Acoustic Image Flex - Manual (Page 7)

10
Filter
Headphone
Amp
I/O Buss
d-Rear Panel
Output to
Flex Cab
(RJ-45)
Phase Inv
Spkr Em
(Optional)
Filter
Phase Inv
Spkr Em
(Optional)
Effects
Prog Select Level Rate
Ch 2
jumper Effects
On/Off
Effects
On/Off
Gnd Lift
Direct Out Pre/Post
10 db
Pad
Master
Level
Mute
Rear Panel
Snd Rtn
DC in
18V 400mA
H/P
Effects Loops Pre amp Out Stereo Out
Limiter
Off On
L
R
Ch 1
Ch 2
Sig/Pwr
Interface
11
Level
Tone
The input level controls the level of the signal at the input stage of the
preamp. The master volume controls the level of the signal at the
output of the preamp (at the input of the Flex Cab or other powered
cabinet). Set the master control at “12 o’clock” and the input level at
zero. The input level should then be used to control the overall output
of the unit. The two controls are provided to allow independent control
of “house” volume and “stage” volume when the unit is used as a stage
monitor with a connection to a house PA. See the discussion under
“Direct Out” below.
If you have an instrument with a particularly “hot” output such as an
active bass guitar and you find that the front end of the preamp is
clipping or being overdriven, a 6 dB gain reduction option is available
via a jumper on the preamp control printed circuit board. How do
access and utilize this option is described in “Jumper Options” section
found on page 15.
Each tone control has a center detent at the flat position. Experiment
with the controls to achieve the frequency balance that sounds best to
you. In general, small values of boost and cut are best. The Flex Pre
is designed with flat frequency response so only minor corrections
should be required to compensate for room effects or “peaky” pickups
in order to maintain the balanced response desired for acoustic
instrument amplification. To minimize electronic noise, avoid
operating all controls simultaneously at their maximum settings. The
Low control is a shelving-type that affects frequencies below 150 Hz
and with a maximum boost/cut of 12 dB. The Lo Mid control affects
frequencies between 70 Hz and 700 Hz (peak at 250 Hz) and has a
maximum boost/cut of 12 dB. The Hi Mid control affects frequencies
between 700 Hz and 3000 Hz (peak at 1200 Hz) with a maximum
boost/cut of 12 dB. The Hi control is also a shelving-type that affects
frequencies above 3500 Hz with a maximum boost/cut of 12 dB.
The Flex Pre has a sweepable low cut filter and phase reverse switch
in each channel. The low cut filter is a variable frequency type that
inserts a 12 dB per octave rolloff at frequencies between 30 and 150
Hz, depending on the position of the control. The low cut filter is used
to reduce the bass output in cases where room location or
instrument/pickup combination results in “boomy” sound. Press the
on/off switch to turn on the filter circuit. Start with the frequency control
fully counterclockwise and gradually turn it clockwise until the desired
effect is achieved. The frequency range of the control is limited in
order to give you more control in the critical low frequency range. As a
result, the effect you hear in normal circumstances may be subtle, but,
Low Cut Filter/Phase Reverse/Speaker Emulation Filter