Alesis GT Reference Manual page 25

The middle band is parametric and offers amplitude, frequency, and
bandwidth parameters as described next.
¥ 5 Band Parametric This is identical to the 3 Band Parametric but
offers two additional sweepable midrange stages with variable boost
or cut, frequency, and bandwidth. The following diagram shows the
relationship between three parameters.
The complex response of the 5 band parametric lets you compensate
for dead spots on a guitar's neck, or set up a very specific frequency
response.
¥ 11 Band Graphic The graphic equalizer can boost or cut any of 11
different bands (16 Hz, 32 Hz, 62 Hz, 126 Hz, 250 Hz, 500 Hz, 1 kHz, 2
kHz, 4 kHz, 8 kHz, and 16 kHz.
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