terms of production it turns much faster to achieve results.
loudspeakers serving as payload for the amplifier, in turn, have their own characteristics, and they are also far from ideal.To compensate for the total frequency response of the amplifier design includes devices such as the tone controls or a multi-band equalizer.Equipment Hi-End class does not have such settings, their frequency response so carefully set up and agreed to fully complete the AU, which, in addition to the volume knob and toggle switching, and other control devices are required.
