What is Sound? Part II Timbre & Noise

Prayouandi (2010) - OneOhtrix Point Never 1 PSYCHOACOUSTICS ACOUSTICS

LOUDNESS AMPLITUDE

PITCH FREQUENCY

QUALITY TIMBRE

2 Timbre / Quality

everything that is not frequency / pitch or amplitude / loudness

envelope - the attack, sustain, and decay portions of a sound

spectra - the aggregate of simple waveforms (partials) that make up the frequency space of a sound.

noise - the inharmonic and unpredictable fuctuations in the sound / signal

3 envelope

4 envelope

ADSR

5 6 Frequency Spectrum

7 Spectral Analysis

8 Additive Synthesis

9 Organ Harmonics

10 Spectral Analysis

11 Cancellation and Reinforcement In-phase, out-of-phase and composite wave forms

12 (max patch) Tone as the sum of partials

13 harmonic / overtone series

the fundamental is the lowest partial - perceived pitch

A harmonic partial conforms to the overtone series which are whole number multiples of the fundamental frequency(f)

(f)1, (f)2, (f)3, (f)4, etc.

if f=110

110, 220, 330, 440

doubling = 1 octave

An inharmonic partial is outside of the overtone series, it does not have a whole number multiple relationship with the fundamental.

14 15 16 Basic Waveforms

fundamental only, no additional harmonics

odd partials only (1,3,5,7...)

1 / p2 (3rd partial has 1/9 the energy of the fundamental)

all partials 1 / p (3rd partial has 1/3 the energy of the fundamental)

only odd-numbered partials 1 / p (3rd partial has 1/3 the energy of the fundamental)

17 (max patch) Spectrogram (snapshot)

18 Identifying Different Instruments

19 audio sonogram of 2 bird trills

20 Spear (software)

audio surgery?

isolate partials within a complex sound

21 the physics of noise

Random additions to a signal

By fltering white noise, we get different types (colors) of noise, parallels to visible light White Noise

White noise is a random noise that contains an equal amount of energy in all frequency bands.

White light is made up of all light frequencies (colours), while white noise is made up of all audio frequencies.

White noise is used in electronic music, either directly as a sound effect or as the basis to create synthesized sounds.

White noise is also used to mask other sounds — the brain is able to single out simple frequency ranges but has trouble when too many frequencies are heard at once. When white noise is present, other noises appear diminished. Pink Noise

Pink noise is a random signal, fltered to have equal energy per octave. In order to keep the energy constant over octaves, the spectral density needs to decrease as the frequency (f) increases.

This explains why pink noise is sometimes referred as "1/f noise." In terms of decibels, this decrease corresponds to 3 dB per octave.

The name of the color comes from visible light that turns pink when a similar spectral distribution is applied. Brown (Red) Noise

Brown noise is a random signal that has been fltered in order to generate a lot of energy at low frequencies.

The "brown" name comes from the "brownian" movement, not the color. Brownian noise is also referred to as red noise. Visible light turns red when a similar spectral distribution is applied.

Brown noise is obtained by running the same flter on pink noise, as the one used to turn white noise into pink noise. Brown noise offers the same bias toward the lower frequencies, as white noise does toward the higher frequencies. Grey Noise

Although white noise plays equally loudly at all frequencies, because of psychoacoustic properties, it fails in giving the listener a balanced perception.

White noise can be passed through a flter, which inverts our frequency sensitivity curves (Fletcher- Munson Curves), to create grey noise, a noise that feels perceptually fat.

Grey noise and white noise would be the same if our ears were equally sensitive to all frequencies in the audible spectrum. Tristan Perich - Microtonal Wall