In a communication system, audio quality is one of the parameters by which the end user defines the value of a product. This thesis examines the term audio quality, breaking it down into two subsidiary components, speech quality and speech intelligibility. One key goal in assessing audio quality is quantifying it in an accurate and repeatable way. As a part of this project a system was developed that achieved this goal. The system was then used to evaluate a number of existing products based on speech quality and intelligibility. Using these results the relationship between the two parameters was investigated. Investigations were also conducted in order to determine and quantify the effect communication systems have on perceptual speech parameters, and examine the relationship between them and speech quality and intelligibility. Using the testing systems developed a possible method of audio quality optimization was investigated and tested. The analysis methods that were incorporated into the test suite included the Perceptual Evaluation of Speech Quality, the Speech Transmission Index, vowel space analysis and segmental, psychoacoustic based methods. The testing incorporated a number of different handheld portable radios as speakers.