Uploaded by SynthSchool on 30.03.2010

Transcript:

this is a sine wave

a sine wave is the basic building block of sound

any sound can be constructed by combining several sine waves in

different frequencies

the sine wave gets its name from the sinusoid function which describes a

circle in two dimentions

since sound only exists on one dimension -

the time dimension, the graph cannot go back on itself to create a real

circle

so basically a sine wave is audio's circle

just as you can create a complete drawing from small dots

you can also create any sound conceivable by mixing together several

sine oscillators

let's listen to the sine oscillator

the graph you're looking at is an oscilloscope

the y_ axis represents the amplitude

this is the zero point this is

the maximum and this is the minimum

and the x-axis represents time

the y_ axis that's exactly as your speaker would

when the graph is on top

their speaker is pushed forward towards you

when it's down

the speaker is pulled away from you

when it's on zero the new speakers driver is centered on an ideal state

when i play high notes

more wave cycles are compressed into the view

this is because high frequencies are shorter an our graph has a set time

window

if we play low notes,we can see that there are less cycles in our view

this is because there are slower and they take more time to evolve let's

look at the sine in our frequency analyzer

as you can see the sine only has one peak

and has no frequency content on any sides of the spectrum

this is why a wine wave is often referred as a pure tone as it is the

only sound that consists of a single basic frequency

this basic frequency is called the fundamental frequency

if we look at other wave shapes such as the saw or square

now we're looking at a saw wave on an oscilloscope

if we look at the frequency analysis of the sound

we can see that it

has many spikes

those spikes are extra high frequencies that construct the sound's timber

these also called overtones

overtones construct each sound that we hear each day

overtones can be harmonic

or non harmonic

non harmonic overtones result in noise or sounds with ambiguous pitch

while harmonic overtones

support the fundamental frequency

and keep its tonality intact so as you can already guesse

we can make a saw oscillator out of many sine oscilltors

the lowest frequency of the sound is the basis

on which the sound is built and is called the fundamental frequency the

rest of the spikes here are called overtones

harmonic overtones will always be the fundamental frequency multiplied

by a whole number

let's take for example the note A 110hz

it as a fundamental frequency of one hundred and ten hertz

and its first harmonic is it's fundamental frequency

one hundred and ten hertz

its second harmonic would be

the frequency times two which means 220Hz

the third one will be 330Hz

times four

times five

and so on

the idea behind the system

is to keep our wave cycle repetitive and the only way to do that

is to have the overtones

start

and finish it at the same phase over the fundamental frequency

as you can see here and we have a green blue we have small sine waves here

that

represent the harmonics of the sound

the first harmonic would be the fundamental frequency the second

harmonic has two cycles per one cycle of the

fundamental frequency

and because of that it starts

and it's ends and the same point

and it's the same with the third harmonic which has three cycles per one

or here we have four cycles per one and it actually follow it it's pretty

accurate

and so on to infinity

let's listen to those harmonics

does it sound musically familiar

of course it does this is the building block of all music

it occurs naturally in nature

and it exists in all human music

personality for me it sounds like an indian flute indian flute or something like this

let's see how a saw is constructed from many sine oscillators by adding them

one by one

let's start with the fundamental frequency

and now we add the second harmonic

third harmonic, as you can see there are

three slides here

and its starting to resemble a saw shape

we are going to add this harmonic here

and i could go on forever but but my cpu does not have enough horse power

and sixteen is enough too demonstrate the idea

this saw wave has all of the harmonics but not all waves have to have all of the harmonics

for instance the square

does not have any even harmonics

it skips the two four six

and so on

of the harmonics adding only the odd harmonics

so, one is the odd harmonic

as you can see two,

we're not mixing inside

we're skipping it

str8 to twtree

and voilla it starts to look like a square

we skip the fourth harmonic,

fifth we add in

we skip the sixth

we add the seventh and so on...

let's look at the same thing on the frequency analyzer

here is a saw wave

this is our fundamental frequency and now we're going to add the overtones

let's look at our square wave

the first one

the second one we skip

third, fifth, seventhи

let's look at the relations between frequencies

i have selected to 220hz as my fundamental frequency

and my next overtone will be an octave higher,

the fundamental frequency times two

thats 440hz

the next overtone will be

a fifth higher than the second overtone

or and octave and a fifth higher than the fundamental

the fourth one will be two octaves higher than the fundamental

and a perfect fourth higher than the previous overtone

and as you can see, as i go up the overtones

the interval

with the previous overtones gets smaller and smaller and smaller

as i go up it reaches microtones

the recipe for making a classic saw oscillator is having heath overtone's

amplitude divided by its harmonic count.

so for instance

the first overtone would be on maximum volume

the second one

would be half the volume

third one, would be thirthd the volume you can see it here also

and so on

so theoretically a saw wave should have infinite overtones

that's it for this lesson i hope you got a little bit wiser if you want to

download this device and explore the world of harmonics, sound or generally learn

about synthesizers and how to make great sounds

just visit our website www.synthschool.com

a sine wave is the basic building block of sound

any sound can be constructed by combining several sine waves in

different frequencies

the sine wave gets its name from the sinusoid function which describes a

circle in two dimentions

since sound only exists on one dimension -

the time dimension, the graph cannot go back on itself to create a real

circle

so basically a sine wave is audio's circle

just as you can create a complete drawing from small dots

you can also create any sound conceivable by mixing together several

sine oscillators

let's listen to the sine oscillator

the graph you're looking at is an oscilloscope

the y_ axis represents the amplitude

this is the zero point this is

the maximum and this is the minimum

and the x-axis represents time

the y_ axis that's exactly as your speaker would

when the graph is on top

their speaker is pushed forward towards you

when it's down

the speaker is pulled away from you

when it's on zero the new speakers driver is centered on an ideal state

when i play high notes

more wave cycles are compressed into the view

this is because high frequencies are shorter an our graph has a set time

window

if we play low notes,we can see that there are less cycles in our view

this is because there are slower and they take more time to evolve let's

look at the sine in our frequency analyzer

as you can see the sine only has one peak

and has no frequency content on any sides of the spectrum

this is why a wine wave is often referred as a pure tone as it is the

only sound that consists of a single basic frequency

this basic frequency is called the fundamental frequency

if we look at other wave shapes such as the saw or square

now we're looking at a saw wave on an oscilloscope

if we look at the frequency analysis of the sound

we can see that it

has many spikes

those spikes are extra high frequencies that construct the sound's timber

these also called overtones

overtones construct each sound that we hear each day

overtones can be harmonic

or non harmonic

non harmonic overtones result in noise or sounds with ambiguous pitch

while harmonic overtones

support the fundamental frequency

and keep its tonality intact so as you can already guesse

we can make a saw oscillator out of many sine oscilltors

the lowest frequency of the sound is the basis

on which the sound is built and is called the fundamental frequency the

rest of the spikes here are called overtones

harmonic overtones will always be the fundamental frequency multiplied

by a whole number

let's take for example the note A 110hz

it as a fundamental frequency of one hundred and ten hertz

and its first harmonic is it's fundamental frequency

one hundred and ten hertz

its second harmonic would be

the frequency times two which means 220Hz

the third one will be 330Hz

times four

times five

and so on

the idea behind the system

is to keep our wave cycle repetitive and the only way to do that

is to have the overtones

start

and finish it at the same phase over the fundamental frequency

as you can see here and we have a green blue we have small sine waves here

that

represent the harmonics of the sound

the first harmonic would be the fundamental frequency the second

harmonic has two cycles per one cycle of the

fundamental frequency

and because of that it starts

and it's ends and the same point

and it's the same with the third harmonic which has three cycles per one

or here we have four cycles per one and it actually follow it it's pretty

accurate

and so on to infinity

let's listen to those harmonics

does it sound musically familiar

of course it does this is the building block of all music

it occurs naturally in nature

and it exists in all human music

personality for me it sounds like an indian flute indian flute or something like this

let's see how a saw is constructed from many sine oscillators by adding them

one by one

let's start with the fundamental frequency

and now we add the second harmonic

third harmonic, as you can see there are

three slides here

and its starting to resemble a saw shape

we are going to add this harmonic here

and i could go on forever but but my cpu does not have enough horse power

and sixteen is enough too demonstrate the idea

this saw wave has all of the harmonics but not all waves have to have all of the harmonics

for instance the square

does not have any even harmonics

it skips the two four six

and so on

of the harmonics adding only the odd harmonics

so, one is the odd harmonic

as you can see two,

we're not mixing inside

we're skipping it

str8 to twtree

and voilla it starts to look like a square

we skip the fourth harmonic,

fifth we add in

we skip the sixth

we add the seventh and so on...

let's look at the same thing on the frequency analyzer

here is a saw wave

this is our fundamental frequency and now we're going to add the overtones

let's look at our square wave

the first one

the second one we skip

third, fifth, seventhи

let's look at the relations between frequencies

i have selected to 220hz as my fundamental frequency

and my next overtone will be an octave higher,

the fundamental frequency times two

thats 440hz

the next overtone will be

a fifth higher than the second overtone

or and octave and a fifth higher than the fundamental

the fourth one will be two octaves higher than the fundamental

and a perfect fourth higher than the previous overtone

and as you can see, as i go up the overtones

the interval

with the previous overtones gets smaller and smaller and smaller

as i go up it reaches microtones

the recipe for making a classic saw oscillator is having heath overtone's

amplitude divided by its harmonic count.

so for instance

the first overtone would be on maximum volume

the second one

would be half the volume

third one, would be thirthd the volume you can see it here also

and so on

so theoretically a saw wave should have infinite overtones

that's it for this lesson i hope you got a little bit wiser if you want to

download this device and explore the world of harmonics, sound or generally learn

about synthesizers and how to make great sounds

just visit our website www.synthschool.com