Audio Production

Question 1

What does VCO stand for?

Answer 1

Voltage Controlled Oscillator

Question 2

What does VCF stand for?

Answer 2

Voltage Controlled Filter

Question 3

What does VCA stand for?

Answer 3

Voltage Controlled Amplifier

Question 4

What is the difference between an analog vs. digital synthesizer?

Answer 4

An analog synthesizer creates an electrical signal and modifies that electrical signal through circuitry. There is NO COMPUTER on an analog synthesizer. Digital Synthesizer create signal through computer code and turn that code into an electrical signal.

Question 5

What does an oscillator do?

Answer 5

Oscillators are the section on a synthesizer that generate sound. They are the basic building blocks if synthesis. Often called (VCO’s Voltage Controlled Oscillators, DCO’s Direct Controlled Oscillators).

Question 6

Oscillators can produce a variety of common _______ types that can be used to create sounds

Answer 6

WAVEFORM

Question 7

What is a filter?

Answer 7

A filter removes a desired range of frequencies from an input signal (either analog or digital)

Question 8

What are the five different filter types?

Answer 8

Low-Pass Filter: Low frequencies are passed, while high frequencies are attenuated. (make the sound muddier)

High-Pass Filter: High frequencies are passed, while low frequencies are attenuated. (make the sound tinnier)

Band-Pass Filter: Only frequencies within a specified frequency band are passed. (focus your sound a specific section)

Notch Filter: Rejects one specific frequency from the output signal(production tool to get rid of unwanted noise in a frequency).

Comb Filter: Creates multiple pass bands that are similarly distanced across the spectrum, giving the output signal a comb-like appearance(for creating timbrally interesting sounds)

Question 9

What is a VCA?

Answer 9

A voltage controlled amplifier, or VCA, is an amplifier whose gain is set by the voltage level of a control signal.

In many synthesizers, a VCA (or a digital equivalent) is the last functional block that a signal goes through before being sent to the synth’s output;

the VCA determines the instantaneous volume level of a played note, and it quiets the output at the end of the note.

If a synth does not contain a VCA, its outputs would sound continuously!

Question 10

What is Hard Sync?

Answer 10

This is commonly referred to as Oscillator Sync.

Oscillator sync, sometimes called ‘hard sync’, is achieved when one oscillator, called a master oscillator, is plugged into the sync input of second oscillator, known as the slave oscillator.

Each time the master oscillator’s cycle repeats, it resets the cycle of the slave. When the slave’s frequency is set slower than the master’s frequency, the slave is forced to repeat before it finishes a complete cycle

Question 11

What is slew?

Answer 11

Slew is a method of smoothing out a signal by providing logarithmic/exponential shapes to changes in voltage.

Question 12

What does the tuning section of the synthesizer do?

Answer 12

Tuning refers to the raising or lowering of pitch on a synthesizer. They are typically in two different varieties - course tuning and fine tuning.

Course tuning is a knob that tunes over the course of the hearing spectrum (20 Hz - 20,000 Hz)

Fine tuning is a knob that generally tunes over an octave. For smaller adjustments and precise tuning.

Question 13

What is PWM in synthesizer terminology?

Answer 13

Stands for Pulse Width Modulation.

While a square wave has equal time between maximum voltage and minimum voltage, a pulse wave is essentially a square wave with an adjustable amount of time in between each cycle before the the voltage drops from maximum to minimum.

The percentage of time that the signal is high is known as a duty cycle.

Question 14

What does modulation let us REALLY do in plain terms?

Answer 14

It lets us wiggle a part of synth.

Question 15

What does CV do?

Answer 15

Sometimes abbreviated CV, Control Voltage is a DC electrical signal used to manipulate the values of components in analog circuits.

Control voltages are used in numerous ways in many different types of electronic circuits for all sorts of purposes.

If you send a specific electrical voltage to a module of an analog synthesizer, you can specify what you want the module to do (so in our previous example where we were talking about the envelope controlling volume, we could could change that envelope to have it lengthen the decay time).

Question 16

What are the 2 most common types of control voltage sources?

Answer 16

LFO’s and Envelopes

Question 17

What is an LFO?

Answer 17

Low Frequency Oscillator (LFO). As the name implies, an LFO is an oscillator that operates far more slowly - usually below the range of human hearing (sub 20Hz).

It usually can’t be heard in itself in the signal path - it’s used to control other synth parameters instead.

All of the basic wave shapes that we have come to know and love can be used as an LFO.

LFO’s will continuously change the sound meaning that when the cycle is finished, the LFO will repeat.

Question 18

What is an Envelope?

Answer 18

An envelope is a time-based control that traditionally controls the amplitude of a synth’s oscillator over time.

Question 19

What is sample and hold?

Answer 19

A Sample and Hold LFO is one of the best ways to automatically create movement within a patch if you are ok with adding randomness into your synth patch.

It randomly samples noise and holds it out based on a clock source (lfo, env, gate)

Question 20

What are some really popular places to route an LFO?

Answer 20

Common places to use CV control on your synthesizer are:
VCA FILTER CUTTOFF PWM TUNING
VCO FILTER RESONANCE MIXER LFO
BANK FILTER INDEX PATCH MIX OF EFFECTS

Question 21

Attenuverters:

Answer 21

Very similar to volume knobs but at 12 o’clock, they have NO affect on the incoming signal.

Question 22

Analog:

Answer 22

Circuitry that uses a continually changing voltage or current to represent a signal. The origin of the term is that the electrical signal can be thought of as being ‘analogous’ to the original signal.

Question 23

Amplitude:

Answer 23

The actual level of a signal, usually measured in volts.

Question 24

Audio Rate:

Answer 24

Electronic signals in the audio range: nominally 20Hz to 20kHz.

Question 25

Cycle:

Answer 25

One complete vibration of a sound source or its electrical equivalent. One cycle per second is expressed as 1Hertz (Hz).

Question 26

Digital:

Answer 26

Electronic system which represents data and signals in the form of codes comprising 1s and 0s.

Question 27

Gate:

Answer 27

An electrical pulse that is generated whenever a key is depressed on an analogue synthesizer. This is used to trigger envelope generators and other events that need to be synchronized to key action.

Question 28

Polyphony:

Answer 28

The ability of an instrument to play two or more notes simultaneously. An instrument which can only play one note at a time is described as monophonic.

Question 29

Q(filter resonance):

Answer 29

A measure of the resonant properties of a filter. The higher the Q, the more resonant the filter and the narrower the range of frequencies that are allowed to pass. This will be explained in more detail when we talk about filters later in the series.

Question 30

Ring Modulator:

Answer 30

A device that accepts and processes two input signals in a particular way. The output signal does not contain any of the original input signal but instead comprises new frequencies based on the sum and difference of the input signals’ frequency components. Ring Modulators will be covered in depth later in the series. The best known application of Ring Modulation is the creation of Dalek voices but it may also be used to create dramatic instrumental textures. Depending on the relationships between the input signals, the results may either be musical or extremely dissonant — for example, ring modulation can be used to create bell‑like tones. (The term ‘Ring’ is used because the original circuit which produced the effect used a ring of diodes.)

Question 31

Sample and Hold:

Answer 31

An analog ‘memory’ circuit used to store the keyboard voltage when a key has been released. Without this, the note would change as soon as the key was released. Sample and Hold circuits may also be used to extract random voltages by sampling a noise waveform at regular intervals. This latter function was much used as a rhythmic device in the early days of synthesis; the random voltages could be used to control oscillator pitch, filter frequency, envelope level and so on. The applications of sample and hold circuits will be further explored later in the series.

Question 32

Subtractive Synthesis:

Answer 32

The process of creating a new sound by filtering and shaping a raw, harmonically complex waveform.

Question 33

Timbre:

Answer 33

The tonal ‘color’ of a sound.

Question 34

Tremolo:

Answer 34

Modulation of the amplitude of a sound using an LFO.

Question 35

Velocity:

Answer 35

The rate at which a key is depressed. This may be used to control loudness (to simulate the response of instruments such as pianos) or other parameters on later synthesizers.

Question 36

Vibrato:

Answer 36

Pitch modulation using an LFO to modulate a VCO.

Question 37

Waveform:

Answer 37

A graphic representation of the way in which a sound wave or electrical wave varies with time. (amplitude over time)