User Manual

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11 Resources
11.7 Using Output Delay
StudioLive™ Series III
Owner’s Manual
In large venues that push the limits of the Front-of-House system’s coverage, using
delay speakers distributed throughout the room, each delayed to the main system,
allows you to create listening zones for more even coverage and better intelligibility.
Sound travels at a rate of 1,130 feet per second (with some variation due to
temperature, humidity, and elevation). Therefore, it takes 1.1 ms for sound to travel
one foot. For example, it takes about 11 ms for sound to travel 10 feet. So if you are
aligning your Front-of-House system is 10 feet from your drum kit, you need to delay
the signal going to that system by 11 ms.
There are professional software products that can calculate the exact alignment
times, but with a little math and little careful listening, this can be dialed in without
extra accessories.
11.7.1 Front-of-House
In a small venue with a relatively small stage, both the main speaker system and the
acoustic level of guitar amps and the drum kit on stage can be heard by listeners
in the audience. This can reduce the intelligibility of the speaker system because,
for example, the mic’d snare signal and the acoustic snare signal are arriving at the
listener’s ear at different times. This is where output delays come in.
The first thing you will need to do is to find the loudest instrument on the stage. In
general, this is the snare drum, but it could be the guitar amp, so let your ears do the
deciding.
1. Measure the distance from the snare drum to the mid-frequency drivers of your
main Front-of-House system and multiply it by 1.1 (if measured in feet) or 0.34 (if
measured in meters).
2. On your StudioLive mixer, select the Main mix and set the Output delay to the
result of your calculation.
3. Bring up the level of the snare channel on your mixer to unity and have your
drummer play single hits on the snare, about one hit every second. Make sure he
or she plays at the level they will play during the performance.
4. Use your Main mix level to set the level on the Front-of-house system as closely
to the acoustic level of the snare drum as possible.
5. Listen closely to the speakers and the snare and make minor adjustments to the
output delay until the attack times sound as coherent as possible.
11.7.2 Delay Systems
In most situations, a PA system relies on a main speaker system, positioned at the
front of the room, to reproduce audio for the entire performance space. As a result,
the level of the system is considerably louder at the front of the room then it is at the
mix position.
In situations where sound must be reproduced outside of the main system’s
optimum range, well-placed delay systems can extend the intelligibility of the
front-of-house system. By creating listening zones throughout the room, your front-
of-house system only needs to be loud enough to cover the front of the room. As a
result, you can lower the mains level, give the front-row listeners’ ears a break, and
get better fidelity from your speakers.
When placing delay systems, place delay systems where the main system’s
intelligibility falls apart as it is overcome by environmental obstacles:
Inside. Indoors, you are trying to overcome the direct-to-reverberant reflections.
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 P.A., and vocal intelligibility is lost.
Outside. Outdoors, you are trying to maintain level as the noise floor of the
crowd begins to be at equal level to the P.A. in the intelligibility range. At
this point, the main system needs more support in order to deliver the same
perceived loudness as you get further from the source.