Front Panel Description; Power Switch; Power Ring And Overload Indicator; Protection Circuits - Mackie HR824 MK2 Owner's Manual

FRONT PANEL DESCRIPTION

9. Power Switch

Use this switch to turn on or off the HR824 MK2 from
–
10dB
the front. It works with the POWER MODE [6] switch
on the rear panel in the following way:
• If the POWER MODE switch on the rear panel is set
OFF NORMAL
to STANDBY, the front panel power [9] switch has no
QUARTER HALF
INPUT
effect. The power [10] ring remains off.
SENSITIVITY ACOUSTIC SPACE
• If the POWER MODE switch is ON, the front panel
power switch turns the HR824 MK2 on or returns it to
STANDBY mode, as indicated by the power ring.
• If the POWER MODE switch is in the AUTO ON posi-
tion, the front panel power switch turns the HR824 MK2
on, even when there is no signal present. If there is no
signal after about two minutes, the auto-off function
is activated and the amplifiers go into Standby mode,
indicated when the power ring goes off.

10. Power Ring and Overload Indicator

The power ring around the power switch illuminates
when the power amplifiers are on, and turns off when
the amplifiers are in Standby mode or off.
The power ring turns red when the overload protec-
tion circuit has been triggered.
• Occasional blinking of the overload indicator means
that the loudest transients are reaching the maximum
drive capability of the amplifiers. This is okay, although
distortion may be audible.
• Frequent or continuous blinking of the overload indica-
tor means that you have exceeded the maximum drive
allowed for the speakers. The amplifiers are clipping,
and the overload protection circuit has taken over, re-
ducing the input level. You should reduce the level from
your signal source until the overload indicator blinks
occasionally or not at all.

PROTECTION CIRCUITS

There are a number of protection mechanisms de-
signed into the HR824 MK2 to safeguard the loudspeak-
ers from inadvertent damage.
CAUTION: The protection circuits are designed to
prevent damage to the loudspeakers under reasonable
and sensible conditions. Should you choose to ignore
the warning signs (i.e., frequent overload indications,
excessive distortion), you can still damage the speakers
in the HR824 MK2 by overdriving them. Such damage is
beyond the scope of the warranty.
1
HR84 MK
80Hz 47Hz 37Hz
( NORMAL )
LOW CUT
WHOLE
( NORMAL )
LOW FREQ
–
2dB 0 2dB STANDBY
+
( NORMAL )
AUTO
ON
HIGH FREQ. POWER MODE

Overload Protect

• If you see the overload indicator [10] blinking more
than just occasionally, it's an indication that you should
reduce the signal level coming from your mixer or other
signal source.
• The blinking overload indicator means the driver
thermal overload protection has activated a compressor.
This reduces the input level to the amplifiers.
• The compressor was designed to protect the speakers
and its action is highly audible.
are the low frequencies, selectively reducing the low
end can provide a little more headroom and volume
for the monitors. Change the LOW FREQ FILTER [4]
switch to 80Hz if necessary, to reduce the bass response.
This may allow the HR824 MK2s to play just enough
louder to satisfy the client and to eliminate most of the
amplifier clipping.
ON
If a client insists on listening to the
monitors at a very high volume, you
may find that the overload indicator
lights frequently. Since the majority of
the power requirement in any monitor