Shure DP11EQ - Manual (Page 15)

14 English –
AGC Leveler
Definition: The AGC leveler (AGC stands for Automatic Gain Control) automatically lowers or
raises the signal level for sounds of varying loudness in order to create a more consistent volume.
Application: The leveler can be used for podium and lectern microphones, where it is desirable
to maintain a constant volume level when the talker may be moving back and forth from the
microphone. The leveler detects a lower level coming from the talker when they are farther away, and
compensates by gradually raising the gain. When the talker stops, the AGC gain will remain constant.
If the talker then talks too close to the microphone, the AGC will gradually reduce the gain.
For the AGC-leveler, the parameters and controls function as follows:
AGC Select Button. Click on this button to select the leveler. Click a second time to bypass.
THRESHOLD. The threshold (
Ê
) determines the minimum input signal level for the leveler to
activate. For input signals below the threshold, the gain is unity. For signals above the
threshold, the gain is the minimum of the setting determined by the ratio or the maximum gain
line (maximum gain, +12 dB). To prevent the possibility of gain increase in a feedback-prone
system, the AGC should be used with the threshold and hinge at the same settings, so that only
gain reduction will take place. To adjust the threshold, click and drag the “T” box at the top of the
graph, or click on the
↑
and
↓
buttons of the THRESHOLD field.
RATIO. The ratio line (
Ë
) pivots around the hinge, determining the amount the leveler adjusts
the signal level toward the hinge.
ATTACK. The attack controls how fast signal levels moving away from the hinge are adjusted.
DECAY. The decay controls how fast signal levels moving towards the hinge are adjusted.
AGC HINGE. The hinge (
Ì
) sets the desired output speech level of the leveler. The hinge is a
pivot point which determines whether a signal level is lowered or raised. Signal levels below the
hinge (between the threshold and hinge) will be raised, while signal levels above the hinge will
be lowered. To adjust the AGC Hinge, click and drag on the red “H” box at the bottom of the
graph, or click on the
↑
and
↓
buttons of the AGC HINGE edit box.
Maximum Gain Line. A +12 dB gain limit helps prevent excessive noise modulation or
acoustic feedback problems for low-level signals. This gain limit is indicated by the maximum
gain line (
Н
).