Mackie HD1221 Car Speaker User Manual


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Room Acoustics
The HD1221 loudspeakers are designed to sound
neutral; that is, to reproduce the input signal as
accurately as possible.
Room acoustics play a crucial role in the overall
performance of a sound system. Here are some
additional placement tips to help overcome some typical
roomproblemsthatmightarise:
• Avoidplacingloudspeakersinthecornersof
a room. Doing so increases the low frequency
output and can cause the sound to be muddy
and indistinct.
• Avoidplacingloudspeakersagainstawall.This,
too, increases the low frequency output, though
not as much as corner placement. However, this
is a good way to reinforce the low frequencies,
if so desired.
• Avoidplacingthespeakersdirectlyona
hollow stage floor. A hollow stage can resonate
at certain frequencies, causing peaks and dips
inthefrequencyresponseoftheroom.Itis
better to place the loudspeakers on a sturdy
stand designed to handle the weight of the
HD1221.
• Positiontheloudspeakerssothehigh-
frequencydriversare2to4feetaboveear
levelfortheaudience(makeallowancesfora
standing/dancingintheaislesaudience).High
frequencies are highly directional and tend to
be absorbed much easier than lower
frequencies.Byprovidingdirectline-of-sight
from the loudspeakers to the audience, you
increase the overall brightness and
intelligibility of the sound system.
• Highlyreverberantrooms,likemany
gymnasiums and auditoriums, are a
nightmare for sound system intelligibility.
Multiple reflections off the hard walls, ceiling,
and floor play havoc with the sound. Depending
on the situation, you may be able to take some
stepstominimizethereections,suchas 
putting carpeting on the floors, closing
draperies to cover large glass windows, or
hanging tapestries or other materials on the
walls to absorb some of the sound.
However, in most cases, these remedies are not
possibleorpractical.Sowhatdoyoudo?
Making the sound system louder generally
doesn’tworkbecausethereectionsbecome
louder, too. The best approach is to provide as
much direct sound coverage to the audience
as possible. The farther away you are from
the speaker, the more prominent will be the
reflected sound.
Usemorespeakersstrategicallyplacedsothey
areclosertothebackoftheaudience.Ifthe
distance between the front and back speakers
is more than about 100 feet, you should use a
delayprocessortotime-alignthesound.(Since
sound travels about 1 foot per millisecond, it
takesabout1/10ofasecondtotravel100feet.)
KeepinmindthattheVOICINGMODEswitchisa
greatwaytocompensateforsomeoftheseissues.See
page 7 for more information.
10
HD1221
HD1221
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