dbx 1066 - Manual (Page 12)

8
Operating controls
PeakStopPlus™ Threshold (+) LED Indicator - This LED illuminates when the output signal exceeds the level set
by the PeakStopPlus™ LEVEL control indicating that PeakStopPlus™ limiting is occurring.
Figure 4 illustrates the protective action of the PeakStopPlus™ limiter. The signal with the thin line weight rep-
resents an unaltered input signal. As you can see, peaks of the input signal exceed the clamping level. The signal
with the heavier line weight represents the output signal. The peaks of the input signal which exceeded the
clamping level are not allowed to exceed this level at the output. This instantaneous protective action is invalu-
able for driver protection in speaker systems and for digital recording where it is desirable to record as “hot” as
possible, while still avoiding the disastrous result of running out of headroom. Following this clamping action,
Intelligent Predictive Limiting™ takes over, typically within 5ms, as long as the input signal continues to exceed
the PeakStopPlus™ threshold. This program limiter quickly attenuates the input signal to a level safely below the
clamping level, typically 2 dB lower than the clamping level. The PeakStopPlus™ level control is calibrated to
this lower level, so if an absolute ceiling is required, set the level 2 to 3 dB below the front panel setting.
As implied by the name, the attack and release times of the Instantaneous Transient Clamp™ are zero, while the
Intelligent Predictive Limiting™ attack and release times are program-dependent. That is, for larger excursions
over the threshold, the attack time speeds up, and for smaller excursions over the threshold, the attack time
slows down. Similarly, for large excursions over the threshold which cause more PeakStopPlus™ gain reduction,
the release time increases and is roughly proportional to the amount of gain reduction that occurred.
So, as you can see, dbx’s exclusive PeakStopPlus™ is a technically advanced and superior limiting scheme for
unrivaled system protection.
Time
Output Signal
Input Signal
Output Signal
Intelligent Predictive Limiting™
Release Time Attack Time
}
2 dB Typically
Absolute ceiling of the Instantaneous
Transient Clamp™
Intelligent Predictive Limiting™ Level
Figure 4: Protective Action of the PeakStopPlus™ Limiter