Music Technology

Musical Acoustics

What is Sound?

What is Sound?

Human Aspect of Sound?

Physical Aspect of Sound?

What is Sound?

Human Aspect of Sound?What is heard

Physical Aspect of Sound?Pressure disturbances propagating through a medium, usually air

What is Pitch?

What is Pitch?

Repetition rate in a Sound

Not the same as frequency – a note with given pitch normally contain many frequencies – what are these different frequencies called?

What is Frequency?

Repetition rate for a simple oscillator

An oscillator is a repetitive wave e.g. sine wave, saw wave etc.

What is Frequency measured in?

What is Frequency measured in?

Hertz

Normal hearing range is 30-15,000Hz

Frequencies

The range of pitch of the piano is 30-4,000Hz

The lowest notes are heard almost entirely via the harmonics present in the tone.

Harmonics

All oscillations contain more than one frequency. The cluster of all the different sounding frequencies make the tone of the sound.

The frequencies are often exact multiples of the lowest, fundamental frequency, or near to this.

Harmonics

What, therefore, does EQ do?

What, therefore, does EQ do?

• Boosts and cuts certain frequencies, which will inevitably, take out or increase the dynamic volume of some of the harmonics.

EQ Bands

Normally three bands:

High Freq: 5-6kHz upwardsMid-Range: 500Hz – 5kHzLow Freq: 50Hz-500Hz

Why should you use EQ?

Why should you use EQ?

• Enhances the balance of the overall sound, by altering the tonal qualities of individual instruments

• Makes MIDI sounds more realistic• Removes unwanted frequencies• Separates mid-range sounds that are similar in

frequency, helps to give clarity to the mix, and stops them blending too much on important parts

• Bring out important melodies

Types of EQ

Shelving EQ

Types of EQ

Shelving EQ:

High freq: Cut/boost all the signal above a certain frequencyLow freq: Cut/boost all the signal below a certain freq.

Can you draw it?

High-Shelf Boost

Low Shelf and High Shelf Cut

Band Pass EQ

Cut/boost the signal between an upper and lower frequency.

Band Pass EQ

Cut/boost the signal between an upper and lower frequency.

Sweep EQ

A band-pass EQ with the option of adjusting the centre frequency around which the signal is altered.

http://www.youtube.com/watch?v=Gmrve23xRW8

Parametric EQ

A sweep EQ with the option of adjusting the ‘Q’ (also called resonance). This increases or decreases the range over which the frequency is cut or boosted either side of the centre frequency (increases or decreases the bandwidth)

• Low Q Factor: wider bandwidth

• High Q Factor: narrower bandwidth

Why is this important?

Why is this important?

Important for ALL portfolio

Use music technology keywords in your logbook to explain your choice of EQ and why.

Making sounds more realistic and fitting Task 1A better.

Synthesis

What is Synthesis?

How have you currently been creating your sounds for your instruments?

Synthesis

How are sounds created?

Synthesis

How are sounds created?

An oscillator creates a sound wave which can then be manipulated to design the sound you wish

Oscillators

Used to generate a raw repeating signal/wave

Different tyes of oscillators produce a variety of signals including sine, triangle, sawtooth, square and random noise waves

Sine Wave

• http://en.wikipedia.org/wiki/Sine_wave• No harmonics

Triangle Wave

• http://en.wikipedia.org/wiki/Triangle_wave• Only odd harmonics are sounded

Harmonic Numbers

Square Wave

http://en.wikipedia.org/wiki/Square_waveOnly uses odd harmonics – sounds similar to a triangle wave but slightly brighter in treble

Sawtooth Waves

• http://en.wikipedia.org/wiki/Sawtooth_wave• Uses all harmonics – sounds quite gritty

Why are these important to you?

Why are these important to you?

You can design your own sounds – very important!!

Start with a template and then adjust it or start from scratch if you wish!

What is the Sound Envelope?

What is the Sound Envelope?

ASDR

AttackSustainDecayRelease

Alter the sound of the audio signal over time, from the time it starts until the time there is no sound.

Sound Envelope• What

about a piano?

Sound Envelope (ASDR)

• Example of a piano: • What about a trumpet?

Sound Envelope (ASDR)

How to design your sound using the sound envelope

http://en.wikiaudio.org/ADSR_envelope

Filters

What do filters do?

Filters

What do filters do?Modify a signal by cutting/removing a specific frequency band. Changes the brightness of a sound. Filters use a cut-off frequency to define which frequencies are removed from the signal

Two main types: high-pass and low-pass

Types of filters

Low pass filter – removes frequencies higher than the cut-off frequency, allowing the lower frequencies to pass throughHigh pass filter – removed frequencies lower than the cut-off frequency, allowing the higher frequencies to pass through. Band pass filter – uses combination of both HPF and LPF to allow only frequencies near the cut-off to pass throughBand-elimination filter – uses both LPF and HPF to remove only frequencies near the cut off.Peaking filter – emphasizes frequencies near the cut-off frequency – also called resonance.

Sound Design and Synthesis

Start with an oscillator and work on the sound you likeAdjust the envelope (ASDR)Use EQ and filter to boost/cut the correct harmoniesUse reverb to complete the sound

Write it all up in your logbook – so important to show you can design your own sounds!!