A Guide to Using Logic to Re-Create Audio Using Sequencing Software and to Demonstrate the Basic Principles of Sound and AcousticsThis E-book will give you a basic understanding of how to recreate audio using MIDI and sequencing software by using Logic Expresses many capabilities as well as demonstrating the basic principles of sound and acoustics. The computer you will be using is an Apple Mac Mini, used by many high end recording studios.You will also be using a MIDI Keyboard or a Musical Instrument Digital Interface keyboard, such as the Evolution MK-249z or the Korg Micro Key. MIDI is nothing more than data. MIDI contains a list ofeventsandmessagesthat tell an electronic device, e.g. a musical instrument, computer sound-card etc. how to generate a certain sound. With MIDI, there is no need to hire and record live musicians.You will also have two monitor speakers either side of your screen. These should only be switched on, via a switch on the back, once the computer itself is switched on.Monitor Speakers (Fostex)ScreenMIDI Keyboard Keyboard Mac Mini

Now you have your bearing of where the hardware you require is, it is time to begin.Once you have logged onto your Mac Mini, you see this screen (The Desktop)

To open logic click on the search icon in the top right hand corner of your screen. By clicking this icon, the Mac will allow you to search for software, documents, music and pictures that can be found on the hardrive. To find Logic, type Logic Express and click Logic Express.

By doing this, you will be brought to this screen.

At the bottom of your screen you will find your Transport Bar, from left to right, you will find: a Go To The Beginning icon, Play From Selection icon, Rewind and Forward icons, Stop Play and Pause icons and a Record icon. Moving to the right, you will find:Total TimeLeft LocatorBPMTime SignatureMIDI InSystem Performance

Playhead PositionRight LocatorProject EndDivisionMIDI Out

And finally you will find: Low Latency Mode, Cycle, Autopunch, Replace, Solo and Click or Metronome.

At the top of your screen, you will find this. Where you can find, from Left to Right, Inspector, Preferences, Settings, Auto Zoom, Automation, Flex, Set Locators, Repeat Section, Crop, Split by Playhead, Bounce Regions, Bounce, Colours, notes, Lists where you can find Event, Marker, Tempo, and Signature lists, and Media where you can browse Loops and Sounds.You will also find four drop down menus for Snap, Drag and cursor tools where you can choose from 14 different tool including, Pencil, Scissors, and Eraser.

On this screen, you will have the option from a drop down menu to choose from creating an Audio, Software Instrument or External Instrument track. The Two you need to be aware are Audio, used for recording or importing external audio, and Software instrument, used for MIDI. For the job of re-creating Audio using sequencing software, we shall mainly focus on Software Instrument tracks.To begin with, we must import the audio track we are attempting to re-create. To do this, select Audio in the New Tracks drop down menu and click Create.

Once you have clicked Create an Audio track will appear on your screen.

To import an Audio track into Logic, Click File, to the top left of your screen, click Import Audio File

This box will appear on your screen.For this Project, you will be re-creating Bronski Beats Smalltown BoyOnce you are Happy with your choice of audio, click it and then click open at the bottom right hand side of the box.

This will import the audio track into youre the audio track you made earlier.

The first thing to do when re-creating a track is to find the BPM or Beats Per Minute.To do this, Click on either of the boxes under the word, Inserts on the centre left hand side of your screen, click Metering > BPM Counter > StereoAnd this should appear on your screen. If you click play, the BPM Counter will begin to flash and will show a BPM after a couple of seconds.

Like so. This may change during the song, so pay attention and watch it for all of the song, for example, Smalltown Boy Changes from 126.1 to 134.3 gradually between bars 10 and 18.

You can edit the tempo by click the triangle next to Global tracks near the top left hand corner of your screen, and then click the triangle next to tempo. To change the tempo, click on the line and drag the point to your desired tempo.

Once you have found the BPM and corrected the tempo, you can begin re-creating the track.First you must make a Software Instrument Track by clicking the + symbol to the right of Global Tracks.When this menu drops down, you must click Software instrument and then Create.You can create more than one track at a time by typing in the number of tracks you desire in the box named Number.

I have Chosen to make five MIDI tracks because I can compare different sounds on different tracks to find the best sound that mateches the track.

By clicking on a track and then clicking on Media in the top right hand side of your screen, you can browse Logics library of sounds.

To input MIDI data, you can either, play it in in real time or draw it in manually.To play it in real time, click the Record icon on your transport bar and play the MIDI keyboard. If you wish to, you can click the Click/Metronome icon on your transport bar; this will play a tapping sound in time with the BPM and time signature.

Once you have played your MIDI data in, double click on the data and the piano roll will appear at the bottom of the screen. This can also be accessed by clicking Piano Roll near the bottom left of your screen.

Currently the data is not in time with the time signature.

By high lighting the data using your cursor and clicking the Quantizing drop down menu above the piano role and selecting an option, for 1 bar long chords, I recommend 1/16 Note then click the Q icon next to it.

Now all the chords are in time.

To create the closest fitting sound to the original, you will first need to understand the basic principles of sound and how it can be manipulated to match the original sound from a song.

The Basic Principles of Sound and AcousticsSound is an energy that travels periodically through a medium. Sound acts like a wave through the air, just like how water ripples when it is disturbed. Sound is omni-directional and moves away from the sound source with equal energy. A sound wave is a visual representation of an outwards pulsating bubble.

A sound wave propagates through the air which has molecules in it. When there is a disturbance of these molecules i.e. from a sound source, they collide through vibrations and oscillations or compression and rarefactionOne compression and one rarefaction is called a cycle. The number of these cycles per minute determines the frequency, measured in Hertz or Hz.1 Cycle per second = 1 Hertz/1Hz10 Cycles per second = 10 Hertz/10Hz10,000 Cycles per second = 10,000 Hertz/10,000 Hz or 10 kilohertz/10 kHzThe amplitude of the wave determines its volume.A humans frequency spectrum is 20Hz 20,000 Hz/20kHz but this diminishes over time.To process these compressions and rarefactions, we must look at The Ear. The sound wave vibrates the ear drum which is connected to three bones: the Hammer, Anvil and Stirrup which act as a lever, enhancing the sound whilst transferring the signal through the middle ear to the inner ear. The stirrup is attached to a thin tissue, the entrance to the fluid filled Cochlea. Hair cells within the cochlea transfer the sound information to the auditory nerve where it is then transferred to various brainstem and auditory cortex regions.

Musical note are set to frequencies, for example, concert pitch A is 440Hz, when played an octave higher, it is 880 Hz.

Each frequency has its own wavelength that can be found using the equation:

Where:V = Velocity/Speed of sound (344 m/s)F = Frequency (Hz) = Wave Length

For Example:The frequency of the note A4 is 440Hz.So to calculate its wavelength, we would:V = 344 m/sF = 440 Hz = ? = (0.782 m)

All instruments have different frequency ranges but some overlap so how can they be told apart?

Timbre is the character or quality of a musical sound or voice as distinct from its pitch and intensity. The timbre of a sound can vary from instrument to instrument, for example: A flute has a smooth and slightly Breathy sound because it is a smooth metal pipe which alters the pitch of the flautists breath over the mouth piece. The cello on the other hand has a very different timbre; its warm and hollow, due to its low register, the smooth hum of the strings played by a bow and its hollow, wooden body.

The shape of the instrument will affect its timbre, as well as the frequencies it produces, most notably the harmonics which make up the body of the sound.

Every sound wave has its fundamental frequency as well as its harmonics which make up the timbre of the sound.We can also differentiate between instruments using the Envelope. This is the shape of the sound.The envelope is a crucial part of a Waveform. The waveform is made up of: Attack, Decay, Sustain and Release or ADSR for short.Attack is the time taken for the sound to reach its highest amplitude.Decay is the amount of time taken between the sound reaching its highest amplitude and it reaching the sustain level.Sustain Is amplitude the sound will settle at if the note is held down.Release is the rate that the amplitude decays once a key has been released.

The ADSR of a sound can be altered on any synth on Logic. Although some instruments may only allow the user to change Attack and Release and not Decay or Sustain.

When using Cubase with a PC, only one synth uses ADSR whilst the others rely on other effects and automation to imitate it.

We can take all of this into account and think of sound as a physical phenomenon but for the brain to process it, we must look at sounds psychological effects.Psychoacoustics is the study of how the brain reacts and how it processes sound. The perception of sound is a very complex event and the system in which we handle the data has developed over thousands of years, primarily built with the need to survive and know what is happening around you. When we hear sound, it is processed in a number of different parts of our brains. The sound of a human voice is processed in a different way to the sound of an instrument, music doesnt lie, yet when you hear a voice, the brain immediately recognises truth or deceit, friend or foe, emotional state sound can also invoke past memories that have not been uncovered for many years.Psychoacoustics can be used when mixing and recording. Auditory Masking is the idea of different sounds interfering with other sounds such as noise pollution. If you were to be having a conversation at a bus stop and a bus drove past, the loud noise of the bus would over-power the noise of the conversation and you would momentarily stop hearing it, because the bus is louder. If a track in a recording is louder than another, the quieter of the two may appear significantly quieter than the louder of the two.

Equalisation (EQ)An Equaliser can be a device, circuit or piece of software that lets us to control various frequencies within the audible bandwidth.This allows us to: Correct specific problems in a recorded sound Overcome deficiency in frequency response Allow contrasting sounds from several instruments and recorded tracks to blend better in a mix Alter sound musically and creatively

The equaliser in Logic can be found on the left side of your screen labelled EQ and double clicking it.

This box will appear on your screen. By clicking on Analyzer the white line will show you what frequencies exist at that moment in time. To boost or reduce frequencies, click on the centre line wherever you wish to boost/reduce and move your cursor until you are satisfied.

Cubase also offers the ability to alter the EQ and has a larger database of pre-set EQs, but it doesnt not use Analyzer and relies on the users ear to reach the perfect sound.

Now using the synth and equaliser on Logic, you can manipulate the sound to match the original sound from the original track.