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When using multiple effects together, whether they be guitar
stompboxes or a few effects in a multieffect unit's patch, it becomes important to
"gainstage". Gainstaging is setting the gain (volume boost) of each stage
(effect) in your signal path. Many effects such as distortion pedals, equalisers and
compressors have the ability to boost or cut the signal level significantly and, if you
are not careful, it can be very easy to destroy your tone by introducing distortion or
unwanted noise.
The importance of levels
Effects are designed to work best at a particular small range of levels. If you are using
stompboxes or a guitar processor, this range will be the levels you can expect from an
electric guitar (approximately -40dB). Similarly, if you are using a big multieffect
designed for studio, the input and output levels will be designed to cope with the
standard "Line Level" (+4dB) used by most professional studio equipment. Once
the input signal exceeds this level, there is a very real chance that the inputs will clip
(distort) or the headroom will be severely limited. In the case of digital effects, this
clipping can be extremely nasty - typically a harsh clicking sound. Analog effects units
can also clip, and while they tend to do it a little more gracefully than digital, it
still degrades the signal.
Multieffect units also often have an adjustable output level,
which can drive a range of levels, from the low level suitable for a guitar amp's input,
to line level for direct into a power amp or mixer's returns. It stands to reason that if
you are driving a guitar amp, setting the output levels to +4dB would distort the
amplifier very heavily.
Low signal levels can also be a problem as it worsens the
signal-to-noise ratio (see box below), making the apparent noise level increase. It can
also affect on how many effects work - compressors, auto-wahs and many other effects
depend of the input level to determine how they should behave, so a low signal level can
make them behave completely differently.
| Signal-to-Noise Ratio Signal-to-noise ratio (often abbreviated as S/N) is the ratio between
the level of the signal and the level of unwanted noise. The noise of any device is
usually fixed, but if the signal level can be strengthened, the S/N improves.
What this means is that if you can raise the volume of the
signal, the sound you don't want (the noise) - such as the hiss from an effects pedal - is
quieter in comparison. Even simpler? Noise bad, sound good... got it? |
If the noise level of an effect stays constant, a
louder signal will have a better signal to noise ratio.
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How to gainstage
1. Set the input and output levels
If you are using a multieffect, the first thing to do is set the input and output
levels. The input and output levels will usually be switchable to choose the correct level
for what you are driving by giving the nominal level (-20db or "Low"
level, +4db or "High" level, etc.).
A processor designed specifically for guitar will usually
have a fixed low level input suitable for guitars, so you don't have to worry about the
input level, just set the suitable output level (sometimes given as helpful choices like
"Guitar Amp" or "Power Amp"). Some units may even have different
outputs for different types of amp.
If you have a fully adjustable output level, which lets you
set the output precisely anywhere between -60dB to +4dB, the first thing to do is turn all
your effects off, so the unit is supposed to be doing nothing to the sound and set the
level by ear.
If you are a guitarist driving the front of a guitar amp,
also compare the bypassed level (still no FX!) with the level of the guitar plugged
straight into the amp - If the effect unit is driving the amp too hard, it may be
difficult to get a clean sound as the amp will be driven into distortion. So you want the
output level of the effect to be more or less the same as the output level of the guitar.
Stompboxes will always be low level inputs and outputs, so no
setting needed there.
2. Set each effect's level
Turn off all effects first, then turn them on, one at a time and set the level of
the effect (if it has level adjustment - some, like chorus and phasing rarely have level
settings). Switch the effect on and off to compare the effected level with the bypassed
level, and adjust the effects level so it is the same as the bypass.
Now turn the effect you have just set off again and
move on to the next effect and do the same again. At the end of this, you should end up
with all your effects at more-or-less the same level.
Compressors (which even out differences in volume), can be a
little tricky to set. If you play softer, the compressor will boost the volume, and if you
play harder it will cut the volume, so can give you a false impression of level. The best
approach is to play at a normal level somewhere in between while you compare the effected
sound to the bypass.
| Equalisers are often set incorrectly. The important thing to remember with any EQ is that every band is a level
control - just operating on a specific frequency band.
Whatever settings you come up with (please do not just copy
my settings, as it's doubtful they will work for you), it is very important to centre the
adjustments around the middle of the range, as close to the 0dB line as possible. This is
as equalisers are more accurate in the middle of their range, so will sound better once
set correctly.
The top example the adjustments are all made upwards of the
centre (0dB) line
The second example is the same relative EQ settings, but this
time too far below the centre line.
The Final example, the EQ is set correctly, with all the
adjustments centred around the 0dB range. Once you have set the EQ something like the last
example, adjust the overall level to match the bypassed level as discussed with the other
effects. |
Equalisers should always be adjusted so the adjustments
centre around the 0dB line
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3. Setting for a volume boost
It's common practice to set up one effect to boost the level a bit when turned on -
this lets the player instantly jump out of a band mix for a solo. This is perfectly
acceptable, even desirable as long as you do not boost too much and distort the next
effect in the chain. |
