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Placement

WARNING: Installation should only be done by 
an experienced technician. Improper instal-
lation may result in damage to the equip-

ment, injury or death. Make sure that the loudspeaker 
is installed in a stable and secure way in order to avoid 
any conditions that may be dangerous for persons or 
structures.

The HD1521 speaker is designed to sit on the floor 

or stage. It may also be pole-mounted via the built-in 
socket on the bottom of the cabinet. Be sure the pole 
is capable of supporting the weight of the HD1521. The 
HD1521 may also be flown horizontally or vertically via 
its 12 integrated fly points.

Check to make sure that the support surface (e.g., 

floor, etc.) has the necessary mechanical characteristics 
to support the weight of the loudspeaker(s).

When pole-mounting loudspeakers, be sure that they 

are stabilized and secured from falling over or being 
accidentally pushed over. Failure to follow these precau-
tions may result in damage to the equipment, personal 
injury, or death.

You can create a horizontal array by placing the cabi-

nets side-by-side. However, you should have a good un-
derstanding of the relationship between the splay angle 
(the angle between the facing sides of the cabinets), 
the on-axis power, and frequency cancellation effects 
between cabinets.

When two cabinets are positioned vertically side-

by-side, the actual splay angle is 20º (determined by 
a 10º angle on each cabinet side). As the splay angle 
increases toward the angle of horizontal coverage (80º 
for the HD1521), the on-axis power decreases, but the 
frequency response becomes smoother as the comb-fil-
tering effects (caused by the interaction in the area of 
double-coverage) decrease.

As with any powered components, protect them from 

moisture. Avoid installing the loudspeaker in places 
exposed to harsh weather conditions. If you are setting 
them up outdoors, make sure they are under cover if you 
expect rain.

Room Acoustics

The HD1521 loudspeakers are designed to sound neu-

tral; that is, to reproduce the input signal as accurately 
as possible.

Room acoustics play a crucial role in the overall per-

formance 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 hol-

low 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 table 
or stand designed to handle the weight of the 
HD1521.

•  Position the loudspeakers so the high-frequency 

drivers are 2 to 4 feet above ear level for the au-
dience (make allowances for a standing/danc-
ing in the aisles audience). High frequencies 
are highly directional and tend to be absorbed 
much easier than lower frequencies. By provid-
ing direct line-of-sight from the loudspeakers to 
the audience, you increase the overall bright-
ness and intelligibility of the sound system.

•  Highly reverberant rooms, like many gymna-

siums 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 reflections, such as putting carpeting on 
the floors, closing draperies to cover large glass 
windows, or hanging tapestries or other materi-
als 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? Mak-
ing the sound system louder generally doesn’t 
work because the reflections become louder, 
too. The best approach is to provide as much di-
rect sound coverage to the audience as possi-
ble. 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 Contour EQ is a great way to 

compensate for some of these issues.

Owner’s Manual

Owner’

s Manual

Summary of Contents for HD1521

Page 1: ...HD1521 OWNER S MANUAL 2 Way High Definition Powered Loudspeaker...

Page 2: ...evice not expressly approved by LOUD Technologies Inc could void the user s authority to operate the equipment under FCC rules 20 This apparatus does not exceed the Class A Class B whichever is applic...

Page 3: ...with all applicable federal state and local regula tions We strongly recommend the following rigging system practices Documentation Thoroughly document the mounting rigging design with detailed drawi...

Page 4: ...Full Range Power Cords Power Cords Powered subwoofer plays the low frequencies Powered subwoofer plays the low frequencies Mixer HD1521 reproduces all frequencies above the subwoofer s crossover point...

Page 5: ...the Contour EQ circuit The LED next to the switch will light to indicate that the EQ is on Use this switch to engage or bypass the EQ or toggle it repeatedly while listening carefully to judge the EQ...

Page 6: ...dspeaker make sure that the voltage of your unit listed above the IEC AC receptacle is the same voltage as your local AC mains supply Use only the power cord supplied Also disconnecting the plug s gro...

Page 7: ...ome 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 plac...

Page 8: ...ng via its fly points NEVER attempt to suspend the HD1521 by its handles Rigging Design Practices Rigging a loudspeaker requires determining 1 The rigging methods and hardware that meet static shock d...

Page 9: ...ns carrying the heat away In order for this convection cooling to work efficiently it is important to provide adequate airspace behind the loudspeaker When positioning the HD1521 we recommend leaving...

Page 10: ...Tech Support department at 1 800 898 3211 Mon day Friday during normal business hours Pacific Time to explain the problem Tech Support will tell you where the nearest factory authorized service cente...

Page 11: ...akers See page 4 for a visual example of daisy chaining There is a limit to how many you can daisy chain together A general rule is to maintain a load impedance ten times or more than the source imped...

Page 12: ...iver sensitivity and amplifier power Measured with pink noise free field at 1 meter before limiting Power Amplifiers Low Frequency Power Amplifier Rated Power 700 watts rms 1400 watts peak Rated THD 0...

Page 13: ...25 in 463 5 mm Rear Width 11 82 in 300 2 mm Depth 18 81 in 477 8 mm Weight 80 lb 36 kg Mounting Methods Floor mount pole mount or fly via 12 integrated M10 mounting points using M10 x 1 5 x 37 mm for...

Page 14: ...1 100 10 1 1 3 Octave Response dB SPL 2 83 V 20 100 1000 20000 110 100 120 70 80 90 Horizontal Vertical Frequency Hz Directivity Index dB Directivity Factor Q 20 100 1000 20000 20 10 1 Frequency Hz Fr...

Page 15: ...he Warranty Period to the Company at www mackie com support or by calling LOUD technical support at 1 800 898 3211 toll free in the U S and Canada during normal business hours Pacific Time excluding w...

Page 16: ...Road NE Woodinville WA 98072 USA United States and Canada 800 898 3211 Europe Asia Central and South America 425 487 4333 Middle East and Africa 31 20 654 4000 Fax 425 487 4337 www mackie com E mail s...

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