Dbx DriveRack PA2 Bedienungshandbuch PDF herunterladen (Seite 43)

Delay

There are two different delay module types available in the PA2, they are: the input (also known as pre or backline) delay

module and the output (also known as driver alignment) delay module.

The output delay modules (labelled HIGH, MID, and LOW) are used to time align loudspeaker drivers which require it. Typically,

driver alignment delay is only required when configuring a bi-amplified (2-way) or tri-amplified (3-way) system. Time alignment

delay is required because of the physical offset which exists between the different drivers within the loudspeaker system,

and when you bypass the internal passive crossover circuit in a speaker enclosure you must make up for these differences in

distance. Because of this physical offset, the sound emanating from each driver will reach the listeners’ ears at different times,

creating phase anomalies in the frequency regions where multiple drivers reproduce the same frequencies (the frequency

range in close proximity to the set crossover frequencies).

Driver alignment delays are included with speaker tunings, so when you select a specific model of bi-amplified main speaker

in the Setup Wizard, driver alignment delays will automatically be entered for you based on the model you selected. However,

depending upon where you place your subwoofers or the type of subwoofers used, you may need to enter a delay offset to

take them into account as well. If you place your mains directly on top of your subs or use stand mounts that mount your mains

above your subs, you shouldn’t have to worry about a delay offset between your mains and subs. If you’re not sure, take a

look at one of your speaker stacks from the side perspective and ask yourself, “is the woofer’s voice coil in my main speaker

physically aligned with the subwoofer’s voice coil?” You should be able to get a good idea if you may have to apply some delay

offset for your subs or simply reposition your mains on top of the subs, if possible. Note that small differences in distance

(e.g., a few inches) between low and sub drivers is negligible and should not be of any concern, due to the large size of these

low-frequency waveforms.

If your subs are placed off to the side of the stage or somewhere other than between the mains or under the mains

(anywhere not aligned with the mains when viewed from the side perspective), you will likely need to manually apply some

driver alignment delay. If you do need to apply driver alignment delay to compensate for sub placement, you can calculate the

difference in distance between the sub and “sweet spot” (the audience position which forms an equilateral triangle with the

main speakers) and the mains and sweet spot, then enter this value into the corresponding driver alignment delay (i.e., the

cabinet which is further forward will need to be “pushed back” or delayed). If the subs are located further back from the mains,

you will have to apply the delay to the mains. If the subs are located further forward than the mains, the driver alignment delay

will have to be applied to the subs.

The input delay module is used for a different purpose. Once your driver alignment delays have been dialed in, the input delay

module can be used to apply a slight delay to the entire sound system (that’s why it’s placed pre-crossover). By applying this

backline delay, the acoustic sound emanating directly from the instruments on stage (drums, guitar amps, horns, etc.) can

be positively reinforced by the sound system. To set the backline delay, measure or approximate the distance between the

instrument furthest back on stage (usually the drums) and the main speakers then enter this distance into the input delay

module (the PA2 allows you to enter the delay time setting in feet, meters, or milliseconds – no calculation required). Don’t

forget to take your driver alignment delays into account. For example, if you’ve placed your subs to the side of the stage and

delayed your mains to align them, the mains delay would need to be subtracted from the calculated backline delay. You can

also try simply dialing this in by ear, by standing in front of the stage and wirelessly adjusting the input delay LENGTH, using

the Mobile Control app, until the system sounds its best.

Delay Parameters

The Delay menus can be accessed by pressing the DELAY button. You will see a list of the available delays to select from. In

all cases you will at least see the INPUT DELAY and HIGH DELAY. If you’ve configured a 2-way system, you will also see a

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Dbx DriveRack PA2 Bedienungshandbuch Seite 43