Looping acoustic instruments

[matthias@bahianet.com.br (Matthias Grob)]

Here are some proposuals to help colegues who want to loop accoustic
instruments like percussion. It is written for the ECHOPLEX, but should be
similar for other machines.

The problems are:

a) The difficulty to hear the correct volume of the instruments and mix
them correctly into the loop.

b) The danger of feedback. Even if the volume is not as high as to create a
oscillation, sound from the monitor enters the mike again and is recorded
again into the loop, deteriorizing the sound quality and making clean
Replace impossible.
Pressing Overdub really just while playing improves this situation a lot.
The Overdub Mode SUS helps to this.

c) Crosstalk from other instruments and noises into the loop. If the drums
is playing next to the percussionist or loud in the monitor, the snare will
we looped. Whether this is a problem or not depends on the music and the
way the loops are used.

d) The physical distance of the instruments and the various postures of
playing difficult the position of the pedal board.
ECHOPLEX pedal boards can be used in parallel. You can have the keys in
several places, even in several forms (to operate by knee or elbow, for
example)


Basically there are three ways to go:

        1. A microphone/sound system only for the loop

This is the most simple, suitable for rehearsals, small shows:
Connect a clip microphone directly to the ECHOPLEX and keep clipping it to
the instrument you want to loop. You can prepare a piece of wood on each
instrument so you know exactly where to clip the mic and how loud it is
going to be.
Mark the correct position of the Input control for each instrument so you
can adjust it quickly before you play.
Wind up the Mix control to "loop".
Connect the ECHOPLEX output to some amplifier (preferably not a guitar
amp!) and regulate the volume, so the instruments appear about equally loud
direct and from the loop. The sound will not be the same, but this can be
interesting even.

        2. Mixing on stage or by the bands sound man

The musician or a smart sound man controls the loops form the mixing desk.
The sound can be equalized for each instrument and monitorized. Thus, the
difference between the original and the looped sound becomes small.
The ECHOPLEX is connected like a reverb to a Aux send and returns to a
channel (remember to close the Aux in that channel!). The MIX control is
way up to "loop".
The problem is the position of the Aux send control in every channel. To
optimize cross talk, the sound man should only open the channel that is
actually going to be looped.
With this setup you can for example maintain a groove on the congas (Aux
closed) and throw a cymbal into the loop (Aux open) without having the
congas looped (except cross talk).

The most perfect solution: Headphones (getting popular anyway!).


        3. "Electric" percussion instruments:

Could be MIDI sounds, but that's to cold, sometimes.
Instruments like Korg WaveDrum are much better, because they bring details
of playing techniques through that cannot be recorded by MIDI, but very
well in the loop, because there is no problem with noises and feedback.

Maybe we should start inventing "electro-acoustic" percussion instruments
in the sense of a electro-acoustic guitar: Little resonance and a pick-up
in the right place. The sound can become richer, easier to amplify and the
instrument can be played very dynamic.
Also, a simple piece of metal that has no volume but maybe an interesting
sound can turn into a new instrument.
In general, this type of instruments will be lighter and smaller, need less
stands, less space on stage, can be accessed more imediately.
Piezo pick-ups are cheaper than good microphones, need no clamps.
Mixing desks with piezo inputs (impedance >1MOhm) are not common yet, but
most ordinary ones can be modified easily.

This is the most futuristic way. It will take time and efforts, but we will
end up there.

Matthias Grob    Salvador, April 96