Recording Equipment User Manual

sound. Some types of lters (like the bass and treble controls on
your sound system) have subtle, gentle effects on a sound’s timbre.
Other types of lters have stronger and more dramatic effects, and
are frequently used as vital elements in the music-making process.
Strong lters include phasers, angers, and wah-type resonant
lters.
A graph showing what a lter does is called the lter’s frequency
response. The horizontal axis is frequency. The vertical axis is the
lter’s gain. A gain of “1” (unity) means that, at that frequency, the
output of the lter is just as strong as the input. A gain of less than
unity means that the lter’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 shows examples of the frequency response
characteristics of two common types of lters: (a) a lowpass lter,
which passes frequencies without attenuation up to a so-called
‘cutoff frequency’, and attenuates the frequencies above cutoff; (b)
a resonant lter, which emphasizes frequencies around the lter’s
‘center frequency’.
Both of these lter 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. The rst type is embodied in the moogerfooger MF-101
lowpass lter, and the second type is embodied in the MuRF..
There are eight separate resonant lters in your MF-105.
Figure 4 - Frequency responses of typical lters.