Whether in the studio or on stage, as recordists or musicians
we all run into a situation eventually where one sound doesn't do the job. It might be a
distorted electric guitar sound which doesn't have the clarity needed. On the other hand,
the clean electric guitar sound might not have the punch you want. Wouldn't it be nice to
have a combination of both?
So you take two amps, set one to distort and the other to a
clean sound, then mic up and mix the two. Problem solved! This is the simplest example of
using two effects in parallel (remember, an electric guitar amp is an important part of
the electric guitar sound and, as such, is an effect). The analogue for a bassist is when,
in the studio, the engineer uses a DI box to get a direct sound while also driving a bass
amp and miking it up.
This is the usual
manner of connecting effects - from the output of one into the input of the next, into the
next, etc.. This is called series connection. Series connection is a perfectly valid way
of doing things, and has been used to create some of the effects sounds we all know and
love. However, if you only use series connection of your effects, you are limiting
yourself. There is a whole other world available to you in parallel effects.
When running effects in parallel, we drive the inputs of two or more effects with
the same source signal (such as the electric guitar or bass in the example) by splitting
it into two or more 'branches'. Then the outputs of the two can be recombined using a
mixer. This gives a range of sound combinations not available with series.
Of course, it need not stop there. Now it is possible to treat each
branch as an effect chain. Each can also be EQ'ed differently at the mixer and panned to
different positions in the stereo soundstage for a really large, spacious sound.
For recording, you can record each on two separate tracks on
a recorder. This allows you to decide how to mix things later in the mixing process, when
you have a better idea of what will work best in the song. For a guitar signal, another
option is not to mix them back together, but to drive two different amplifiers.
Splitting the Signal
In a perfect world, you would be able to use a simple splitter cable to split the
signal into two branches. Unfortunately, the inputs of many effects do not play nicely
with others, and one may 'snatch' all the signal for itself, leaving nothing for the other
effect. There are a few ways of getting around this.
- Splitting buffers or 'Spluffers' - these are
specially designed for parallel effects usage. They consist of two identical buffer
preamplifiers in one box which have separate outputs but share the same input.
Unfortunately they are not very common and must usually be built to order.
- DI boxes - using two identical DI boxes and a
splitter cable is essentially the same as a spluffer, but is more easily available.
- Stereo Mixers - using a stereo mixer is another
option. Pan your input to the centre and the left and right outputs are identical buffered
signals. You could also use spare auxiliary channels or output busses on your main mixer
if you have them to spare.
- Stereo effects - many effects such as delay, chorus
and autopanners are by their nature stereo and have separate outputs for each channel. A
delay can be set to a short delay of a few milliseconds (be aware that this can change the
tone quite radically, so experiment with finding the right delay time which works for
you), and similarly, chorus can be set to be relatively subtle.
A Few Ideas
Here are two of my favourite parallel effect tricks:
Instruments with two separate outputs - If you have
an electric guitar with a piezo bridge, you can use this to drive a second effects chain.
A similar thing is to have a two pickup electric guitar or bass modified, so that each
pickup feeds it's own output jack. Even if you don't process the two branches separately,
combining the two with a mixer gives you a different sound than doing so with the passive
switch in the instrument This works especially well when you have an instrument where each
pickup sounds great by itself, but has a nondescript sound with both together.
Dynamic delay - I will often compress one branch and
use a delay on the second. When I play softly, the compressed branch stands out as the
compressor is boosting the level. As I play harder, the louder the delayed branch becomes,
while the compressed one stays at a constant level. This means that the delay only becomes
audible as I accent beats. This trick works with almost any effect on your second branch.
If you use a stereo delay and pan it hard left and right while the compressed
branch is panned to the centre, the delays bounce around the extremes, with the compressed
sound rock solid in the centre.
Comb filtered branches - Use a graphic equaliser on
each branch. On the first EQ, cut every second frequency band by about 6dB or more and
boost the other bands by the same amount. Now reverse these settings on the EQ on the
second branch. This gives you two totally different tonalities, which fit together
perfectly in a mix. For a guitar sound, try adding overdrive to each branch (either before
or after the EQ - it will sound quite different depending on the order).