Papers

Here are some academic papers I wrote while studying for the Tonmeister course at the University of Surrey.

Line Arrays for Live Sound

Line array systems are now the forerunner in large scale live sound reinforcement. This report describes why they have become so accepted and widely-used over the last two decades, explores different arrangements of arrays and why these are necessary, the benefits they have over more traditional horizontally clustered systems in both directionality and high frequency throw and how these are achieved. It also illustrates practical advantages, disadvantages, cabinet design and techniques for setup, configuration and touring.

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Optimization of a FOH Sound Reinforcement System

When installing a front-of-house sound reinforcement system, there are many factors to be bore in mind to gain optimum technical performance. This paper goes some way to outlining important technical requirements of a large scale concert and describes several techniques commonly used for optimisation including positioning, time alignment and equalisation, focusing specifically on front-of-house sound, as opposed to that for monitor mixing.

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A subjective comparison of MPEG-4 AAC codecs

MPEG-4 AAC and other high quality compression codecs are gaining popularity among internet users, who have previously been using MPEG-1 Layer III (mp3), a standard and trusted audio format for internet distribution and computer storage. While MPEG codecs are defined standards, the implementation of the encoder is open to development, with many improvements being made to perceptual models and quality of encoder over recent years, some of which are better than others. A large amount of these codecs can be found on the internet, which is a potential cause of confusion to consumers.

This paper investigates the audio quality of four different MPEG-4 AAC codec implementations (namely Apple, Nero, Compaact! and FAAC) at average bit-rates of 128 and 160kbps, and which one produces the most transparent results. A MUSHRA listening test was run to test the different codecs, and this is mapped out in full, showing test methodology, results and conclusions.

A review is made of low bit-rate audio coding principles and techniques, why they can be successful with an overview of human auditory characteristics, and a closer look at the development of MPEG coding standards from MPEG-1 Layers I, II and III, through to MPEG-2 AAC and MPEG-4 AAC including the techniques utilised by these codecs and their inherent problems.

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