Speck Electronics EQ16 - Manual (Page 28)

When using the EQ16 it is important to understand the relationship
between the maximum input level, the maximum output level, and the
boost/cut controls. The maximum input level for the EQ16 is +28 dBu,
and the maximum output is +28 dBu. The EQ16 can not exceed these
maximum input or output levels without incurring distortion. The
equalizer channels do not have any gain, so any signal that goes in will
come out at the same level.
When interfaced to professional audio equipment that produces a
nominal level of +4 dBm for a 0 VU indication, the Model EQ16 has a
headroom margin of 24 dB.
The margin of headroom for the above examples apply only when the
boost/cut controls on all three bands are set flat (0 center position).
When any boost/cut or any combination of boost/cut are "boosted", the
margin of headroom is decreased. When any boost/cut or any
combination of boost/cut are cut, the margin of headroom is increased.
The preceding statements only apply to the frequency(s) that have been
selected with the respective frequency sweep controls. When the EQ
bypass switch is disabled, the maximum output of the EQ16 is only
limited by the maximum output of your device.
For the sake of the following discussion, only "boosting" the boost/cut
controls will be discussed since "cutting" on any band or combination of
bands can only increase the headroom margin for its respective
channels.
The boost/cut controls can be thought of as a gain increase or decrease
control for the specific frequency(s) that have been selected. For
example, if your signal had a low frequency signal content and this
signal was boosted 12 dB, this would leave you 12 dB of headroom for
that low frequency signal before the output would clip or cause
distortion.
Although 12 dB of headroom is not much, it still will result in a clean
undistorted signal.
formula:
Boost/Cut
24
Headroom and
Boost/Cut
formula:
+28 dB max output minus +4 dB = 24 dB of headroom
+4dBu reference level plus 12 dB boost minus 28 dBu maximum
output = 12 dB headroom.
Chapter 4 Operation Section