General description
Genelec HTS3 and HTS4 are powerful low
frequency loudspeakers designed specially
for high quality digital 5.1 channel Home
Theater systems. Both models share the
same design layout with one active, mag-
netically shielded speaker driver on the long
side of a compact rectangular cabinet and
two passive radiators, one at each end of
the cabinet. HTS3 and HTS4 are equipped
with ampliers rated at 200 and 400 Watts
respectively. The amplier unit is integrated
in the subwoofer cabinet.
XLR and RCA line level input connectors and
adjustable input sensitivity provide easy con-
nection to all types of decoders. Bass roll-off
rate and crossover phase can be adjusted
to suit different acoustical environments and
subwoofer positioning. A “LINK OUT” con-
nector allows coupling two or more subwoof-
ers together when high sound pressure levels
are required. The ampliers are equipped
with an “AUTOSTART” function for auto-
matic switching between “STANDBY” and
“ON” modes. Connectors for remote power
“ON/STANDBY” switches are also provided.
Installation
Each subwoofer is supplied with a mains
cable and an operating manual. Once
unpacked, place the subwoofer in a suitable
location (for more details see the ‘Positioning’
section).
Before connecting the audio signals, ensure
that both the subwoofer and the main mon-
itors are switched off. Check that the sub-
woofer voltage selector switch is set to the
correct voltage. Audio input to the subwoofer
can be made via balanced XLR (LFE IN 1)
or unbalanced RCA (LFE IN 2) connector. We
recommend the use of balanced cables and
connectors due to their better noise immunity.
Do not use both inputs at the same time.
The “LINK OUT” connector can be used for
daisy-chaining several subwoofers together
when high SPL is required. Simply connect
a balanced XLR cable from the “LINK OUT”
connector to the “LFE IN 1” connector of the
next subwoofer. See section “Using multiple
subwoofers”.
Once all connections have been made, the
subwoofer and main monitors are ready to be
powered up.
Positioning in the room
The placement of the subwoofer in the room
affects the overall frequency response and
sound level of the system dramatically, as in
low frequencies the effects of the room are
strong. Even a slight change in the subwoof-
er’s location can make a marked difference
in the frequency balance and often a patient
and methodical experimentation and testing
is needed to nd the optimum placement.
The placement will affect the phase differ-
ence between the main monitors and the
subwoofer, and also the bass roll-off rate.
These effects can be compensated by the
use of the controls in the amplier unit; but
we recommend that at rst you leave the
switches untouched and concentrate on nd-
ing the position where the subwoofer gives
the smoothest response, and only then use
the controls to ne-tune the balance and
phase alignment between the subwoofer and
the main monitors.
To begin with, place the subwoofer close to
the center of the front wall, however leaving
at least 10 cm (4”) of free space before the
amplier, driver and passive radiators. We
recommend a distance of less than 90 cm /
36”. This position gives increased acoustic
loading (and SPL) due to the proximity of the
front wall and oor. Cancellations from the
front wall and oor are also avoided. Front
wall cancellation for the high pass ltered
main speakers can be eliminated by placing
them at least 110 cm / 43” away from the
front wall. In a multichannel system the sub-
woofer and main monitors should ideally be
positioned symmetrically and at an equal dis-
tance from the listening position.
If the frequency balance is not quite right, try
moving the subwoofer slightly to the left or
right so that different room modes are excited
at different levels. Positioning the subwoofer
close to a corner will boost the bass level
at lower frequencies and may cause asym-
metrical spatial imaging. If you are using two
subwoofers, try placing them asymmetrically
relative to the side walls. Sometimes moving
the subwoofers apart into the front corners
helps with problematic rear wall reections
and the loss of mutual coupling is compen-
sated by the bass boost caused by corner
positioning.
Although the HTS3 and 4 are magnetically
shielded, they may cause colour distortion if
placed near to very sensitive video monitors
or computer displays. Move the subwoofer
further away or try turning the amplier side
of the subwoofer towards the screen.
Soft / Cabinet mounting
If the subwoofer is installed in a cabinet or
ush mounted in a cavity inside a wall, suf-
cient space must be left around it to ensure
amplier cooling and correct functioning of
the driver/passive radiator system.
The cavity must be at least 20 cm (8”) wider,
10 cm (4”) deeper and higher than the outer
dimensions of the subwoofer. This allows
leaving 10 cm (4”) of space around all sides
of the cabinet. The subwoofer’s amplier side
must face the back of the cavity and the
driver on the opposite long side of the cab-
inet into the room. If the cavity is covered
with a drape or cloth, ensure that it does
not hinder the air circulation around the sub-
woofer.
Setting the input sensitivity
The subwoofer requires input sensitivity align-
ment to the source to obtain a correctly bal-
anced system. The input sensitivity control
is located on the amplier panel of the sub-
woofer. An input voltage of -6dBu with a
-6dBu input sensitivity setting will produce
100dB SPL @ 1m in free eld. To obtain
a 110dB SPL output an input voltage of
+10dBu is required when the input sensitivity
is set to 0dBu.
Setting the bass roll-off switches
The acoustic response of the subwoofer may
have to be matched to the characteristics of Figure 1. Connectors and controls of the HTS3 and HTS4