Hi, I am Rasheeq Rayhan from Dhaka, Bangladesh. This lesson is for week 6 of

Introduction To Music Production at Berklee College of Music. I will be explaining the

usage of the 5 most important synthesis modules: Oscillator, Filter, Amplifier,

Envelope, and LFO.

A sound synthesizer (often abbreviated as “synthesizer” or “synth”) is an electronic

instrument capable of producing a wide range of sounds. Synthesis may either imitate

other instruments (imitative synthesis) or generate new timbres. They can be

played/controlled via a variety of different input devices (including keyboards, music

sequencers and instrument controllers). Synthesizers generate electric signals

(waveforms), and can finally be converted to sound through the loudspeakers or

headphones.

Synthesizers use a number of different technologies or programmed algorithms to

generate signal, each with their own strengths and weaknesses. Among the most

popular waveform synthesis techniques are subtractive synthesis, additive synthesis,

wavetable synthesis, frequency modulation synthesis, phase distortion synthesis,

physical modeling synthesis and sample-based synthesis.

The front panel of

most synthesizers

contains a collection of

similar signal generating

and processing modules

– coupled with a number

of modulation and

control modules. The

signal-generating and

processing modules

typically run left to right, mirroring the actual synthesizer signal flow

Oscillator:

The audio signal of a synthesizer is generated by the Oscillator. It is a device for

creating an electrical pressure soundwave. The sound source part of a synthesizer will

contain one or more Oscillators. They create waveforms by adding voltage together in a

manner comparable to the way harmonics in air pressure soundwaves combine to

create complex natural soundwaves. Here is a photo of the oscillator of Native

Instrument’s Massive:

Usually you would choose from a selection of waveforms that contain different types

and varying amounts (more or fewer) of harmonics. The level relationships between the

fundamental tone and the harmonics of the chosen waveform are responsible for the

basic sound color/timbre. The qualities of the most common synthesizer waveforms

are:

Sine Wave: Clean and clear-sounding, a sine wave contains no harmonics but the

first harmonic; in other words, it is the fundamental tone, energy at a single frequency.

The sine wave—used standalone—can be used to create “pure” sounds like whistles,

the sound of wet fingers on the rim of a glass, tuning forks, and so on.

Sawtooth: Clear and bright-sounding, a sawtooth wave contains both odd and even

harmonics. It is ideal for the creation of string, pad, bass, and brass sounds.

Square Waves: Hollow and woody-sounding, a square wave can contain a wide

range of odd harmonics. It is useful when creating reed instruments, pads, and basses. It

can also be used to emulate kick drums, congas, tom-toms, and other percussive

instruments—often blended with another oscillator waveform, such as noise.

Triangle: Like a square wave, a triangle wave contains only odd harmonics. Because a

triangle wave’s higher harmonics roll off faster than the ones of a square wave, the

triangle wave sounds softer. It is ideal for creating flute sounds, pads, and vocal “oohs.”

Noise: Noise is useful for emulating percussive sounds, such as snare drums, or wind

and surf sounds, among others. It contains all frequencies—at full level—around a

center frequency.

Filter:

The purpose of the filter in a synthesizer is to remove portions of the signal—the

frequency spectrum—that is sent from the oscillators. After being filtered, a brilliant-

sounding sawtooth wave can become a smooth, warm sound without sharp treble.

The filter sections of most synthesizers contain two primary controls known as

cutoff frequency—often simply called cutoff—and resonance. Other filter parameters

can include drive and slope. The filter section of most synthesizers can be modulated by

envelopes, LFOs, the keyboard, or other controls such as the modulation wheel.

There are several filter types. Each has a different effect on various portions of the

frequency spectrum:

• Lowpass filter: Low frequencies are passed; high frequencies are attenuated.

• Highpass filter: High frequencies are passed; low frequencies are attenuated.

• Bandpass filter: Only frequencies within a frequency band are passed.

• Band Reject filter: Only frequencies within a frequency band are attenuated.

• Allpass filter: All frequencies in the spectrum are passed, but the phase of the

output is modified.

Here is the filter section of Massive:

Amplifier and Envelopes:

The amplifier module of a synthesizer is responsible for controlling the level—or

loudness—of the signal over time.

To put this into a musical context, consider the sound of a violin, which slowly

ramps up to a peak—or maximum—level as the bow is smoothly dragged across a

string, is sustained for a period until the bow is moved away from the string, and then

cuts off abruptly. In comparison, hitting a snare drum with a drumstick results in a very

fast peak level, with no sustain portion, and the sound immediately dies out (although

there will be an amount of decay, the time it takes to fall from the peak level). As you can

see, these two sounds have very different characteristics over time.

Synthesizers emulate these sonic characteristics by providing control over different

parts—the beginning, middle, and end—of a sound’s level over time. This control is

achieved with a component called an envelope generator.

The envelope generator usually features four controls—attack, decay, sustain and

release, commonly abbreviated as ADSR.

• Attack: Controls the time it takes for the initial slide from an amplitude of zero to

100% (full amplitude).

• Decay: Determines the time taken for the subsequent fall from 100% amplitude to

the designated sustain level.

• Sustain: Sets the steady amplitude level produced when a key is held down.

• Release: Sets the time it takes for the sound to decay from the sustain level to an

amplitude of zero when the key is released.

If a key is released during the attack or decay stage, the sustain phase is usually

skipped. A sustain level of zero will produce a piano-like—or percussive—envelope, with

no continuous steady level, even when a key is held.

Here is the Envelope section of Massive:

LFO:

Low Frequency Oscillator or LFO, modulates the original signal, but at a Frequency

(Hz) under the hearing range - 20Hz aprox. So the signal from the LFO is not heard, but

modulates the original signal creating a Vibratto effect.

Modulation is used to breathe more life into a sound and make it more expressive.

Basically, it is an oscillator working in a range of subsonic frequencies. It acts directly on

the generator.

Here is the LFO section of Massive:

I hope you enjoyed the lesson as much as I enjoyed making it. If you have any

questions do not hesitate to discuss with me so we can learn together! Thank you for

critiquing. Also, if you want to know more about my music, please visit my YouTube

channel. J

https://www.youtube.com/user/FrenzyPhrenesis

Regards, Take Care and Happy Learning!