BACK PANEL
EFFECTS LOOP
—A parallel effects loop is provided so an out-board effects processor can be used with or in
place of the on-board ALESIS® DSP unit. The return level from an external processor into the ¼” effects return jack
should be adjusted using the controls of the external processor. A ¼” effects cancel jack is provided on the back
panel to mute both internal and external effects via footswitch. Any standard single button latching footswitch (with
shielded cable) may be used. Signal is muted when the switch is closed. The on-board effects can be turned off by
using the program labeled “bypass”. All other on-board effects on the Shenandoah™ Acoustic 100 can be used in
conjunction with an out-board effects unit plugged into the effects loop.
ACTIVE EQUALIZATION
– Each channel of the Shenandoah™ Acoustic 100 contains a separate 3 band (with
sweep mid) active equalizer. These equalizers, similar to those found on professional sound consoles, are very
useful tools when used correctly. The corner frequency of the low frequency section is 125 Hz, shelving curve. This
frequency is particularly handy when dealing with low frequency feedback from a big dreadnaught guitar. A
combination of volume reduction and turning down the low frequency control will generally get good results.
Become familiar with the action of the controls since their effective gain range is quite large. The low frequency
control is also handy for adding some “bottom” to a baritone sax and “chunk” to a mandolin or mando-cello. The
corner frequency of the high frequency section is 8 kHz, shelving curve. This frequency is especially useful for
taming the bright harshness of some mandolins, violins, brass and reeds. It can also be used to help acoustic
guitars, cellos and fl utes cut through other players in loud club situations. The “sweep mid” section features 12 dB
of cut or boost with a bandwidth approximately 1 octave wide. The center frequency of this fi lter is continuously
user adjustable from 250 Hz to 5 kHz with a single control. This fi lter is typically (but not always) used to reduce or
remove offending frequencies in the instrument’s pick-up response. Removing only the minimum amount necessary
will yield the most acoustically rewarding results. The easiest and most repeatable way to determine the
offending frequency range is to boost the mid level somewhat (but not to the point of feedback) and while playing,
sweep the frequency control slowly across its range. You may need a third hand until it becomes second nature, but
soon you will fi nd out just how quick it can be. You will hear a clear and obvious accentuation of the ugliness you
want to remove. The ear is a most sensitive and discriminating piece of test equipment when used in this manner,
another good reason to protect them! This is the way many touring sound engineers equalize, since it is quick,
accurate and repeatable. Occasionally, you will fi nd need to use the mid section in “boost” mode, particularly
common when adding higher mids (bite) to an otherwise dull instrument, or adding low mid “body” to an otherwise
thin sound. Spend some time experimenting so that the process becomes creative as well as corrective.
MASTER VOLUME
– The master volume control adjusts the overall volume of channel 1, channel 2 and the
effects return (either on-board or digital). Typically, best results are obtained when this control is operated between
the 9:00 o’clock and 3:00 o’clock positions.
DIRECT OUTPUTS
– The Shenandoah™ Acoustic 100 contains the most comprehensive direct output section
available on any acoustic instrument amplifi er. Both XLR balanced and ¼” unbalanced outputs make “real world
sense” when connecting with other equipment. The ¼” unbalanced outputs are true professional line level (+4 dBv)
with an output impedance of 1k ohm, and can drive virtually any line level input, including power amplifi ers. The XLR
balanced output is “hot” mic level, rated at –30 dBv. This confi guration allows the Shenandoah™ Acoustic 100 to
drive very long cable lengths (250+ feet) without problems or added noise. The XLR balanced direct outputs can be
“ground lifted” with the global ground lift switch. This switch lifts pin 1 on all of the XLR balanced outputs to break
ground any loops between the Shenandoah™ Acoustic 100 and a PA system. Separate Channel 1 and Channel 2
outputs are post channel volume/pre effects (to take advantage of the dual inputs on each channel) while the
Channel 1+2 output is post master volume/post eq/post effects to aid in sending a “fi nished” mixed signal to a PA
system or external power amplifi er.
POWER AMPLIFIER
– The Shenandoah™ Acoustic 100 contains an advanced monolithic power amplifi er
3
