Installation And Operation; Important Notes On Safety; Operating Conditions; Speaker Placement - Klein + Hummel O 300 D Installation And Operation Manual

1. Installation and Operation

1.1 It is absolutely essential that you read
and observe the Safety Instructions on
page 2 before connecting or using this
device.

1.2 Operating conditions

The K+H model O 300 D active studio monitor
is intended for use over a range of ambient
temperatures from +10° C to +40° C (+50° F to
+104° F). During transport or storage,
temperatures from -25° C to +70° C (-13° F to
158° F) are permissible.

1.3 Speaker placement

The loudspeaker chassis used in the O 300 D
are magnetically shielded, so you are free to set
the speakers right next to a video monitor without
needing to worry about adversely affecting the
screen. Furthermore, the baffle of the O 300 D
is designed in such a way as to disperse the
sound very evenly not just on axis but over quite
a wide listening area. Any engineer who has sat
at a console for any length of time will appreciate
the considerable freedom of movement afforded
by the O 300 D. The cabinet is normally designed
to be used in the horizontal position, as the
vertical angle of dispersion has intentionally been
made narrower than the horizontal. The cabinets
are constructed in a left version and a right
version. For best stereo imaging and depth of
soundstage, position the cabinets with the
tweeters on the outside, at ear height, pointing
directly at the listening position. If you use the
O 300 D as a center speaker, set the cabinet
vertically, with the tweeter and midrange dome
at the top.
In certain applications where there are hard
reflective surfaces immediately to the left or right
of the speakers, it may make more sense to set
the cabinets vertically, in which case the
narrower dispersion pattern will help reduce
comb-filter effects.
When choosing a location for the speakers, be
aware that you can take advantage of the inte-
gral room-compensating equalizer, which will be
described in detail in section 1.7.5 .
The cabinet can be mounted directly to a wall or
ceiling with the aid of the LH 25 mounting
bracket. On the left and right sides of the cabinet
you will find threaded bushings of 8 mm diameter
to which this bracket attaches. As an alternati-
ve, you can use the LH 28 stand-mount adapter
Page 4
to set the speaker on a standard 35-mm
(1-3/8") tripod.
Please make certain that these two threaded
openings are always sealed, either with the
plastic plugs that come standard with the
cabinets or with the screws holding the mounting
adapter in place. Otherwise you may experience
some air noise and possibly some degradation
in low-frequency response.

1.4 MAINS Connection

The amplifier electronics of the standard
European model are set up for an AC line voltage
of 230 volts, 50 or 60 Hz. Export versions with
other voltages are also available. If the power
plug of the mains cable should ever need to be
replaced, ensure that the connection to the
protective earth is maintained.
1.5 MAINS Switch (POWER)
When you switch on power to the unit, there is a
five-second delay before the amplified signal is
sent to the drivers. This delay avoids the loud
popping sounds that otherwise may be
generated by devices earlier in the signal chain
as power reaches them. You will find this
arrangement particularly useful if your studio
uses a master switch to power up all the
equipment at once. When power on the O 300 D
is turned off, on the other hand, or if there is a
general power failure, the signal flow to the
speaker is immediately cut off, preventing any
loud pops.

1.6 Mains FUSE

When replacing the fuse, first disconnect the
mains cable and ensure that the new fuse is of
the following type only:
for 230 volts AC 1.6 A Slo-Blo (5 x 20 mm)
for 117 volts AC 3.15 A Slo-Blo (5 x 20 mm)
for 100 volts AC 4 A Slo-Blo (5 x 20 mm)
Active Studio Monitor O 300 D
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