Acoustic Image Series II - Manual (Page 5)

with a maximum boost/cut of 15 dB. The brite control affects frequencies
between 6,000 and 16,000 Hz and provides a maximum boost/cut of 15 dB.
Notch/High Pass Filter
The notch/high pass filter is a fixed amplitude, variable frequency type that
inserts either an 18 dB cut or a 12 dB per octave rolloff at frequencies between
30 and 700 Hz , depending on the position of the control. The notch filter is used
to remove a given feedback frequency to reduce feeback “howl”. The high
pass filter is used to reduce the bass output in cases where room location or
instrument/pickup combination results in “boomy” sound. To use either, push
the on/off switch to turn on the filter circuit then select the filter type using the
notch/high pass switch. Start with the control fully counterclockwise and
gradually turn it clockwise until the desired effect is achieved, then experiment
with the position of the control to give you the sound you like best. The New
Yorker combo does not have the filter capability.
Effects Loop
Acoustic Image preamps have output (“Send”) and input (“Return”) capability
in each channel to allow you to use effects boxes. The send output is affected
by the input volume and tone controls and can also be used as a preamp output
for driving other power amplifiers. The Return input can be used to directly
connect an external preamp to the unit’s power amp. The effects level control
in each channel controls the volume of the returned (“wet”) signal relative to
the original (“dry”) signal. Because the effects loop is a parallel type, plugging
something into the send output does not interrupt the signal path. So, a tuner
can be plugged into the send output without affecting the signal going through
the amp. When the effects loops are not used, the level controls should be set
at zero. The New Yorker does not have the effects level control.
Direct Out
An XLR jack is provided for a Direct Out connection that allows the system’s
output to be fed to mixing boards of house PA systems or recording studios.
As a result, the instrument amplified by the unit can be recorded or further
amplified by the house PA system. In the Coda combos, the Direct Out signal
is the combined output of the mic and instrument channels and it is affected
by the input level and tone controls of each channel (post EQ). Any reverb
selected signal is also present in the direct out signal.
A ground lift switch is available to “lift” the ground from the output of the direct
out--reducing noise should a ground loop create hum when the unit is
connected to a mixing board. The New Yorker does not have the ground lift
switch.
Reverb (Contra R and Coda R only)
Our high-quality digital reverb units offer 8 program selections: 2 “Hall”
(Concert Hall and Arena), 3 “Room” (Club, Chamber and Garage), 2 “Plate”
reverb simulations (Plate and Vocal), and 1 “Spring” reverb simulation. With
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the Coda R, there are also switches to select which channel (mic or instrument)
has reverb added. If both switches are closed, the selected reverb setting
appears in both channels. A level control affects the level of the reverb signal
that is mixed with the “dry” signal to control the overall effect of the reverb.
You should experiment with both the reverb program selection and the level
control to find the sound that you prefer. When reverb is not used, the switches
for both channels should be off and the level control should be turned fully
counterclockwise.
External Speaker Jack
An extension speaker (ideally, the Contra EX) can be connected to the amp
to increase its output level, using the jack provided on your amp’s rear panel.
Speakers are connected via Neutrik Speakon connectors (“twist lock” type).
These connectors are used because of their low contact resistance and non-
shorting operation. The output of each Speakon connector is wired to pole “1”.
Make sure the cables you use to connect an external speaker are similarly
wired. Cables with Speakon connectors are available from Acoustic Image
if you are unable obtain them from your local music store. A 16-inch speaker
cable that connects the amp output to the speaker is supplied with the unit.
Spares are available from Acoustic Image.
The power amplifier is capable of driving speaker loads as low as 2 ohms. Use
a high quality speaker system in order to get the maximum performance from
the amp. The Acoustic Image Contra EX is an excellent choice.
The power amp is short circuit protected. If a short is connected to one of the
speaker jacks, the output signal will be interrupted until the short is removed.
If there is an intermittent short, the output will be interrupted for about one
second each time the short appears. However, the nature of a switching
amplifier makes it difficult to protect against shorts in all circumstances. To
be on the safe side, you should shut off the power to the amp before
connecting or disconnecting speakers from the unit.
Speaker Placement (Combos or Contra EX)
The omnidirectional low frequency output of the Coda, Contra, New Yorker
or Contra EX makes speaker placement relatively noncritical. You will easily
be heard all over the bandstand no matter where one or more are located.
However, best results are obtained when the cabinet is placed on the floor.
Putting the unit on a shelf or stand will reduce bass frequencies. There may
be circumstances where this is desirable. Again, feel free to experiment to find
the sound that is best for you.
Sound Lifter
In some settings, such as a hollow stage or small, “boomy” room, your amp
or enclosure will produce too much bass. One way to cut unwanted bass
output is to use the “Sound Lifter” peg to lift the front of the cabinet, reducing
the coupling to the floor. To do this, remove the lifter peg from the storage clip
on the bottom of the cabinet and screw it into the recessed nut on the bottom
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