dbx DriveRack PA2 - Manual (Page 47)

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Limiter
Limiters are used to set a ceiling on the signal level, preventing the signal from exceeding a predetermined threshold. For this
reason, they are used to prevent the overdriving of equipment. Limiters are compressors with high ratios (typically, a ratio of
around 10:1 or higher). The ratio controls in the PA2 limiter modules are fixed at infinity:1. In live PA sound systems, limiters
can be used just before the amplifiers to squeeze the last bit of level out of the sound system and protect your loudspeakers
by preventing amplifiers from clipping.
The limiter modules in the PA2 are post-crossover, meaning they can function as band-limited limiters. This allows you to limit
the LOW, MID, and HIGH outputs independently. For example, you could apply limiting on the signal feeding the subwoofer
amplifier without affecting any of the higher frequencies being sent to the main speakers. This has the additional benefit of
making any such limiting less noticeable.
The limiter thresholds will automatically be set for you when you run the Setup Wizard and select your amplifiers or powered
speakers from the tuning list. If tunings aren’t listed for your amplifiers, check the ever-growing online database using the
DriveRack PA2 control app to see if they’ve been added. If tunings cannot be found for your amps, select the NOT LISTED
option. Note that the limiters will not be set when selecting the NOT LISTED option for your amps. Therefore, the limiters will
need to be calibrated manually if you wish to use them to protect the system. See ‘Manual System Optimization Tips’ on
page 18 for more information on manually calibrating the limiters.
The PA2’s limiters are dbx PeakPlus™ type limiters. They use RMS detection, which provides very musical and natural limiting.
They also utilize some functionality from the dbx PeakStopPlus™ type limiters, in that they offer a soft clipping function which
helps by rounding out the transients (peaks). This provides additional protection and prevents the system from becoming
dull and lacking punch when limiting occurs. These PeakPlus™ limiters have an overshoot of 3 dB, meaning it is possible for
transients to exceed the threshold by up to 3 dB.
Limiter Parameters
The Limiter menus can be accessed by pressing the
LIMITER button. You will see a list of the available limiters to select from.
In all cases you will at least see the HIGH LIMITER. If you’ve configured a 2-way system, you will also see a LOW LIMITER
for the LOW outputs. If you’ve configured a 3-way system, you will see an additional MID LIMITER for the MID outputs. Turn
and press the
DATA wheel to select the desired limiter module. Turn the DATA wheel to scroll through the list of parameters.
Press the DATA wheel to edit a selection. When in a limiter menu, pressing and holding the LIMITER button for approximately
2 seconds will advance to the next limiter module, wrapping around through the available modules.
• LIMITER [ON, OFF]
Turns the selected limiter module on or off.