Section 7 Operation
7 . 1
O p e r a t i n g L i m i t s
While the JF
NT
/KF
NT
processing includes robust driver and amplifier protection algorithms and
circuits, it is ultimately the responsibility of the audio system operator to operate the
loudspeakers within their capabilities. This is the only way to ensure that loudspeakers are not
stressed beyond their limits to the point of damage or failure.
Operation beyond their capabilities usually includes, but is not limited to, one or more of the
following conditions:
Severe amplifier clipping
Noticeable distortion
Mechanical noise (such as cones bottoming out)
The JF
NT
/KF
NT
has both Limiter Active and Clip indicators. A suitable means for determining if
these indicators are active is highly recommended. At a minimum, the operator should have a meter
display calibrated to indicate the level where the JF
NT
/KF
NT
s Limiting and Clipping point are and
thus be near to exceeding their capabilities.
As an alternative to a mixing console or other meter display, the EAWPilot provides real-time meter
display of the JF
NT
/KF
NT
levels.
7 . 2
A d j u s t i n g t h e O u t p u t L e v e l
With a source program playing, gradually turn up the level of your signal source until the desired volume is
reached or until the LIMITER ACTIVE light flashes only occasionally, whichever comes first.
7 . 3
O p e r a t i n g I n d i c a t o r s
For the instructions in this section, refer to the figures on pages 7 & 8.
7.3.1
LIMITER ACTIVE
The limiting parameters set in JF
NT
/KF
NT
s DSP are engineered to provide a high level of protection
for the drivers while maximizing sonic performance and output. The LIMITER ACTIVE indicator
in the rear input panel illuminates when limiting is occurring. If this is flashing occasionally,
meaning no more than once every 3 seconds or so, then levels are probably OK, but at maximum.
If this indicator is flashing more than once every 3 seconds or so, reduce the input signal level.
7.3.2 CLIP
The CLIP indicator on the rear panel illuminates if any of JF
NT
/KF
NT
electronics are being driven
into clipping. This includes the entire signal chain from the input stage through the DSP. Clipped
signals can more easily damage drivers as they can raise the average signal level significantly with
a spectrum that differs significantly from the input signal.
7.3.3 IMPORTANT: OPERATOR RESPONSE
If either or both of the LIMITER ACTIVE and CLIP indicators are flashing occasionally, meaning no
more than once every 3 seconds or so, then the signal level may not be excessive. However, this is a
CLEAR indication the loudspeaker is being operated near or at its maximum limits. If either or both
of these indicators are flashing more than once every 3 seconds or so, or are on steadily, reduce the
input signal level or damage to the drivers is likely to occur.
18
