PreSonus StudioLive 328AI - Manual (Page 27)

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4 System Configuration
4.2 Delay Systems
StudioLive ™ AI-Series Loudspeaker
Owner’s Manual
4.2.1 Delay Basics
Delay speakers allow you to run the main speakers at a lower volume, as they
relieve the mains of handling high- and mid-frequency content for part of the
space. As a speaker is pushed harder, the edges of its frequency response begin
to distort, so by easing the demands on the mains, delay systems increase
fidelity sonically, as well as mechanically. This also means that the front row
doesn’t need to be blasted just so the people at the back can hear the show.
The goal of distributed sound is to extend the intelligible range of the system,
without killing the front of the crowd with excessive level. As noted earlier, sound
travels much slower than electricity, so the audio coming out of the delay system
will arrive to the listeners before the audio coming out of the main system. Without
proper alignment, the multiple arrival times create confusion to the listener and sonic
definition is lost. Speech and beat transients become less intelligible. In large venues,
this can actually create a flam or echo effect. By delaying the audio going to side and
rear fills, you can create a cohesive listening environment for the entire audience.
It should be noted that frequencies in the sub-bass range of a delay
system do not require distribution. In fact, a delay system’s highpass
filter should be rolled up as high as 300 to 400 Hz to avoid sound going
back toward the stage as low frequencies become omnidirectional.
When placing delay systems, the main goal is to maintain intelligibility of the PA,
especially in the vocal consonant range (2 to 4 kHz). However, this goal is achieved
by overcoming different obstacles depending on whether you are indoors or
outdoors. In both situations, the delay system should be set where the main
system’s intelligibility falls apart. As with the main system, the placement of the
delay systems will determine how successfully you are able to achieve these goals.
Inside. Indoors, you are trying to overcome the direct-to-reverberant reflections.
The location of the delay system is dependent on the critical listening area
(typically just behind front-of-house). Your goal is to find where the direct
signal-to-reverberation ratio has reached about 50/50. At this point, the
reflections in the room are at an equal level to the direct sound of the PA, and
vocal intelligibility is lost. Listen for a lack of intelligibility in the vocals and
find the point at which the drums and rhythm section don’t feel tight.
A great way to find the best position for your delay speakers is to set up and
tune your main system and play audio through it. Play something similar to
what you will be mixing later. Set the level so that it is comfortable from the
front row. Walk backward away from the main system until you notice a lack of
clarity. This is the beginning of the space that will need delay-system coverage.