EKAPPA 15A
Operating instructions
The EKAPPA15 is an active subwoofer, i.e. with an integrated amplifier. It serves to expand the LD
Systems speaker program. Strong support is provided for the LDE122 (A), LDPN122(A) and
LDPN152(A), which due to the reduced load in the bass range can attain a greater undistorted sound
pressure level.
In addition to being used with LD Systems speakers, the ASUB 15 can of course also be connected to
products of other manufacturers.
The EKAPPA15 transmits the bass in mono format. This is standard, and is due to the fact that the
human ear is unable to localise and determine the direction of bass frequencies.
Set-up
Due to the fact that low frequencies cannot be localised, the positioning of a subwoofer is not
particularly critical. It is not at all necessary to set it up exactly midway between the satellite speakers;
it is quite possible to position it to the side. On the top of the EKAPPA15 is an attachment for a
speaker stand for a corresponding satellite speaker. The positioning of the subwoofer to one side is to
be recommended only when it is to be used in a room of limited size, otherwise the listener will
experience too much discrepancy in the bass level to the left and right due to differences in distance.
Of course general safety rules for electronic equipment apply. For instance, the subwoofer must not
be subjected to sprayed water or to extreme heat. The air supply to the fan at the rear must not be
obstructed.
Connections
Connect the left/right outputs of the mixing console to the inputs of the EKAPPA15. These are the XLR
female connectors labelled INPUT. Since the inputs are balanced, it is necessary to use a balanced
cable (microphone cable). Above the input connectors are XLR male connectors labelled
OUTPUT/THRU, for throughput of the signal. These can be used to connect another subwoofer, for
example. In addition to these outputs there are two other outputs, the signal of which is filtered by a
crossover from the low bass frequencies transmitted by the subwoofer. The XLR female connectors
labelled HIGH PASS 120 Hz L/R transmit in stereo the signal supplied via the INPUT connectors.
Active speakers of the LD Systems series can be connected directly here, likewise using a balanced
cable. If you do not have active speakers, a suitable power amplifier must be connected here. It is not
necessary to connect a crossover since, as described above, division of the frequencies is carried out
in the subwoofer.
An IEC AC connector for the power cable, the power switch, and a ground lift switch, with the aid of
which ground loop hum is suppressed, complete the control elements on the back of the subwoofer.
After the subwoofer is switched on, the green POWER LED lights up. If a signal is already present at
the input, the LED labelled SIGNAL blinks or is lit up depending upon the strength of the signal. You
can use the LEVEL control to set the desired volume of the EKAPPA15. If the LED labelled LIMIT is
blinking, this indicates that maximum performance of the subwoofer has been reached and that the
integrated CLIP limiter is limiting the signal. In this case the LEVEL control should under no
circumstances be turned higher, causing the LIMIT indicator to be permanently lit up. However, a
rhythmic blinking, which indicates the limiting of signal peaks, is quite acceptable.
PROTECT indicator
If the protective circuits are activated in the event of failure, this is indicated by a special PROTECT
LED. For example, this could occur if the supply of fresh air for the fan is obstructed.
ATTENTION:
In the case of a serious operational disruption (which as a rule never occurs during normal
operation), in order to reset the protective circuit, the EKAPPA15
must be reset by turning the
power switch off and then on again.
Function of the PHASE switch
The switch labelled PHASE has two positions: NORMAL and REV180. When the switch is in the
NORMAL position, the signal from the EKAPPA15 is processed in phase with the input signal. When
the switch is in the REV180 position, the phase is shifted 180 degrees, which causes the signal to be
