Introduction

The music / sound design / computer / film industry is so full of…jargon…someone had to translate all the terminology into Plain English. Since we are fluent in this language at Bob & Barn, we felt the responsibility fell on us. Impress your dinner party companions, as a result, with your knowledge of adaptive differentials and pitch bending. (Just a suggestion.)

5.1

Term used to describe a multi-channel speaker setup / environment used primarily for cinema sound but is slowly seeping into consumer home cinema setups. The ‘5’ refers to the 5 main speakers – 1 each for left, centre, right, left surround and right surround. These all need to be placed in the correct orientation in the sound field to give the desired effect. The ‘.1’ refers to the sub-woofer. This is where all the lower frequencies of any given soundtrack are piped. There is no need to place it anywhere specifically in the sound field as it is difficult for the ear to identify the direction and the location of low frequency sounds. The most common format is Dolby Digital; other formats are DTS and Sony’s SDDS.

ADC / DAC - Analogue to Digital Converter / Digital to Analogue Converter

Converts audio sound pressure waves (any form of analogue sound) to discreet digital information (binary 1’s and 0’s) and vice versa. The quality of these converters can vary enormously from ‘consumer’ home CD-Players costing hundreds to hi-end professional digital equipment costing thousands and tens of thousands.

(Tech Bit) The benchmark for these converters are based on what’s called the Signal to Noise Ratio (SNR). It’s measured in Decibels, a logarithmic scale from 0 to 120 DB (0 being absolute silence and 120 being the threshold of pain – a plane taking off next to you!). The higher the value is to 120, the better the converters will be. There are other issues to take into consideration, but it’s a good starting point.

ADPCM - Adaptive Differential (or Delta) Pulse Code Modulation

A form of audio file compression that roughly equates to 3.5:1 file size by converting a 16-bit file to 4-bit (and some clever maths!) It was initially adopted by Nintendo as the hardware audio compression (called Bit Rate Reduction) on the Super Nintendo game console in the early 90s but it’s biggest boost came with Sony adopting the standard for Playstation audio and Microsoft supplying it as standard with Windows 95. It is now used on the phone exchanges, Nintendo GameCube, Microsoft X-Box and Sony’s Minidisc.

The reason behind its popularity is due to the small amount of CPU overhead required to decode the signal and relatively low perceptual loss in audio quality. (Mp3, although a lot better compressor, requires a significant amount of processing power to decode).

AIFF - Audio Interchange File Format

This is the standard file format for audio on Apple Macs. Similarly to Windows, files can support different sample rates and compression codecs (see codec definition.) Unlike WAV files, AIFF files only support mono or stereo.

(Tech Bit) Files are coded Little Endian / Big Endian on a Mac and vice versa on a PC for a WAV. Most PC / MAC audio programs will now be able to open (and may even save) files in both format to give cross platform compatibility.

API - Application Programming Interface

Essentially, this is a computer program / self-contained module written to control something specific. We use it to describe an audio API - a program that runs alongside the main game controlling all of the audio in real-time allowing the programmer to manipulate sounds on the fly. An example of this is to make a wind sample more blustery the higher up the player goes.

AU

This is the audio format for Sun Unix workstations. Can support 8-32 bit samples in mono or stereo. Native compression is U-Law.

CODEC - Compression-Decompression

A codec is an algorithm that compresses or decompresses audio / video. ADPCM and MP3 both require specific codecs. For compatibility purposes, if you wish to create a file that can be decompressed on any PC or MAC, make sure that is one that is installed by default.

CUE

A film and TV term used to describe a piece of music of any length written to accompany moving picture.

EQ - Equalisation

Everyone is familiar with the bass and treble controls on an amp or stereo, this is the most basic form of EQ. Mixing Consoles and other Pro-Audio equipment just take this to the nth degree by assigning complete control over the entire frequency range (20 – 20,000 Hz). An EQ is just another name for a filter.

(Tech Bit) This is done normally with 2 shelving EQ’s which control the low and high frequencies (e.g. 80 Hz and 12,000 Hz) and 1-3 peaking EQ’s in the middle ranges which allow you to specify which frequencies you would like to control and how much you add or subtract to them. The ‘Q’ setting (if you have one) will control the width of that frequency response – (how much you want that setting to control frequencies either side).

FILTERING

A filter can be viewed as a “sieve” on sound! It is simply a device (whether it be in software or hardware) that alters the frequency range of a sound. A low pass filter will only let the lower frequencies through and cut off any frequencies over a given value making it sound muffled. A high-pass filter is the reverse. You can filter things over time very smoothly to use as a musical effect.

A good example is listening to someone walking towards you whilst you are behind a heavy closed door. You can hear the footsteps coming, but only the lower frequency components. Once you open the door, you can hear it with far greater clarity because the door isn’t obstructing the sound and absorbing the hi-frequencies.

FMV - Full Motion video

Term coined by the video Games industry to describe the fancy pre-rendered animations normally seen in-between levels to help develop the story line. Because they are effectively linear animations streamed from the main storage device (be it hard drive or CD/DVD) they don’t suffer from the same limitations that in-game graphics do. Therefore they can be as lavish and over the top as the technology used to create them will allow. They can be thought of as short films.

FOLEY

Foley is the name given to the techniques employed for creating synchronous effects or live effects, named after Jack Foley, a sound editor at Universal Studios.

Foley-ing is an excellent means of supplying the subtle sounds that production mikes often miss. The rustling of clothing and the squeak of a saddle when a rider mounts his horse give a scene a touch of realism that is difficult to provide using other effects methods. A steamy sex scene in a film was probably, in reality, created by a Foley artist making passionate love to his / her own wrist.

(From filmsound.org’s definition of Foley – see http://www.filmsound.org/terminology/foley.htm)

FTP - File Transfer Protocol

The pre-cursor to HTTP (which is the programming protocol that allows us to view web pages) FTP was the first standard by which files were transmitted over the Internet and as such, is very robust and powerful. You can view public FTP sites anonymously using standard web browsers, or log onto a private FTP site using a username and password. This connection, when initiated can be seen as a secure way to transmit large files either way over the Internet. We recommend CuteFTP for the PC and Fetch for the Mac.

INSTRUMENTATION

This is the choice of which instrument you choose to perform certain musical functions i.e. which instrument should carry the melody, is the instrument capable of playing the notes in the desired range, and is it realistic to expect a trumpet player to mimic some of the complicated lines often played by the violin?

MIDI - musical Instrument Digital Interface

MIDI is the protocol by which synthesizers, samplers and other electronic musical instruments communicate with each other. Audio itself is not transmitted, just the data to instruct the Midi device as to which notes to play, on which sound, how loudly and for how long (in a nutshell!) Midi is a serial interface capable of transmitting up to 500 notes per second down a standard 5-pin din cable. Midi devices normally have 3 inputs, a Midi In, Midi Out and Midi thru (which is a direct copy of what comes into the Midi in to allow you to daisy chain it to other devices). Each cable can support up to 16 unique Midi channels – the theory being that you would use 1 channel for each device.

MP3

The most popular compression format for delivery of hi-quality music over the Internet (a medium requiring small file sizes.) It offers very high compression ratios (10:1 or higher are quite typical) and very low perceivable loss in quality of sound. For example, 1 minute of stereo CD quality audio will have a file size of around 10 MB. The equivalent MP3 file of a similar quality would be only 1MB in size.

A common misconception is that it means Mpeg 3. It actually refers to Mpeg 1 (the video format – precursor of Mpeg2 used in DVDs) layer 3 audio (3rd generation of Mpeg 1 audio).

(Tech bit) The compression scheme is based on the algorithm that sounds can be decomposed into additive sine waves (using the FFT - Fast Fourier Transform). Once the signal is represented in the frequency domain, various tricks (huffman coding, small blocks, etc) are used to compress the frequency data and make the file small.

OFFSET

An offset in programming terms is simply a number added or subtracted to a fixed number to give a different result. In game audio terms you could have a random volume or pitch offset. This is where the programmer attempts to imbue a sense of real life into a sample by either making it randomly louder or quieter, or higher or lower in pitch than simply repeating it time and time again at the same pitch or volume. The important factor is that this will only happen within a given range so using an offset can be viewed as a neat way of adding randomness in a controlled manner.

A footstep is a good example. If you assign a volume and pitch between 0 and 127 for each sample, set the base value to 64 for each, but add an offset or +/- 10, then each time you hear a footstep sound, it will playback at a volume or pitch of between 54 & 74.

OUTBOARD EFFECTS GEAR

A recording studio term used to describe the use of different external hardware devices to alter a sound. Whether that is by adding an effect to the sound (a reverb or delay) or modifying the existing sound (an EQ, filter or compressor).

PCM

Pulse Code Modulation.

This is the most common method for digitisation – the transfer from analog to digital sound. Each pulse measures a difference in modulation between that and the previous sample. The modulation here is a difference in amplitude. (See sampling). Most commonly used in reference to uncompressed digital audio.

PITCH BEND

Pitch bend is the gradual and smooth manipulation of pitch over time. A guitarist going from one note to another has the choice of either simply jumping to the 2nd note (which would be deemed a pitch shift), or gradually bending the string so that the pitch smoothly moves from the 1st note to the 2nd. This is pitch bend.

SAMPLING

Sampling is an accurate word to describe the process of converting audio from an analogue source into the digital domain. (E.g. recording from vinyl records onto your computer hard drive). A simple description is that it measures snapshots of volume over time. A CD player takes 44,100 different snapshots of amplitude (measure of loudness) and turns each sound level into a number.

(Tech bit) A CD player works in 16-bits. This gives you 216 different volume levels to work from (65536 – in computer speak although it’s actually –32767 to +32768). For every minute of recorded stereo sound, a PCM stream will take up approximately 10 MB of space on your hard drive.

SD2 - Sound Designer II

This is the native file format of Protools. Protools is the industry standard digital audio workstation. It runs exclusively on Apple Macs.

(Tech Bit) The format itself is essentially a RAW file with the description of type and creator held in the Macintosh resource fork (a small file that provides a MAC computer with information about the file with which it is associated). It can be either mono or stereo.

SEPARATION

Separation is the ability through careful and skilful mixing to hear all of the component parts of a piece of music. In busy orchestral music it is often possible to be unable to hear an important accompaniment because another element of the music is obstructing it.

SOURCE music

Just to clarify this, source music does not mean reference music – i.e. music that is used for simply reference purposes to aid the composer in his task of composing original music. Source music is the music that plays out during a scene (whether it be in a film, TV show or game is irrelevant) that is not written to accompany the scene, it’s just playing in the background – something on the radio, a band playing in a park etc.

SURROUND

Generic term used to describe sound that literally surrounds you. This normally involves having speakers placed around the room at key places so that the sound can be projected from anywhere in a 360 degree sound field. Analogue based surround such as Dolby Prologic and more recently Prologic II have made way for digital formats such as Dolby Digital, DTS & Sony SDDS where the same limitations as the analogue systems do not apply.

(Tech Bit.) Analogue systems use clever phase technology to push the sound from a conventional 2 channel stereo cable into 4 channels. Unfortunately on stereo systems this can make the sound feel slightly muffled, but also you have a reduction in frequency response in the rear speakers (which are mono). With digital systems, you do not have those restrictions. So not only do you have 5 discrete full frequency audio channels but also room for a sub.

VIBRATO

Vibrato is a musical term to describe small but fast pitch variations over time. Take the example of a vocalist singing a long continuous ‘aaahhh’. Over time, it is common for vocalists to add a bit of ‘warble’ to the note to add polish to a performance. That’s vibrato.

VOICINGS

This is how you decide which note of the chord to give to which instrument playing the chord. Sounds easy, but your decision can drastically alter the impact and sound of each chord and they have to be chosen carefully.

WAV - Windows Wave

The standard file format for audio on Microsoft Windows based PCs. Just to confuse the issue, files can have different sample rates or compression (ADPCM, MP3 etc.) and still retain the same ‘.wav’ extension. The format allows for mono, stereo or multi-channel audio in a single file (only a few programs support the latter).

XA

Another compressed audio format providing audio file size reduction in a ratio of around 3.5:1. It was originally a component of the CD-ROM eXtended Architecture standard developed by Philips and Microsoft in the late 80s for video playback.

(Tech Bit) This is whereby the CD-ROM device would read a file from the disc that is split into 8 equal sized interleaved streams, 7 of which are devoted to the video component, and 1 to the audio (a 37.8k 16-bit stereo file compressed using ADPCM). Various game audio people realised that the potential for this was far greater if you could use all 8 sectors for audio. This would maximise the amount of audio that we could get on a single CD. The loss in frequency response going from 44.1k to 37.8k was negligible so most felt it was worth it.