MACKIE M800 - Manual (Page 14)

14
In order to match the output bandwidth with
your particular speaker system, the M•800 am-
plifier has a tunable
LOW CUT FILTER. The
frequencies are clearly marked along the knob’s
travel:
• Fully counterclockwise, the frequency is be-
low 10Hz, effectively bypassing the filter.
• Center detent is 35Hz, labeled TYPICAL,
since few woofers actually go below that.
• 3/4 of the way up is labeled STAGE
MONITOR, 100Hz, perfect for, well,
stage monitors (they seldom reproduce
below 100Hz; besides, it prevents low fre-
quency “leakage” into the house).
• Fully clockwise is labeled 170Hz.
So, grab your woofer’s spec sheet and find
the low roll-off spec. Then set the M•800’s
LOW CUT FILTER at the same frequency.
If you do this correctly (and make sure the
meters are happy), you’ll never again see your
woofer moving sporadically without audible
signal. Your system will play louder and
cleaner, and you may never blow another
woofer again!
CH
1
1 CHANNEL
CH
2
SPEAKER OUTPUTS
+
– –
+
MONO BRIDGE
BAL/UNBAL
MONO
BRIDGE
OFF ON OFF ON OFF ON
120 VAC 60 Hz
1500 WATTS
CONSTANT DIRECTIVITY
HORN EQ /AIR EQ
LOW CUT
FILTER
170 Hz OFF
4.5k Hz
6k Hz 2k Hz
AIR EQ
100 Hz
STAGE
MONITOR
TYPICAL
35 Hz
TYPICAL TYPICAL TYPICAL TYPICAL
STEREO
(MONO BRIDGE)
800 WATTS
4 OHM LOAD MIN.
400 WATTS CH
2 OHMS LOAD MIN.
THRU
LOW CUT
FILTER
INPUT INPUT
THRU
170 Hz OFF
4.5k Hz
6k Hz 2k Hz
AIR EQ
TYPICAL
35 Hz
CONSTANT DIRECTIVITY
HORN EQ /AIR EQ
CHANNEL 2
BAL/UNBAL
AMP MODE LIMITER
SERIAL NUMBER MANUFACTURING DATE
RISK OF ELECTRIC SHOCK DO NOT OPEN
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REMOVE COVER.
NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
CAUTION
AVIS: RISQUE DE CHOC ELECTRIQUE — NE PAS OUVRIR
THE FOLLOWING ARE TRADEMARKS/REGISTERED TRADEMARKS OF MACKIE DESIGN INC.: "MACKIE", "FR SERIES", & THE "RUNNING MAN" FIGURE
CONCEIVED, DESIGNED, AND MANUFACTURED BY MACKIE DESIGNS INC • WOODINVILLE
WA • 98072 • USA • MADE IN USA • PATENTS PENDING • COPYRIGHT ©1999
100 Hz
STAGE
MONITOR
Low Cut Filter Frequency Response
You can use the THRU jack
as an input, if necessary,
since it’s wired in parallel
with the other input con-
nectors.
You can also use the
1/4" TRS INPUT jacks as THRU jacks. Simply
connect the 1/4" TRS INPUT jacks on the first
amplifier to the TRS 1/4" INPUT jacks on the
second amplifier using 3-conductor shielded
cables with TRS plugs on both ends.
Warning: If you are using a
balanced input to the first
amp, do not use TS unbal-
anced connections to feed
other amplifiers. This will
unbalance the input con-
nections of your first amp by grounding pin 3.
LOW CUT FILTER
Every woofer has frequency response speci-
fications. It’s usually expressed in Hertz (or
cycles per second), like “40Hz–300Hz.” The
“40Hz” refers to the low-frequency point (usu-
ally, but not always) where the speaker’s
output drops by 3 dB, and will “roll off” com-
pletely as the frequency goes down. There is no
point in sending a woofer any frequencies it
can’t reproduce — you can’t hear it, and worse
yet, it’s a waste of amplifier power that can be
better used reproducing frequencies you can hear.
10 Hz 1 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15 dB
–10 dB
–5 dB
0
dB
5 dB
L C Fil
Lev
el, dB
Frequency, Hz
LOW CUT
FILTER
170 Hz OFF
100 Hz
STAGE
MONITOR
TYPICAL
35 Hz