Using modulation effects are what turn a bland track into a fun and interesting one. Anyone in the music industry will surely agree that these effects have the power to add depth, texture, movements, and emphasis on various parts of a song. Though some effects could be very subtle, they can still make a big difference in the overall effect and feel of an instrument or vocals. This is why many engineers and artists have to learn how to create these effects and invest in the equipment that makes them.
Three Main Types of Modulation Effects
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Before we go into the different instruments used in modulation effects, it is important to first know the different effects there are and what makes them special. There are 3 main effects that can be achieved through modulation: phasing, flanging, and chorusing. All of these effects are achieved using a low frequency oscillator (LFO), but differ in delay time.
First, phasing effect has the shortest delay time and has the subtlest effect. This effect is achieved by canceling out different frequencies. This is done by splitting a frequency into two. One of them is retained as the original signal, while the other one is made slightly out of phase. The two signals are then combined again to cancel out the frequencies that are out of phase. With this, the frequency notches are spaced evenly across the bandwidth.
Flanging has the second shortest delay time of 1 to 5 milliseconds. It is used to create a sound that a lot of 1970s bands such as the Beatles loved. It also has the greatest frequency cancellations. This is achieved by feeding a modulated signal back into the input. Frequency notches are spaced harmonically across the bandwidth.
Chorusing has a similar process as flanging, but it has a delay time of 5 to 25 milliseconds. It is used to put more depth, width, and texture to a track which is why many 1980s bands loved using this effect. Its frequency notches are also similar to flanging.
Now that you have a basic knowledge of the main types of modulation effects, we can now discuss the equipment used to achieve them during mixing.
Devices Used to Create Modulation Effects
Phasers
A phasing instrument, also known as analog phaser, was originally used in the 1970s when digital delay electronics were still nonexistent. Back then, it was the only way to create any sort of modulated effect. Traditional phasers use various all-pass phase-shift networks to change only the phases of the frequency components of a signal. The amount of audio pass filters varies for different models, which can have 4, 6, 8, or 12 stages. Examples of an analog phaser are the MXR Phase 90 and Maestro PS1A Phase Shifter. Today, phasers are found as plugins in audio editing softwares.
Tape Flanging
Tape flanging was originally achieved in the 1960s by recording a song on two recorders at the same time. A time delay is achieved on one of the recorders by placing a finger on its tape flange. Both recorders are then played again and recorded as one track. This method was very expensive and inefficient because people had to use four recorders all in all. The old method was sooner replaced when modern technology made digital flanging possible.
Flangers
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This is an electronic device that came after tape flanging. One of the very first to come out was the MXR Flanger/Doubler which is one of the best-sounding bucket brigade flanging effects out today. This device works by passing the analog signal through a series of capacitors. The signal degrades as it passes each capacitor. This creates a unique tone to the signal. This device can be used for sound-shaping, recording, mixing, and post-production processing.
Chorus Devices
The chorus effect was made popular in the 1980s when Roland and their Jazz Chorus of guitar amplifiers were released. After this, chorusing became so popular and in demand that it was also made available for keyboards. It was when Roland introduced their Boss line of stomp boxes that made chorusing more efficient and easy to add in recordings. One model from the Boss line, the BOSS CE-1 Chorus, became one of the most popular chorus devices before it became available as a plugin. The chorus ensemble has been used and endorsed by countless artists in the 80s.