Speaker Placement; Operation; Front Panel Controls - Gemini SP-1 Service Manual

Circle surround processor
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Connections
1. Before plugging in the power cord, make sure that the VOLTAGE
SELECTOR (9) switch is set to the correct voltage.
2. Make sure that the POWER (10) switch is in the off position. The
POWER LED (11) will be off. All connections must be made with all
equipment OFF.
3. On the rear panel is one set of electronically balanced stereo INPUTS
(7, 8). The INPUTS (7, 8) are used to connect to the output of your
mixer using standard XLR cables. The balanced inputs have three
separate conductors, two of which are signal (positive and negative)
and one which is a shield (ground). Pin 1 is ground (shield). Pin 2 is
signal hot (positive). Pin 3 is signal cold (negative).
4. The SP-1 is supplied with 5 BALANCED OUTPUTS (1, 2, 3, 5, 6). The
BALANCED OUTPUT connectors are used to connect to your
amplifiers using standard XLR cables. Connect the BALANCED
OUTPUT (1) to the amplifier for the subwoofer. Connect the
BALANCED OUTPUT (2) to the amplifier for the rear right speaker.
Connect the BALANCED OUTPUT (3) the amplifier for the rear left
speaker. Connect the BALANCED OUTPUT (5) to the amplifier for the
front right speaker. Connect the BALANCED OUTPUT (6) to the
amplifier for the front left speaker. The BALANCED OUTPUTS have
three separate conductors, two of which are signal (positive and
negative) and one which is a shield (ground). Pin 1 is ground (shield).
Pin 2 is signal hot (positive). Pin 3 is signal cold (negative).

Speaker Placement

Just like in a theater or a home surround system set up, speaker
placement should be arranged to create a box in order to maximize the
effect of the SP-1. Refer to Page 2 for greater detail. Position the
subwoofer between the front speakers. If you position the subwoofer in
front of a wall or facing away from a corner, you will gain subwoofer output.
Using the Ground Lift Switch
Depending on your system configuration, sometimes applying the ground
will create a quieter signal path. Sometimes lifting the ground can
eliminate ground loops and hum to create a quieter signal path.
1. With the unit on, listen to the system in idle mode (no signal present)
with the ground applied (the GROUND LIFT SWITCH (4) in the left
position).
2. Then turn the power off before moving the GROUND LIFT SWITCH
(4). Lift the ground by moving the GROUND LIFT SWITCH to the right,
turn the power back on and listen to determine which position will
provide a signal devoid of background noise and hum. Keep the
GROUND LIFT SWITCH in the ground position if the noise level
remains the same in either position.
CAUTION: Do not terminate the AC ground on the unit in any
way. Termination of the AC ground can be hazardous.

Operation

1. After you have finished connection and placing the speakers in their
proper position, turn the POWER (10) on to the SP-1 (the POWER
LED (11) will glow) and the rest of your equipment.
Note: Turn on your equipment in the order that the sound
travels, beginning with the source and ending with the
amps.
2. Move the SOUND FIELD (15) control to the Circle Surround position,
then press the TEST (16) button on the SP-1. White noise will cycle
through each speaker (except the subwoofer) so that you may monitor
the levels of each speaker individually. While standing in the center of
the dance floor, check the noise levels with a sound pressure level
(SPL) meter or listen to the noise levels. Use the OUTPUT LEVEL (17,
18, 19, 20) controls to adjust the output level of the 4 channels. Note:
The REAR EFFECT LEVEL (14) is disabled in test mode. When
you've finished the test, use the SUBWOOFER OUTPUT LEVEL (21)
control to adjust the output level of the subwoofer.
Note: The subwoofer will work in all modes of operation and
is always on. Disconnect the subwoofer if you don't want to
use it. See the Bass Enhancer instructions for more
information.

Front Panel Controls

1. Volume Control: Use the VOLUME (13) control to adjust the overall
volume.
2. Rear Effect Level: Starting from the center position, use the REAR
EFFECT LEVEL (14) to adjust the rear speaker levels. You may boost
the rear channels if you feel not enough sound is coming from them.
You can also readjust the rear levels for music with varying spatial
information.
3. Sound Field: Use the SOUND FIELD (15) control to choose a mode of
operation.
4. Test Button: In Circle Surround mode, press the TEST (16) button on
the SP-1, and white noise will cycle through each speaker (except the
subwoofer) so that you may monitor the levels of each speaker
individually. The test button is recessed so you can not accidentally
initiate a test in the middle of your music program.
5. Output Level Controls: Use the OUTPUT LEVEL (17, 18, 19, 20)
controls to preadjust the output levels of the 4 channels to compensate
for different amps and speaker sensitivity. Use the SUBWOOFER
OUTPUT LEVEL (21) control to adjust the output level of the
subwoofer.
6. Bass Enhancer: Press the BASS ENHANCER (22) button to boost
the level of the bass of the subwoofer by +6 dB at 40 Hz. The Bass
Enhancer works optimally with most vented prosound subwoofers, and
when activated, special filters shape the frequency response to
optimize bass performance while cutting subsonic frequencies. Note:
the Bass Enhancer only boosts the bass from the subwoofer output.
7. Signal LED: The multi-color SIGNAL LED (12) indicates the level of
the signal and changes color incrementally from green to red. When
the SIGNAL LED (12) glows red, the unit is in overload, and you
should lower the VOLUME (13). Sometimes you can also stop an
overload by lowering the REAR EFFECT LEVEL (14) or the
SUBWOOFER OUTPUT LEVEL (21). Ideally, the SIGNAL LED (12)
should flash between green and orange.
Modes of Operation
Use the SOUND FIELD (15) control to choose one of the following modes
of operation:
1. Two Channel Stereo: In this standard stereo mode, the rear speakers
are disengaged and only the front speakers function.
2. Two Channel Four Speaker Stereo: In this four speaker stereo mode,
the rear speakers mirror the front speakers' program signal.
3. Two Channel Four Speaker Stereo Diagonal: With diagonal mode,
the rear right and left sides reverse so that the rear right speaker
mirrors the front left speaker's program signal and the rear left speaker
mirrors the front right speaker's program signal. This mode is useful in
large rooms or club environments to avoid people on one side of the
room hearing only one channel of a stereo program.
4.
Circle Surround: In Circle Surround sound mode, any
stereo signal can be used to generate surround play. A frequency and
phase dependent amplitude based signal processor uses ambiance
and directional information already present in the stereo signal to
generate 3D surround sound. And unlike other surround formats where
the rear output is mono and bandwidth limited, Circle Surround
separates the left and right rear channels with full bandwidth. In this
mode, the rear speakers will not output the full program (the rear levels
will be lower than the front), because the rear speakers are used to
create an enhanced spatial perception. Note: The Circle Surround
Experience is dependent on the source itself, therefore some tracks of
music may sound better in Circle Surround than others. Signals
encoded for Circle Surround will give you the best circle surround
experience.
Page 4

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