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Loudspeaker mounting
Bass
position
roll-off
Free anechoic response
None
Free standing in a
None
damped room
Free standing in a
None
reverberant room
In a corner
-2 dB
Flush mounted
None
Table 1. Suggested tone control settings for different acoustic environments
W1
H1
H1 mm (in)
W1 mm (in)
HT312A
540 (21
1
/
")
200 (7
4
HT315A
650 (25
5
/
")
240 (9
8
Figure 1. Location of the acoustic axis
10kOhm balanced XLR connector, but unbal-
anced leads may be used as long as pin 3 is
grounded to pin 1 of the XLR. Once connec-
tion has been made, the loudspeakers are
ready to be powered-up.
Setting the input sensitivity
Adjustment of the input sensitivity of each
loudspeaker can be made to match the output
of the mixing console or other source, by use
of the input sensitivity control on the rear
panel (see Figure 2). A small screwdriver is
needed for the adjustment. The manufacturer
default setting for this control is -6 dBu (fully
clockwise) which gives an SPL of 100 dB
@1m with -6 dBu input level. To get the full
output level of 120 dB SPL from the HT315A
an input level of +14 dBu is needed at this
setting. Respectively, the full output level of
the HT312A is reached at an input level of
+10 dBu.
Autostart and remote control
The HT312A and HT315A are equipped with
an "Autostart" function, which automatically
turns the amplifier to "standby" mode if an
input signal has not been detected for approx-
imately thirty minutes, and back to "on" mode
when the signal returns. The function can be
deactivated by turning the "AUTOSTART" dip
switch to "OFF". A two-colour LED on the
amplifier panel indicates the amplifier status:
Bass
Bass
Midrange
Treble
tilt
level
level
level
None
None
None
None
-2 dB
None
None
None
-2 dB
-2 dB
None
None
-2 dB
-2 dB
None
None
None
-4 dB
None
None
H2
W2
ACOUSTICAL
AXIS
H2 mm (in)
W2 mm (in)
7
/
")
230 (9
1
/
")
170 (6
11
/
")
8
16
16
1
/
")
282 (11
1
/
")
202 (7
15
/
")
2
8
16
green for "on" and yellow for "standby".
The amplifier mode can also be switched
by a remote control unit connected to the
respective inputs on the amplifier. Two pairs
of connectors are provided, 1 and 2 for a 12
V DC type remote control, and 3 and 4 for
an external switch or relay type control. Do
not connect two remote controls to the loud-
speakerat the same time. Activate the func-
tion by turning the "REMOTE CONTROL" dip
switch on the amplifier panel to "ON". Note
that the remote control function overrides the
"autostart" dip switch function.
Setting the tone controls
The acoustic response of the system may
also have to be adjusted to match the acoustic
environment. The adjustment is done by set-
ting the five tone control switch groups 'bass
tilt', 'bass roll-off', 'bass level', 'mid level' and
'treble level' on the rear panel of the amplifier.
The manufacturer's default settings for these
controls are 'All Off' to give a flat anechoic
response. See Table 1 for suggested tone
control settings in differing acoustic environ-
ments. Figures 7 and 8 show the effect of the
controls on the anechoic response. Always
start adjustment by setting all switches to
the 'OFF' position. Then set only one switch
per group to the 'ON' position to select the
response curve required. If more than one
switch is set to 'ON' (within one switch group)
Figure 2. Amplifier panel layout of the HT312A.
the attenuation value is no longer accurate.
Vertical / horizontal mounting
The loudspeakers are delivered either for
vertical or horizontal mounting. In the hori-
zontal mounting position the bass drivers
should point inwards to obtain better low
frequency coupling. If the loudspeaker posi-
tioning needs to be changed, the DCW plate
can be rotated so that the midrange driver
remains always located at the bottom of the
DCW. Remove the four corner screws of the
DCW and pull the plate carefully out without
stressing the wires and the gasket. Rotate
the plate 90 degrees in the appropriate direc-
tion and remount the screws.
The HT312A and HT315A can be used flush
mounted into the wall structure, which offers
some acoustical benefits. No cabinet edge
diffraction will occur, resulting in an improved
response, especially at midrange frequen-
cies. Low frequency reflections from the wall
behind the loudspeaker can be avoided,
which improves the low frequency response
and efficiency and allows the loudspeaker
to work in half space conditions. In terms of
installation and orientation, the loudspeaker's
acoustical axis (See Figure 1.) should also
point directly to the the reference listening
position. The loudspeakers should be verti-
Flush mounting
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