Circle 5 & Circle 3 - Passive
Choosing an amplifier to match your speakers and
application is important. The passive HHB Circle 5 requires
connection to a power amplifier with a suggested output
between 50 and 200 Watts RMS, and the Circle 3 should be
powered by an amplifier with an output of 30 to 100 Watts.
Connection is made via a pair of binding posts on the rear of
the loudspeaker. Take care to ensure that the positive (red +)
terminal on the loudspeaker is connected to the positive
(red +) terminal on the amplifier, and that the negative
(black -) terminal on the speaker is connected to the
negative (black -) terminal on the amplifier. Connecting one
of the loudspeakers out of phase will result in dramatic loss
of low frequency signals and an incoherent spatial image.
Always use good quality medium or heavy-duty speaker
cable, not thin ‘bell’ wire. The main function of a speaker
cable is to transfer the maximum amount of current with the
minimum amount of distortion. It is therefore preferable to
have a cable with a wide cross-sectional area, since this will
reduce the electrical resistance. If the cable is too thin, the
resistance rises and heating may occur. Where possible, try
to use the same length of cable for each speaker.
Circle 5 & Circle 3 - Active
Audio connection to the active HHB Circle 5 and Circle 3 is
via balanced XLR or unbalanced RCA phono. The audio
should be connected to one or the other input, not both, with
the input switch being set accordingly. Note that in the active
Circle 5 this switch only balances and unbalances the inputs
and does not actually switch between the two. Signal should
never be connected to both inputs simultaneously, since the
output from the loudspeaker will be a combination of both
inputs. The active Circle 5 and 3 should be connected to a
suitable mains power supply via an IEC connector. Power
should be switched off when connecting or disconnecting
any signal to or from the loudspeakers, or when changing
the position of the selector switch, since the loudspeakers
and internal amplifiers may be damaged. When audio cable
runs are long - about ten metres or more (approximately
thirty feet) - or there is electromagnetic interference in the
vicinity of the cable (from a motor, for instance), it is
advisable to use balanced XLR cables so as to avoid any
induced noise. The master volume control on the active
Circle 5 and 3 acts as a sensitivity control. When at its
highest, the input is at maximum sensitivity and the
amplifiers will be fully driven by an input of 1V. The best way
to set this correctly is to ensure that the monitor output of
the mixing desk or other equipment that is driving the
speakers, is set to produce a peak output of 1V. The master
volume control also allows for balancing between
loudspeakers; ideal for use in a surround sound
environment.
Circle 1 Active Sub-Woofer
The HHB Circle 1 is an active sub-woofer, containing built-in
amplification and active crossover circuitry, designed
especially for use with Circle 5 and Circle 3 loudspeakers in a
surround sound setup. Its flexible input and output
capabilities allow quick and simple connection to the other
loudspeakers. The HHB Circle 1 sub-woofer has two distinct
modes of operation, set by a switch on the rear panel - these
modes are ‘5.1’ and ‘B’. The system is designed for decoded
or discreet 5.1 reproduction but also caters for earlier
formats of surround sound or bass enhancement in a
conventional stereo system. Using the HHB Circle 1 in ‘5.1
mode’ there are two connection methods in a surround
sound system. With method 1, the separate sub input allows
direct connection from a dedicated line level low frequency
effects (or sub) channel on a surround sound decoder,
mixing desk, or a multitrack recorder, Using this method,
only one physical connection is made to the
sub-woofer - the other five loudspeakers are sent their own
discrete signals directly from the mixing desk, etc.
Loudspeaker Connection
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