Gemini II User manual

Gemini II
OWNERS MANUAL
Subwoofer System
OWNERS MANUAL
Subwoofer System

CONTENTS
1) Safety instructions.
2)
3)
4)
5) Setting up your Gemini II.
6) Controls and their functions.
Connecting up your Gemini II.
Connecting up using the high level input.
Connecting up using the low level input.
7) Specifications.
Page No.

SAFETY INSTRUCTIONS
Caution:
To avoid the risk of electric shock do not remove the panel from the
cabinet. If this unit fails or has a serious deterioration in performance
then refer repair to the dealer where you purchased the unit.
1)Please read these instructions carefully and keep them for future reference.
2) Please heed all warnings.
3) Please follow these instructions.
4) Do not use this apparatus near water or allow to get wet.
5) Keep well ventilated.
6) Do not install near heat sources such as radiators, stoves etc.
7) Protect the power cord from damage.
8) Disconnect from the power supply during lightning storms or extended periods of
inactivity.
9) Refer all servicing to qualified service personnel. If the unit develops a fault of any
sort please refer repair back to your dealer.
10) Do not force the controls or switches further than their normal stops.
11) Clean with a dry soft cloth. If you do use polish, then apply polish to cloth not
directly to the unit.
(1)

To make connecting up of the Gemini II as versatile as possible we have included two
separate inputs. One Neutrik Speakon socket and one pairs of gold plated RCA sockets.
This is to facilitate use with both Hi-Fi and AV surround systems.
The high level input, is an unbalanced dual channel (stereo) input that uses a professional
touch proof Neutrik Speakon connector. Signals for this input would normally be sourced
from the left and right speaker terminals of the main system amplifier. The advantage of
this method is that the Gemini II receives exactly the same signal as being supplied to the
main speakers. This means that the character and tonal balance of the bass from the main
speakers is carried through to the sub bass.
The low level input is via one set of the gold plated RCA to RCA connectors marked as “IN”
on the front panel. Signals for the low level input are unbalanced and would normally be
sourced from the LFE output of an AC3 decoder. Alternatively the low level input can be
connected to a dedicated sub out of a processor (for single outputs connect to the input
marked “Mono”), or to stereo pre-amp output where available.
The Gemini II comes fitted with four black M8 nylon screws that act as feet and help prevent
the base of the subwoofer from getting scratched. If you wish to take advantage of the
isolating spikes that come supplied with the Gemini II then please follow the following
fitting instructions:-
First thread one nut per spike on each spike. Now remove the M6 nylon screws from the
bottom of the subwoofer and fit the four spikes. The cabinet can now be leveled by
screwing in or out each spike accordingly. When leveled tighten up each lock nut against
the base of the cabinet.
Caution: Take special care with the spikes as they are very sharp. DO NOT use on
delicate floor finishes
CONNECTING UP YOUR GEMINI
Always switch off your system before disconnecting or connecting any wires.
(2)

Figure 1. Shows a diagram on how to connect the high level input. Using the optional
Neutik lead, connect the Gemini II to the output of your amplifier via your existing speaker
plug or to a spare set of speaker terminals if available. In effect you are Bi-Wiring your
Gemini II to your power amp. Please note that the Neutrik cable has only three leads and is
arranged this way to preserve the star earthing of your amplifier (assuming it has a star
earth arrangement).
To connect the high level lead you will need to connect the RED wire to the RED terminal of
the RIGHT hand speaker terminal of your power amp. Connect the WHITE wire to the Red
terminal of the LEFT hand channel speaker terminal of your power amp. The BLACK wire
is connected to either one of the BLACK speaker terminals of your power amplifier. This is
important as some power amplifiers do not like their black terminals joined. Now plug the
neutrik connector into the high level input of the Gemini II. The Neutrik plug will fit only one
way as it has a key. Next push the plug in then turn clockwise until you feel it latch. To undo
the Neutrik plug, pull back the silver lever on the Neutrik plug and turn counter-clockwise.
Please Note: It may not be possible or advisable to connect the high level input directly to
an amplifier that has a class d digital output. Please check with the supplier of your
amplifier that this form of connection is possible.
If you do have a class d amplifier and are unable to use the high level input, then BK have
developed a sonicaly transparent isolator that overcomes this problem. Please contact us
for further details.
(3)
CONNECTING UP USING THE HIGH LEVEL INPUT
Figure 1.
BlackRed BlackRed
RIGHTLEFT
RedBlack
Method 1 - To Connect to a Power Amplifier Using the High Level Input
Neutrik Speakon Interconnect
HIGH LEVEL
INPUT
White

LEFT RIGHT
(MONO)
LOW LEVEL
INPUT
CONNECTING UP USING THE LOW LEVEL INPUT
Figure 2. Shows a diagram on how to connect the low level input. Using the supplied RCA
to RCA interconnect, plug one end into the Gemini II low level input and the other end into
the dedicated sub output on your amplifier or processor. If a sub out is not available then
you can use a spare set of pre-amp outputs.
If you only have a single sub woofer output socket on your equipment, then connect up
using one of the pairs of leads (red to red). In this instance use the (Mono) input on your
Gemini II sub.
Please Note that high and low level connections can be used at the same time if required.
This has the advantage of being able to connect up a Hi-Fi and AV system simultaneously.
(4)
LOW LEVEL
GAIN
INTEGRATED AMP / PRE-OUT
LFE / Sub Out
PROCESSOR
LEFT
RIGHT
Figure 2.
Method 2 - To Connect to the Amplifier Using the low level input

SETTING UP YOUR Gemini II
!Connect your Gemini II as shown in Figure 1 or Figure 2. Then attach your
subwoofer to the power supply using the power cable supplied, at this point have the
power switch in the off position.
!Now turn both the high level and low level gains to the minimum position, and the
frequency control to 120Hz. If using the subwoofer out from an AV Processor then
you may select the LFE position .Turn the phase control to position 1.
!Now switch the power on, and play a track which you are familiar with that has bass
content (If you are using both inputs then start by setting the high level input first
using an audio CD then repeat the setting up procedure on the low level input using a
film track).
!Adjust the gain control until the level of the bass from your subwoofer matches the
level from your main system speakers. Now slowly adjust the frequency control
counter clockwise until the output from the subwoofer meets the lowest notes from
your main speakers (the crossover point), you may need to adjust the gain control
again to match your main system speakers.
!The Gemini II has a fully adjustable phase control to allow partial cancellation of the
frequencies around the crossover point between the two systems. Listen to the
quality of the bass with the phase in the 0 deg position and then slowly adjust towards
the 180 deg position. Choose the position that subjectively offers the tightest
cleanest bass.
Following these setup instructions will get you up and running, but over a few days with
practice and a lot of listening you will be able to fine tune the system for seamless
integration.
As a rule it is not usually necessary to have the subwoofer at high volume levels, but to
have it gently supporting the main speakers.
(5)
Your Gemini II subwoofer has the unique ability to be connected to both a Hi-Fi and AV
Processor simultaneously. Allowing you to control both the frequency and gain of each
input independently of each other, two sub bass engines in one amp!

CONTROLS AND THEIR FUNCTIONS
(6)
8)Low
9)Low
Level Gain Adjust
Level Frequency Contour, set up so
as to integrate with main loudspeakers. In
the L.F.E. Position the filter is opened wide
to allow the optimum performance from
processor built in bass filtering.
10)Continuously Variable Phase Control
11)Power Off/On Switch
12)IEC mains input connector. (Fuse
Drawer contains spare 1.6AT fuse)
LEFT RIGHT
HI LEVEL INPUT
LOW LEVEL INPUT
(Mono)
PHASE
0180
00
HI LEVEL
GAIN
Min Max
LO LEVEL
GAIN
Min Max
30Hz 120Hz 30Hz 120Hz
HI LEVEL
FREQ
LO LEVEL
FREQ
(LFE)
30 60 90
100
150
WATTS
RMS
TO AVOID RISK OF ELECTRIC SHOCK DO NOT REMOVE
PANEL NO USER SERVICEABLE PARTS INSIDE. REFER
TO QUALIFIED SERVICE PERSONNEL.
230V
50-60Hz
T1.6 AL
POWER INLET
POWER
30 LFE
2
1
678910
35
11
12
4
1) High Level Input connector for
connection to amplifier output
2) Low Level Input RCA connectors for
connection to pre-amp output, Dolby
output or other dedicated sub outputs.
3)High Level Upper Roll Off Frequency.
4)Power Output Meter.
5)Low Level Upper Roll Off Frequency.
6)High Level Gain Adjust
7)High Level Frequency Contour, set up so
as to integrate with main loudspeakers.
Designed and manufactured by :-
www.bkelec.com
[phone]
B.K. Electronics
Southend-On-Sea
Essex. England
Gemini II 150W
Sub Bass System

(7)
SPECIFICATION
System Type:
Drive Units:
Amplifier:
Inputs:
Nominal impedance/input voltage:
Sensitivity/Features:
Dimensions HxWxD:
Weight each unpacked:
Infinite Baffle Sub-bass system with on-board amplification and active
filtering. Fully optimized enclosure manufactured from critically damped
18mm and 25mm MDF
250mm 10“ high-efficiency unit. Long stroke polypropylene cone
driver
150W RMS DC coupled bi-polar.
High Level 100K ohm unbalanced via Neutrik Speakon connector
Low level 10K unbalanced via gold plated RCA connectors.
110/120v (220/240v) where applicable.
Phase control 0 and 180 Deg.
High and low level mixing capability.
Automatic Speaker Protection
Dual Display’s
Power Metering
Gemini II 315D x 355H x 290W mm
13.4kg (29.48 lbs)
This product is subject to Directive 2002/96/EC of the European Parliament and the Council of the European
Union on Waste of Electrical and Electronic Equipment (WEEE) and, in jurisdictions adopting that Directive, is
marked as being put on the market after August 13, 2005, and should not be disposed of as unsorted
municipal/public waste. Please utilise your local WEEE collection facilities in the disposition and otherwise
observe all applicable requirements.
WEEE Consumer Notice