User Manual

5
Minimise Reflections
Acoustic reflections from objects close to the monitors like desks,
cabinets, computer monitors etc. can cause unwanted coloura-
tion and blurring of the sound image. These can be minimised by
placing the monitor clear of reflective surfaces. For instance, put-
ting the monitors on stands behind and above the mixing console
usually gives a better result than placing them on the meter bridge.
Symmetrical positioning of the reflective objects is also important
in order to maintain a balanced soundstage (See Figure 4).
Low Frequency Cancellations
In general, when a monitor’s front baffle is more than 0.3 meters
(1 foot) away from the wall behind the monitor, a reflection from
this wall can cause a cancellation of low frequencies and hence
reduction of bass output. Distances between 1 and 2.2 meters
(3-7 ft.) should be avoided (See Figure 5).
As a rule of thumb, the lower the low frequency cut-off the further
away the monitor must be placed from the wall in order to avoid
this phenomenon.
Distances to the ceiling and other walls may be shorter than the
distance to the wall behind a monitor. Reflections from these sur-
faces may be important and should also be considered
Operating Environment
These monitors are designed for indoor use only. The permissa-
ble ambient temperature is 15-35 degrees Celsius (50-95°F) and
permissable relative humidity between 20% and 80%. Humid-
ity condensation on the product is not allowed during use. If the
product has been stored or transported in a cool environment
and then taken into a warm room, it must be allowed to warm up
completely before connecting to mains power.
Sufficient cooling for the amplifier and functioning of the reflex
port must be ensured if the monitor is installed in a restricted
space such as a cabinet, or integrated into a wall structure. The
surroundings of the monitor must always be open to the listening
room with a minimum clearance of 5 centimeters (2”) behind,
above and on both sides of the monitor. The space adjacent to
the monitor must either be ventilated or sufficiently large to dis-
sipate heat so that the ambient temperature does not rise above
35 degrees Celsius (95°F).
Mounting Options
The vibration insulating Isolation Positioner/Decoupler™ (Iso-
Pod™) table stand allows tilting of the monitor for correct align-
ment of the acoustic axis. The stand can be attached to three
mounting points allowing vertical and symmetrical horizontal
positioning.
Genelec 8240A, 8250A, 8351A and 8260A can be fitted to König
& Meyer monitor mounts on two sets of M6x10 mm threaded
holes on the back of the enclosure. On the base of the 8240A
and 8250A enclosure is an M10x10 mm threaded hole which
Figure 7. System Level rotary control
Figure 8. Switch Group 1
can be used for securing the monitor to its base. Do not use this
thread for mounting the monitor on a microphone stand which
has a 3/8” UNC thread. A wide variety of ceiling and wall mounts
are available through your Genelec dealer.
Setting the Input Sensitivity
The monitor level sensitivity functions for both analog and digital
input. The sensitivity can be matched by adjusting the rotary Lev-
el control together with the System Level switches located in the
switch group 2. (switches 6 and 7). The switches provide attenua-
tion levels of -10 dB (sw. 6 ON), -20 dB (sw. 7 ON) and -30 dB (both
switches ON) The combined attenuation ranges from 0 to -42 dB.
Functions On Switch Group 1
(Tone Controls)
Switch group 1 (the upper switch group) comprises the tone
controls that can adjust the frequency response of the system in
stand-alone mode to match the acoustic environment.
Please note that the GLM software allows a much more versatile
and precise set of controls to be used and supports the fully
automatic system alignment feature, the Genelec AutoCal. Use
the tone control switches on the monitor only if GLM is not avail-
able for the system calibration.
The controls are labelled “TREBLE TILT”, “BASS TILT”, “BASS
ROLL-OFF” and “DESKTOP”. The factory settings for these con-
trols are all “OFF” to give a flat anechoic response. Note that these
controls have no effect when switch 1 “STORED/MANUAL CON-
TROL” on switch group 2 is set to “STORED” or when the monitor
is connected to the Genelec monitor control network.
The use of an acoustic measurement system is recommended to
analyze the effects of the adjustments, however, careful listening
with suitable test recordings can also lead to good results if a test
system is not available. Start adjustment by setting all switches