Mackie TH-18S Manuale Utente

12

The TH-18s subwoofer is designed to sit on the 

floor or stage. It is not designed to be pole-mounted or 
suspended. 

When pole-mounting loudspeakers, be sure that the 

TH-18s subwoofers are stabilized and secured from  
falling over or being accidentally pushed over. For 
stacked scenarios, it is highly suggested that straps are 
utilized. Failure to follow these precautions may result 
in damage to the equipment, personal injury, or death. 

WARNING: The cabinet has no rigging 
points and is not suitable for rigging.  
NEVER attempt to suspend the TH-18s by 
its handles. 

As with any powered components, protect them from 

moisture and extreme cold and follow the other Care 
and Maintenance suggestions below.

Your Mackie subwoofers will provide many years of 

reliable service if you follow these guidelines:

•  Avoid exposing the subwoofers to moisture. If

they are set up outdoors, be sure they are under 
cover if rain is expected.

•  Avoid exposure to extreme cold (below

freezing temperatures). If you must operate 
the subwoofers in a cold environment, warm 
up the voice coils slowly by sending a low-level 
signal through them for about 15 minutes prior 
to high-power operation.

•  Use a dry cloth to clean the cabinets. Only do

this when the power is turned off. Avoid getting 
moisture into any of the openings of the cabi-
net, particularly where the driver is located.

There are several protection mechanisms designed 

into the TH-18s to safeguard the subwoofers and 
amplifiers from inadvertent damage. 

CAUTION: The protection circuits are 
designed to protect the subwoofers under 
reasonable and sensible conditions. Should 
you choose to ignore the warning signs (i.e., 

frequent OL LED indications, excessive distortion), you 
can still damage the speakers in the TH-18s by overdriving 
them past the point of amplifier clipping. Such damage is 
beyond the scope of the warranty.

The driver has its own compression circuit, which 

helps protect it from damaging transient peaks. The 
compressor is designed to be transparent and is not 
noticeable under normal operating conditions.

A 12 dB/octave high-pass filter at 40 Hz just prior 

to the low-frequency amplifier prevents very low 
frequencies from being amplified. Excessive low-
frequency energy below 40 Hz can damage the woofer by 
causing it to “bottom out,” also known as overexcursion, 
which is equivalent to a mechanical form of clipping.

All amplifiers produce heat. The TH-18s is designed 

to be efficient both electrically and thermally. 

The amplifier module is mounted on a large 

heatsink, which is cooled by convection where cool air 
is drawn over the rear panel, carrying the heat away. 
In order for this convection cooling to work efficiently, 
it is important to provide adequate airspace behind 
the subwoofer. When you position the TH-18s, we 
recommend leaving at least six inches of air space 
behind it.

 

  If for some reason the internal temperature gets too 
hot, a built-in thermal switch activates and turns down 
the amplifier. When the amplifier cools down to a safe  
temperature, the thermal switch resets and normal 
operation resumes. If the internal temperature again 
gets too hot, the output level reduction process repeats. 
Should this happen, make sure that airflow to the rear 
of the cabinet is not restricted.