Introduction to Sound Theory and Computer Music

An introduction to Macs and Logic-The Mac the we use is the Mac Mini, it has:2.7GHz quad-core IntelA core i7 processor and16GB of memoryA 500GB/1TB hard driveA 256GB solid-state drive or a 1TB Fusion DriveIntel HD Graphics 4000 The computer also has:Four USB portsA FireWire 800 portA Thunderbolt portA HDMI portSDXC card slot

When using logic, it is important to turn the speakers on last and then turn them off last. This prevents the speakers from blowing.Whilst recording you should turn the speakers off so that you don’t get any feed back or background noise.Below is a diagram of a Midi room-

MIDI stands for Musical Instrument Digital Interface, instead of producing sound; the keyboard will send electronic signals to another device that will then produce the sound.The main part of the MIDI keyboard is the keys, they will be assigned notes depending on what channel has been selected in the music software being used. For example playing a C with the piano selected will just play the note C, however when a drum is selected, the keyboard will play the sound that has been assigned to that note. Some MIDI keyboards aren’t big enough to hold the same amount of keys as a normal piano. This is why they have a button to change the octaves. This means that the user can change the pitch of what they are playing instead of having to use their software to manually change the sound. This means it can act as multiple instruments. The keyboard will have inputs and outputs. The outputs will plug into the computer, which will allow any signals from the keyboard to be changed into sound. Inputs will let you plug in other instruments or microphones, these will be connected by either xlr or jack cables. The keyboard will transfer the electronic signals from the instrument or microphone to the computer.There are various toggles and buttons on a MIDI keyboard. There are volume levels for the output, inputs and the headphones, Also the pause play stop buttons. These make it easier to record as you would not have to go into the software and change the volume and start recording etc.

Once you have turned the mac on you will see the dock at the bottom of the screen and it should look like this:

The dock has multiple icons, which are applications, among them should be Logic, if you mouse over each one it will tell you what its called. If Logic is not there, press the Launchpad icon and it will be there, then if you want you can drag it onto the dock. When you click on logic it will give you options on what you want to start with. If you select empty project it will be a completely black track with no sounds set, so it will ask you what first track you want. The options will be: software instrument, Audio, Drummer, External MIDI or Guitar or bass.

For this project it is a good idea to have the song you are going to recreate on the track to use as a guide. So your going to want to click the audio option then press create in the bottom right corner.

When first starting a track it is a good idea to save straight away, you can do this by pressing 'File' the selecting 'Save as’, then you have to decide where to put it, either on a USB, a folder or simply on desktop. you can create a folder to put it in if you want. Doing this means you can just press save each time and if anything goes wrong with the mac, you’ll have some work saved

Now your going to want to put the song onto logic. You can do this in two ways, either press ‘File’ go to ‘Import’ then click ‘Audio File…’ then select the song that way

Or you can simply find the song in a folder or ITunes then drag and drop it onto the Audio track in logic.Once it’s in, it should look something like this.

Now you going to need to find the songs BPM and change your projects BPM to match this.Now you should see something like this on the left side of your screen.

You are going to want to select ‘Audio FX’ go down to ‘Metering’ then select ‘BPM counter’ then press ‘Stereo’.A small window should pop up and it should look like this:

Now before you use the BPM counter, you need to know about the Transport bar.

The Transport bar is where the Pause, play, record, stop, fast-forward and rewind buttons are. The pause play and stop button are all bound to the Spacebar Key on your keyboard which is a helpful shortcut. In the darker section you will see the current bar is, the BPM and the time signature.These are what you are going to need to change later on.

To now work the BPM counter all you need to do is play the song and it will automatically tell you its BPM in the window.

Now that you know the songs BPM all you have to do is go to the Transport bar and change the BPM to match the song.

Now is probably a good time to save, you can go to ‘file’ and press ‘save’ or you can simply press ‘cmd’ and ‘s’ at the same time on your keyboard

Starting out

The main page of logic is called the arrange page, this is where you will be able to access all the other areas of logic from.

Now you have the song in your project and you have corrected the BPM you can start to recreate the song. You need to make some Software Instrument tracks.To do this you need to press the + symbol above your Audio track.

This time, instead of pressing ‘Audio’ you will press ‘Software Instruments’ then at the bottom of the box is an option which is ‘number of tracks’. I prefer to just add one at a time so not to get confused however you may prefer to add multiple tracks.

One of the tracks you’ve added will automatically be assigned an instrument, which will always be a piano, however if you added multiple tracks the others will be nothing.

To change the song of a track you will need to press the library button in the top left corner.

Then this will pop out bellow

You can browse around in the library to find the instrument, then simply click on the instrument to assign it to the track you have selected.

Once you have selected a sound, you may want to check if your metronome is on, this will help you keep in time whilst recording, you can edit the metranome if you want to change its voloume and key etc.

Now you should be ready to record, just press the record button on the transport bar and play the keyboard, when you’ve finished just press the stop button.

If you are unhappy with what you have done you can record it again by deleting what you’ve done and recording it again, or you can edit it and make it better and keep it in time manually.To do this, double click on the box that has appeared as you were recording it or press ‘P’ and this should pop up.

This is called the ‘Piano Roll’ and it will show you the notes you have played with the bars at the top of the screen.To automatically put the notes in time select all of the notes or press ‘cmd’ and ‘A’ at the same time, then press ‘Q’ and it will quantize it.This can be useful but sometimes you may have to do it manually but dragging the note, you can also move it up and down to change the note.You will need tools to be able to edit the velocity, cut noted, glue them together ect. To get them you have to press the mouse symbol and this should appear.

Each tool has a different function and most of them are self-explanatory.The ‘Pointer Tool’ – lets you select things and is basically a mouse.

The ‘Pencil Tool’ – allows you to draw in notes and boxes.

The ‘Eraser Tool’ – will delete what you click on.

The ‘Finger Tool’ – lets you change the length of a note.

The ‘Scissors Tool’ – will cut the note or box wherever you click. For example if you click the middle of a note it will be in half and will now be 2 separate notes.

The ‘Glue Tool’ – will put 2 notes selected notes together.

The ‘Mute Tool’ – allows you to mute an individual note or box.

The ‘Quantize Tool’ – will put the selected note in time.

The ‘Velocity Tool’ – allows you to change how soft or hard a note is by dragging the note up or down.

The ‘Zoom Tool’ – will zoom in on what ever you drag a box over.

The tools are probably one of the most useful parts of logic, you can create an entire song just using tools.

You can repeat a recording by hovering over the top right corner of the box, you should see a little circle repeat symbol, and drag it to the length you want. And it should look like this.

You can also Cut, Copy and Paste just like you were on word for example. Cut will allow you to delete it then paste it again somewhere else, Copy will do the same as cut however it doesn’t delete it, and paste puts down what you’ve cut or copied.

Sound waves

Sound waves are what we hear, most humans will hear from 20Hz to 20,000Hz, however as you get older this range will become a lot less.An imported audio track on logic looks like this

Sound is the movement of molecules, usually we hear sound through vibrations in the air, but sound can go through objects like walls etc.These sound waves are a representation of what sound looks like.

When pitching forks vibrate they produce periods of high and low, known as compression and rarefaction of air molecules, and this produces a frequency.

A Rarefaction is a region in a longitudinal wave where the particles are furthest apart, however a Compression is a region in a longitudinal wave where the particles are closest together.

The speed of sound changes depending on what it is passing through. Normally when sound passing through air, it is 340m/s, however through water it is about 1497m/s and iron is Iron it's 5850m/s.

The diagram below is a wave length.

The size of a wavelength will determine how low or high the frequency is, if it has a very short wavelength it is a high pitch sound and if it has a short one it is a low pitch sound. Higher frequencies are more easily absorbed than low ones.

These are some example of wavelengths. Imagine wavelengths are like guitar strings, the lower pitch string (top string) when plucked will look like the bottom wavelength, it will be very streched out, however the higher pitched string (bottom string) will look more along the lines of the top one, it will be faster moving and more compact.

Listening back

Our ears allow us to hear sound, they do this by converting vibrations into sound.

The vibrations in the air will be funneled into our ears by the Pinna, travel down the ear canal and then vibrate the eardrum. Then a signal will be sent to the brain, which will convert it into the sound we hear.All sound that we perceive is psychoacoustic. As soon as sound passes through the ears, it stops being physical phenomena and becomes a matter of perception. What we hear is almost by rule different from what is actually sounding, due to the peculiarities and limitations of our hearing. And what we hear can largely differ from what we think we are listening to; due to the many tricks that perception plays on our awareness.Loud Noises can be harmful to your ears and can damage tympanic membrane, this can result in complete loss of hearing which is extremely painful, it also cannot be fixed, once you’ve damaged your ear extensively, you will be unable to repair it. This is why it is important to not have your headphones on full all the time, and to generally avoid being around loud noises for a long period of time like a festival without earplugs or some rest, id also recommend not having a air horn set of next to your ear.