Installation manual

Community S-Series - Operation and Installation Manual - Page 40
dB greater in intensity than another, but will not be identified as the location that the sound
is coming from, if it arrives later than the lower intensity source.
This effect can be used to make underbalcony, overbalcony, and other delayed
loudspeakers acoustically ‘disappear,’ drawing the listener’s attention to the stage rather
than to the ancillary delay speaker. The idea is to first find the correct delay time that will
align the output of the ancillary loudspeaker with the output of the primary source, then to
increase the delay time of the ancillary loudspeaker to take advantage of the effect.
If the correct delay time is accurately identified within a range of one to two milliseconds,
the additional delay required to take advantage of the Haas Effect can be as little as two to
three milliseconds. The exact value should take into account the overall distance between
the two sources. Greater distances require slightly longer additional delay times in order to
compensate for variances in the velocity of sound as the temperature in the environment
changes.
Why not equalize by listening? After all, the end product is sound!
That’s true, but you’re probably not going to listen to swept sine waves, you’re more likely
to be listening to music. Even if you’ve trained your hearing to a very fine degree and you
possess perfect pitch, you can easily miss room resonant modes if the music you’re
listening to is in one musical key, and the room resonance happens to lie outside of that
key.
While some rooms exhibit broad resonant peaks that are readily detectable by listening,
others have quite narrow ones that can be easily missed. Typically, the bandwidth of room
resonance is often close to one-third octave, hence the development of the third-octave
equalizer. Unfortunately, most rooms aren’t cooperative enough to exhibit resonance that
falls precisely on ISO frequency centers, which makes the third-octave equalizer an
imprecise correction tool.
Even if a room resonant mode does fall on an ISO frequency center, its resonant frequency
will shift upwards when the room fills with patrons and the volume of air is reduced by the
displacement of solid bodies. An FFT type analyzer will let you see this effect, and a
parametric equalizer will allow you to adjust for it. With an FFT you can even use music as
your ‘test tone’ to continually measure the changes in the room response during a
performance, because a two-port FFT set to take continual measurements in the transfer
function mode doesn’t care what the signal is; it’s just as happy resolving music as it is
resolving pink noise, swept sine waves, or other sources. Noise just happens to provide
much faster results, because of its broadband nature.
RIGGING AND MOUNTING S-SERIES ENCLOSURES
One of the most important tasks the installer faces is the rigging and mounting of the
loudspeaker system. S-Series loudspeakers have been designed with rigging and mounting
in mind; thus, there are numerous ways to safely and easily install S-Series loudspeakers in
optimal locations in the venue.
SAFETY FIRST!
There is no way to overemphasize the importance of safety. But we’ll try. The kinetic
energy of an 80 lb. loudspeaker enclosure dropping from 30 feet and contacting a concrete
floor is enormous. The loudspeaker will be traveling at a speed of about 35 miles per hour
at the time of impact. Imagine if you were seated under it. You might have a better
chance of surviving a dynamite blast.
If you do not have knowledge of safe rigging practices and experience in applying them,
contact a qualified rigging contractor to design and carry out the installation! Rigging that
is improperly installed is like a time bomb; sooner or later it will fail, with the potential to
cause serious injury, paralysis, dismemberment, or loss of life. Even if no one is directly in
the line-of-fall of a failed suspension system, the panic that might ensue could in itself
cause multiple deaths. Do not take chances!