sound. Some types of filters (like the bass and treble controls on your sound system) have subtle, gentle effects on a sound’s timbre. Other types of filters have stronger and more dramatic effects, and are frequently used as vital elements in the
A graph showing what a filter does is called the filter’s frequency response. The horizontal axis is frequency. The vertical axis is the filter’s gain. A gain of “1” (unity) means that, at that frequency, the output of the filter is just as strong as the input. A gain of less than unity means that the filter’s output is attenuated at that frequency, while a gain of greater than unity means that the output is actually greater than the input.
Figure 4 - Frequency responses of typical filters.
Figure 4 shows examples of the frequency response characteristics of two common types of filters: (a) a shelving lowpass filter, which passes frequencies without attenuation up to a so-called ‘cutoff frequency’, and attenuates the frequencies above cutoff; (b) a resonant filter, which emphasizes frequencies around the filter’s ‘center frequency’.
Both of these filter types are widely used in contemporary music performance. Each of them has its own distinct sound, a large part of which is directly related to the shape of its frequency response graph. A cut-off filter is used at the lowest effected frequency of the MF105B. The remaining seven filters are all resonant filters.
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