This type of pedal (the famous Octave OC2, by Boss), is an effect that adds one octave to any note played (or even two octaves). Its purpose is to broaden the sound (when set to the minimum) or to have another note besides the one played. This type of effect is commonly used by bass players, who prefer it because it can offer some particular sounds.
In the stave below you can see the function of the octave.
It's best to install it in-line immediately after the Wha-Wha and before the other effects.
This effect, which can also be called a pitch shifter, recreates a pre-programmed pitch from a duplicate of the original note. Depending on the power of the machine, the transposed pitch can vary from a few hundreths of a tone up to two or more octaves. The procedure is shown below.
The part played develops these four notes: C, E, F and D. The machine was set to duplicate the notes one-fifth above, according to the
interval rules. Every note played will be accompanied by its fifth interval, produced by the processor.
Note C is alongside G, E with B, F with C, and D with A.
Depending on how the equipment is adjusted, the actual notes can stand out with respect to the processed notes, the opposite, or keep them at the same volume.
This is possible thanks to the various types of control that the processor has.
You need to pay attention to the types of intervals because it's possible to get duplicate notes. In fact, the programmed transposition
on a given interval occurs on any note, independent of the relationship with the tone of the song being playing.
Let's use an example of an improvised solo played in C major. If the pitch shifter sets an interval of a third major above (or other perfect intervals, major, minor, diminished or augmented), every third major note will be overlapped, as seen below.
As you can see some extraneous notes have appeared on the scale, therefore dissonant with the root in question, which in our case is C major.
It's clear that an effect of this type should be regulated and used with skill.
A pitch shifter also has other purposes: the creation of chorus effects, or particular delay.
We will now look at some typical controls found on a common pitch transposer.
The pitch regulates the half-step effect. Generally the characters are roman numerals, using the following regulation criterion:
In some equipment the control can be in hundreds: 0, 100, 200, 300 and so on. In this way the relationship of the duplicated notes will be more precise.
Usually, a good quality pitch transposer can produce two or more duplicates of a note, which can be individually regulated to your liking.
The fine regulates the transposition of the note on a micro-tonal level. It basically operates slighty out of tune, with the negative values decreasing and the positives increasing.
This control is very important because it serves to correct any out of phase harmonic imperfections in the duplicated note, and more importantly for the programming of a chorus effect.
The level regulates the volume of the effect with respect to the original sound, emphasizing low values.
The pan is used to set the effect on the right or left channel.
It is very important to set the effect on one channel if the duplicated note is quite distinguishable, but if you want to obtain a homogeneous and compact sound you can overlap
the original sound, positioning the effect at the center.
With the delay we set the delay of the note with respect to the original. Normally, a duplicated note is played at the same time as the actual note.
With the delay we can postpone the duplicated note by milliseconds, in order to make a succession of artificially created notes of that sound. Here is an example.
In this example, the C note was played with the metronome set at 100.
The first duplicated note is E, the third major of C with a delay of 150 ms. The second note is B (second minor below) with a delay of 300 ms, and the last note is G (fifth perfect) with a delay of 450 ms. Set the feedback delay to 0 on every harmonized note so that each note only repeats once.
Playing the C note in time, the pitch shifter will repeat the series of notes as programmed. We will talk more in depth on this topic in the section dedicated to delay.
The harmonizer:
the intelligent pitch shifter
We have seen that the pitch shifter duplicates the note by harmonizing it in the programmed way, without considering possible tone differences that it is working on, possibly forming various false or wrong notes. Instead, the harmonizer works in relation to the harmony. The main difference between the two types of effects is that the harmonizer asks what scale must the note be harmonized. In this way all intervals relating to the same scale are respected. The simplest thing is to see a practical example of it.
On the left is the E minor harmonic scale, in the center the same scale harmonized by the pitch shifter one third major above, while to the right the same E minor scale harmonized one third above. Look at the difference in the notes of the two harmonizations. The pitch shifter has harmonized every single note one third major above, often leaving the root in question (scale of E min harm). The harmonizer instead has been set to play every third note in the scale of E min harm and therefore, during the harmonization,
remembers the tonal ratio of the duplicated notes.
Modern signal processors usually contain both types of effects, each of which has its own job. Summarizing, we can say that the pitch shifter
is often used for duplicating the octave notes, to create the chorus, or to harmonize the notes with other types of intervals, where a more precise job is done by the harmonizer.
Practice will therefore be a great help when working with these two types of effects.
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