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StereoOperation
Note that channel 2 will not be heard through the speaker
system unless the Ch 2 switch is in the depressed or on position. If you
are nothearingchannel 2in theoutput, checkto besure thatthe switchis
on.
Effects(Coda RandCorus only)
The two-channel preamp of the Coda R and Corus can be operated in stereo
mode. When it is in the “on” position, the switch labeled “Ch 2” connects the
channel totheinternal poweramp andspeaker.When itis inthe“off” position,it
is disconnected from the internal amp but is accessible from the channel 2
send output. By connecting the send outputto a satellite power amplifier (such
as our Focus SA),and putting the switch in the off position, the preamp
operates in stereo mode. Note that channel 2 remains in the direct out signal
even when the switch is in the off position. This is done since stereo operation
is typicallya “stage”mode butnot a“house” mode (housesystems aretypically
not stereo).
Our high-quality effects units (which use the Alesis DSP chips) offer 6
program selections: 3 reverb programs (Hall, Room and Plate), a delay, an
ambient chorus and a flanger. There are switches to select which of the two
channels areprocessed bythe effects unit.Either channelcan beconnected to
theeffects unit.Ifboth switchesare engaged, theselected programappearsin
both channels.Alevel control affects the level of the reverb signalthat is mixed
with the “dry” signal to control the overall effect of the selected program. You
should experiment with both the program selection and the level control to find
the sound that you prefer. When effects are not used, the switches for both
channels should be off and the level control should be turned fully
counterclockwise.
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 wiredto pole “1”.
Make sure the cables you use to connect an external speaker are similarly
wired. Cables with Speakon connectors are available fromAcoustic Image if
youare unableobtainthem fromyour localmusicstore.
The poweramplifier is capableof driving speakerloads aslow as 2ohms. Use
a high quality speaker system in order to get the maximum performance from
theamp.TheAcousticImage ContraEX isanexcellent choice.
The power amp is short circuit protected. If a short is connected to the
extension speaker jack (or if the internal speaker is shorted), the output signal
will beinterrupted untilthe shortis removed. Ifa shortis present,you will heara
ticking sound at 3 to 4 second intervals which indicates that the short circuit
External SpeakerJack
protection is working.
The omnidirectional low frequency output of the Contra, Coda R, Corus 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 wherethis is desirable.Again, feelfree to experimentto find the
soundthat isbestfor you.
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 built in tilt back feature to lift the front of the cabinet, reducing the
coupling to the floor. To do this, pull the stand into its forward position and set
the comboin place onthe floor.The stand isspring loaded sowhen you pickup
theunit, thestand willspring backinto itsstorage position.You maywant touse
the tiltstand atall timesin order toaim thehigh frequency outputof thespeaker
towardyour earsothat youcan betterhearthe amp.
Anon-off switchfor thetweeteris mountedon theback panelofthe combounit.
Try the unit with the tweeter on and off to decide which sounds best to you.
Since the tweeter covers only the last octave of the musical spectrum, you will
findits effect tobe subtle,particularlywith bassinstruments.
So, what’s thedifference between the Corus and the CodaR? The Corus uses
a different wooferthan theCoda R.It ismore efficientand hasslightly lessbass
response. When coupled with the other speakers inthe three-way system and
after the crossover is adjusted for the higher efficiency of the woofer, theresult
is still a flat response like the Contra and Coda R but the low frequency 3 dB
point is higher (60 Hz versus 40 Hz) and the overall efficiency of the system is
higher (94 dB versus 90 dB). Thus the Corus is more optimized for non bass
instruments than the other combos. In particular, guitar players will like the
sound of the Corus. The higher efficiency gives it a more “forward” sound that
guitarists prefer. The slightly higher lowfrequency cutoff is not noticeablewith
guitarand otherinstruments.
The Corus combo has a gray front panel and a gray front grill so that it looks a
littledifferentand canbe easilydistinguishedfrom theothercombos.
Acoustic Imagecombos and cabinetsare madefrom injection moldedpolymer
materials. A little care will keep yours looking new for years to come. Use a
clean, dry cloth to clean the cabinet and metal parts of the amplifier.
To be on the safeside, you should shutoff the power
tothe ampbeforeconnecting ordisconnectingspeakers fromthe unit.
TiltMechanism
Speaker Placement(Combos or ContraEX)
Tweeter Switch
Description of the Corus Combo
Care
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