Owner’
s Manual
11
Owner’s Manual
Thump18S Subwoofer: Rear Panel Features continued...
7. Level Knob / OL LED
The level knob adjusts the input sensitivity of the
inputs. This allows signals from the outside world to
be adjusted to run through each channel at optimal
internal operating levels. There is –6 dB of gain with the
knob fully down (off), ramping up to 6 dB of gain fully
up (max). The level control has no effect on the high
pass outputs or full range outputs.
The accompanying OL (overload) indicator
illuminates red when the amplifier in the Thump18S
is near the clipping point. It is OK if the OL LED blinks
occasionally, because this means that the transient
peaks are just reaching the maximum output of
the amplifier and you are getting the most out of
the subwoofer.
However, if the OL LED is blinking frequently
or continuously, turn down the level control on
the Thump18S or turn down the signal at its source
(e.g., the mixing console) until the OL LED blinks
occasionally or not at all.
8. Normal/Invert Switch [Polarity]
This switch reverses the polarity of the signal going
into the subwoofer amplifier by 180˚. It has no effect on
the signal at the outputs.
There is no right or wrong setting for this switch.
Listen to the overall blend of the subwoofer with
the rest of the system and select the switch position
that gives you the best sound for your audience.
In fact, your system may vary when positioned
differently and in alternate venues. Don’t be afraid
to experiment with the position of the polarity switch.
See page 12 for more information.
Questionnaire
There is quite a bit of blank space left over, so why not
fill it with a questionnaire?
• Beatles or Stones?
• Star Wars or Star Trek?
• Chocolate or vanilla?
• Batman or Superman?
• Dogs or cats?
• Beer or whiskey?
• Pizza or cheeseburger?
• Football or baseball?
• Playstation or Xbox?
• Jimmy Page or Jimi Hendrix?
• Family Guy or South Park?
• Coffee or tea?
• What is your favorite color?
• What is the air-speed velocity of an unladen
swallow?
Final Thoughts
The following pages discuss Thump18S placement, an
in-depth look at polarity, protection circuitry, technical
information and much more. Check it out!
