dbx DriveRack PA2 Owner'S Manual Download

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6�

Raise the mixer’s main output faders until the INPUT CLIP LEDs on the PA2 just begin lighting.

7�

Now, go to each amp channel and slowly raise its attenuator until the amp channel’s clip LED just begins to light.

8�

Go into one of the PA2’s limiter modules. Turn the limiter on and slowly lower the THRESHOLD parameter until the
corresponding amp channel’s clip LEDs just stop lighting. Don’t lower the limiter THRESHOLD parameter too far, just
far enough to hold the signal level just below the clip point of the connected amplifier. Do this for each active pair of
DriveRack outputs (i.e., High, Mid, and Low).

9�

Turn down the pink noise and main output faders on the mixer then power down the system.

10�

Reconnect your speakers to your amps.

11�

Power up the system, ensuring to power up your amps last.

The system is now optimized to provide the loudest levels possible, with adequate headroom between devices, and with the
least amount of noise. Now, sit back, play your favorite music through the system, and slowly raise your mixer’s main output
faders. When the mixer’s main faders are set to unity gain (0), the system will now provide the highest sound pressure level
it is capable of. If the system is not loud enough when the mixer is set to unity gain, this is an indication that the system is
inadequate for the application, so you may want to consider amplifiers with greater output power – but still within the power
rating of your loudspeakers – or additional speakers and amplifiers. Most loudspeaker manufacturers recommend an amplifier
which provides 1.5 to 2 times the rated RMS power of the speaker. If the sound system is too loud when the mixer’s main
faders are set to unity, this indicates that you have more power than is required for the application and you can simply turn
down your mixer’s main output faders until the desired “performance level” is achieved.

4. Balance The System’s Frequency Response

Now that the crossover is configured, the loudspeakers are all in phase, the gain structure of the system is calibrated, and the
limiters are set, it’s time to balance the system’s overall frequency response by fine-tuning the amplifier attenuators. This step
is not always necessary, but can often help smooth out the system’s frequency response before applying any system EQ. You
can perform this “balancing” while listening to your favorite reference music and do it by ear. The music you choose to use
for reference should contain full-bandwidth audio and should be something you have spent much time listening to and are
extremely familiar with.

Since the gain structure is already set and the limiters calibrated, you will not want to raise your amplifier attenuators, as we’ve
already determined when we set the gain structure, setting them any higher will cause the amplifiers to clip. Instead you will
want to lower the amp attenuators for whichever frequency range (i.e., low, mid, or high) is too loud. For example, if the system
has too much midrange, turn down your mid amp attenuators. If the system has too much high end, turn down the high amp
attenuators. The goal is to achieve a somewhat balanced system.

HiNt:

Before making any final amp attenuator adjustments, you may want to take note of the position of all amp

attenuators or mark their settings. This way you can retain the reference amp attenuator settings above which the amplifiers
will clip. You may also want to mark or take note of any adjusted settings if you do end up making any final amp attenuator
adjustments to further balance the system.