Quested SB10 User Manual - page 9
9
5.8
Polarity
This controls the polarity of the sub bass. It is used in conjunction with the phase control to
accurately
match the sub bass with both the full range monitors and the environment they
are being used in. Two green LED’s indicate when the sub bass polarity is both positive and
negative.
5.9 Power
On and off.
5.10 Rear Panel Controls
Left input filter bypass
A recessed switch on the rear panel allows the left input filters to be bypassed changing the
left input to full range. A full range input should be used for a LFE source that has been
externally filtered. This switch should be used with caution. The SB10 should never be used
without any low pass filters. To use the SB10 without any low pass filters is likely to cause
damage to the drive unit. This is because the cabinet has a large resonance that is out of
the normal operating bandwidth.
5.11 Internal Settings
Sub sonic/High pass filter
It is possible to change the subsonic/high pass filter from 14-28 Hz with internal jumpers.
There should be no need to alter this, as the unit will be shipped configured correctly for use
with your unit. This filter is used to gain more amplifier headroom if the speakers operating
bandwidth is above 28 HZ. IF this setting is to be changed, firstly disconnect all power and
signal leads. Remove the cover of the SB controller using a Torx driver. Locate the 4 jumpers
that are clearly marked and located on the main PCB behind the gain and phase pots. To fit
all of the jumpers will set the high pass filter to 28 Hz and to remove them all will set it to
14
Hz.
6 SETTING UP: THE WHYS AND HO WS O F SUBW O OFER USE
6.1
WHY?
The SB10(s) can be incorporated into a compact stereo monitor system to either extend
the system low frequency response, or increase the maximum system SPL, or to achieve
combination of both. Additionally SB10s can be utilised to reproduce the L.F.E.
or .1
element
of a multi-channel system. In order to meet these objectives it is important that some
thought
is given to the positioning of the SB10(s) and that care is taken with the adjustment of the
crossover frequency, phase and relative levels.
The performance of any loudspeaker in a typical room will be, to an extent, dependant upon
its position. This is particularly true of subwoofers as low frequencies are more susceptible to
changes of cabinet position than high ones. There is a common misconception that bass is
not directional, the truth is that as the frequency lowers the less directional it becomes. For
this reason the higher the low pass frequency of the subwoofer the more critical its position
relative to the rest of the monitor system. If part of a program being played has transient
low
frequency components e.g. a kick drum, bad positioning of the SB10 will be particularly
evident.
6.2
HO W?
Positioning: Typical examples of stereo installations with a pair of S6 near-field monitors
and
a single SB10 are illustrated in Figs 1 & 2. The nearfield monitors are 120 cm from the
listening position and the SB10s are sited between the left and right monitors. Ideal
placements would be as in Fig. 1 for symmetrical room layouts and as in Fig. 2 for
asymmetric room layouts. In both examples the SB10s are on the same radius as the
left and right monitors and the centre of the arc is the listening position. To obtain the most