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N.B. Playing PASSIVE basses with the instruments own volume control turned back will
reduce the upper frequency response of the instrument, so try to keep this control well
advanced, using the amplifiers OUTPUT LEVEL control to provide for larger changes in
volume.
Mid Pre Shape
The MID PRE SHAPE facility is like a preset graphic equaliser built into the unit that you
can switch in or out to modify the sound of the bass.
This will add extra punch to your sound and may be used with or without the graphic
equalisation section being switched in.
The MID PRE SHAPE may be switched IN and OUT with the MID PRE SHAPE push
button switch on the front panel.
Graphic Equalisation
A GRAPHIC EQUALISER is a very flexible way of altering the sound of a bass guitar, and
if properly used will provide an extremely powerful method of tone shaping for your
instrument.
The GP7 graphic equaliser has been specially designed for the tone shaping of a bass,
and is more powerful and very different to the kind of graphic equaliser found for
instance on a Hi-Fi. Because of this there are a few rules to observe in its use.
1.
Do not fully boost just one frequency band as this will tend to emphasize a small
range of notes on the bass producing a PEAKY and not very usable sound.
2.
Do not boost or cut all frequency bands as this will just produce an overall change
in volume with very little tonal alteration.
3.
Do not use excessive bottom (50Hz) boost unless your speakers can handle it
(very few speaker systems are capable of handling frequencies as low as this with
any degree of efficiency).
4.
Do not use excessive top boost; this will tend to add a lot of hiss to the sound
(especially with ACTIVE instruments).
Useful Observations
The fundamental frequency range of a 4 string bass guitar is from 41.2Hz (bottom E
string) to around 392Hz (two octaves up on the G string) not a very wide range.
Obviously a lot of harmonics are produced when playing and these can extend up to
5Hz or more.
Other frequencies are produced by the attack portion of the note when the string is first
struck. This attack can be emphasized by boosting the top end.
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