Effets et modulations

De nombreuses pédales d’effet peuvent être ajoutées et utilisées avec un thérémine.

Attention cependant, mieux vaut tester avant l’achat, car comme l’explique Thierry Frenkel : Le souci avec beaucoup de pédales et autres boitiers d’effets externes, c’est qu’ils sont souvent équipés d’un « noise-gate », un circuit qui coupe la sortie quand le signal d’entrée est très faible, pour éviter la propagation de bruits, souffle et parasites (souvent créés par les composants de basse gamme à l’intérieur de la pédale elle-même).

Ce qui peut être utile pour un guitariste « heavy-metal » peut être la mort pour une expression musicale sophistiquée de la main gauche du thérémine.

Mais tout d’abord, quelques notions de bases:

PEDALS POWER BASICS
Batteries
Downside : batteries quickly go dead, because the current is used when the jack cable is stuck into audio Input, even if the pedal is switched off.
Power supply
Voltage is measured in volts (V). If your power supply reads 9V, then it is a 9-volt power supply. Use a power supply with the same voltage rating as the pedal—not more, not less.

Current (Amperage) is measured in amps (A). A milliamp, or mA, is one-thousandth of an amp. The current rating on your power supply is the maximum it can supply. Less is okay, but not more.

Use a power supply with a current rating greater than the current rating of the pedal connected. If you are powering multiple pedals from a single power supply using a daisy-chaining cable, then add up all the current ratings of your pedals. Your power supply must provide more current than this total. Moreover, all the pedals in the chain must have the same polarity (center positive or center negative, more about that below).

Daisy chaining cable
AC/DC : Most pedals are DC (direct current). Pedals requiring AC (alternating current) usually come with a dedicated power supply, and it is recommended that you use only this power supply with the pedal.

Polarity : DC voltage has polarity, which simply indicates which conductor has positive voltage and which has negative. With a barrel-type power plug, this is usually specified as center-positive or center-negative. A center-negative plug will have the negative voltage on the center conductor and the positive voltage on the sleeve (outside) conductor.

center-positive
center-negative
Unlike most electronic devices, a 9V DC center-negative power supply is the standard for pedals. Nonetheless, always check your pedals before powering them up, as some have center-positive polarity. Best case scenario : the pedal won’t work. Worst case scenario :  the pedal will be killed, power-fried.

 

TYPES OF EFFECT

There’s a large panel of guitar / bass pedals available, affecting different sound parameters :
Gain & dynamics effects : Overdrive, Distortion, Fuzz, etc.
Theses pedals act on volume / level signal, to boost it. It adds a special color, from warmer and bigger sound, up to aggressive and saturated. Softer to higher impact is as follow :
Overdrive < Saturation < Distortion < Fuzz

give a sharper attack -> more percussive sound
reduces the possibility of playing pianissimo

Frequency effects : Pitch shifter, Octaver, Harmonizer, Arpanoid, etc.
Changes, transposes or adds notes to the reference note being played.

possibility of playing chords
stresses the off-key notes

Tone effects : Wha-wha, Filter, Equalizers, Talking Machine, etc.
Affects the tonal color, such as the bass and treble content.

Filter: alter the frequency content of an audio signal that passes through them by

either boosting or weakening specific frequencies or frequency regions.

Equalizer: set of linear filters that strengthen (« boost ») or weaken (« cut ») specific

frequency regions.

T. Machine : Vocal Formant Filter, presenting creative vowel shaping that is controlled by the

player’s dynamics

better results with waves full of harmonic contents
Time modulation & spatial effects : Reverb, Delay, Tremolo, Chorus, Flanger, etc.
Reverb : creates a sense of space around the sound : large rooms, small rooms, etc.

Delay : repeats the original signal.

Chorus : mimic the effect choirs and string orchestras produce naturally (slight

variations in timbre and pitch).

Flanger : reproduces  studio sound made when two tapes were mixed together and

one was delayed.

Phaser : creates a slight rippling effect

Tremolo : produces a slight, rapid variation in the volume of a note or chord.

soften the off-key notes (-> not good for practice)

Others : Looper, Line selector, Volume pedal, etc.
Looper : allows a performer to record and later replay a phrase or passage from a

song

Line selector : possibility of quickly switching settings among several effects devices

V. Pedal : allows to mute or increase sound without fiddling with the knobs

Looper: adds layers / melodies to monophonic theremin sound

LAST BUT NOT LEAST

Video demonstration with guitarists on youtube is not representative of how the pedal will affect the sound using a theremin. This is because the guitar audio signal and its level is very different from the theremin’s.
>always try the pedals with your theremin at the shop<

ask to borrow them for a day or two or inquire about policy return. Otherwise, you might end up very disappointed, as some pedals simply won’t be effective with the theremin signal.
Some pedals can be overloaded by theremin’s line level signal (which is much higher than the guitar level signal). A solution is to attenuate the signal with an inexpensive low impedance inline volume pedal.

Some distortion and fuzz pedals that can introduce noise into the audio signal when playing pianissimo. Some of these pedals have a “noise gate” to deal with this problem, which means the audio signal will be cut when playing pianissimo.
>Unless you want to play very percussive sound,

avoid buying a pedal with a noise gate<

Noise and signal overload issues mostly affect analogue pedals, digital tend to be ok.
The theremin sound does not have a lot of harmonic content (sine wave), so effects that use filters, such as wah-wah and EHX Talking Machine pedals have a much stronger effect if used in conjunction with a distortion or fuzz pedal that increases the harmonic content of the audio signal.

Switching the order of the pedals and the theremin’s sound settings can make tremendous difference on the sound produced.

 

 

 

Diverses modulations sont possibles, sur des paramètres différents :