Genz-Benz 80 LT Musical Instrument Amplifier User Manual


 
ACTIVE EQUALIZATION - The Shenandoah
®
Stereo 80LT contains a 3 band (with sweepable mid) active equalizer on
both channels 1 and 2. These EQ networks, similar to those found on professional sound consoles, are very useful tools
when used correctly.
LOW FREQUENCY EQ - 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 re-
duction 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.
HIGH FREQUENCY EQ - 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 utes cut through other players in loud club situations.
MID FREQUENCY EQ - The “sweepable mid” section features 15 dB of cut or boost with a bandwidth approximately 1
octave wide. The center frequency of this lter is continuously user adjustable from 250 Hz to 5 kHz with a single con-
trol. This 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 nd out just how quick it can be. You will hear a clear and obvious accentua-
tion 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 nd need to use the mid section in “boost” mode, particularly com-
mon 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. The 9 o’clock position is 300
Hz, the 12 o’clock position is 1.25 K Hz and the 3 o’clock position is 3 K Hz.
MASTER VOLUME - The master volume control adjusts the overall volume of channel 1, channel 2 and the effects return.
Typically, best results are obtained when this control is operated between the 9 o’clock and 3 o’clock positions.
REAR PANEL
DIRECT OUTPUTS - The Shenandoah
®
Stereo 80LT is equipped with left and right XLR balanced direct outputs
and unbalanced ¼” line level outputs. The left direct output also serves as a mono send. Both the 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 ampliers. The XLR balanced output is “hot” mic level, rated at -30 dBv. This
conguration allows the Shenandoah
®
Stereo 80LT to drive very long cable lengths (250+ feet) without problems or
added noise. The XLR balanced direct outputs can be “ground lifted” with the switch provided. This switch lifts pin 1
on the XLR balanced output to break any ground loops between the Shenandoah
®
Stereo 80LT and a PA system.
Both outputs are post master volume/post EQ/post effects to aid in sending a “nished” mixed signal to a PA system
or external power amplier.