MACKIE HR824 - Manual (Page 3)

3
INTRODUCTION
In short, all the complex interconnected
components in the system are designed to work
in harmony with each other to produce the best
possible sound.
The Transducers...
The monitors feature an 8.75-inch die-cast
magnesium frame woofer and a 1-inch viscous
edge-damped aluminum-alloy dome tweeter on
the front, and a 6-inch x 12-inch elliptical flat
piston passive radiator in the back.
The high-frequency driver is mounted on a
massive, acoustically non-resonant die-cast zinc
exponential waveguide which results in wide,
controlled dispersion of high-frequency sounds.
The unique passive radiator design provides a
smooth response down to 39Hz — an astounding
accomplishment for a cabinet of this size! And
since the radiator is producing most of the sound at
the lowest frequencies, there is very little distortion
from the woofer because its cone movement is
minimal at those frequencies.
The Cabinet...
The cabinet is made of high-density MDF wood.
An internal “H” brace further increases the strength
and rigidity (stiffness) of the box. An open-cell
adiabatic foam material fills the inside of the
box to absorb internal reflections and dampen
standing waves.
FR Series Power Amplifiers...
What better way to power the loudspeakers
than with our acclaimed FR Series “Fast Recovery”
power amplifiers. Our Fast Recovery design uses
low negative feedback, yet allows the amplifiers
to maintain low distortion and stability even
when driven into clipping.
The low-frequency amplifier produces up to
150 watts continuous (350 watts peak) before
clipping, while the high-frequency amplifier produces
up to 100 watts continuous (210 watts peak).
Thank you for choosing Mackie Designs’
HR824 Studio Monitors. We realize that monitors
are a critically important tool whether your appli-
cation is studio recording, audio/video post
production, hi-fi, or home theater. Knowing this,
Greg Mackie had a simple mandate: Design a refer-
ence monitor with a degree of accuracy and
versatility unmatched by any other in its size and
price category — or any size and price category
for that matter. The mandate was simple, but
accomplishing it was another story!
Investments in Excellence...
To accomplish the task at hand, Greg and the
New Product Development team realized that a
commitment was required in terms of new resources
and new equipment. So we recruited some of the
best speaker and acoustic engineers in the indus-
try to assist in the design of the HR824. And we
invested in some advanced (and need we say
expensive) measurement and analysis tools for
the design team to use.
The result? The HR824 Studio Monitors are
extremely accurate and versatile, loaded with
unique controls that allow you to fine-tune the
sound to match your individual environment
precisely. You’re gonna love these!
What are they? The Advantages...
The HR824 Studio Monitors are high-resolution,
two-way, bi-amplified, active monitors employing
a 6th-order Butterworth system with a built-in
rear-firing mass-loaded passive radiator. Whew!
There are many benefits to integrating an active
crossover, power amplifiers, and drivers into a
single cabinet, and we’ve taken full advantage of
these benefits in the design of the HR824.
• The crossover point is designed so that the
high and low frequency drivers are fed only
the frequencies they are best able to reproduce.
• The amplifiers are designed to provide
maximum acoustic output from the speakers,
yet minimize the danger of speaker damage
due to overdriving.
• In addition, the amplifiers’ gain and fre-
quency responses are individually
hand-trimmed to compensate for typical
manufacturing tolerances between the
drivers and produce a smooth frequency
response from 39Hz to 20kHz (
±
1.5 dB).
• The connecting wire between the amplifier
outputs and the drivers are kept to an
absolute minimum, so the damping factor of
the amplifier isn’t compromised by the
resistance of long speaker cables.
• The acoustic sum of the outputs from the two
drivers are optimized electronically, as well as
physically, so the amplitude response is unity
and the phase difference is minimal.
Tweeter
Woofer
Passive Radiator
"H" Brace
Power Amplifier/
Crossover Assembly
Figure 1. HR824 Cutaway side view