The ultimate judgement of a product is made by people, and so in developing new products a certain amount (or maybe even a considerable amount) of testing has to be done on subjects. This is known as jury testing. The idea is to play people the sounds of the different products and get them to evaluate the quality of the sounds. However, great care must be taken when undertaking these procedures, as it is very easy to lead the subjects into making the judgements you want to hear, rather than their true opinions.
It is possible to buy sound quality testing software and hardware from an instrument manufacturer such as Bruel and Kjaer, 01dB, Head Acoustics etc.. By doing this, you buy into well made and reliable testing software. You also get all the hardware that you need, such as properly calibrated transducers. However, the cost of these instruments may be prohibitive to some, so the idea here is to give guidelines for those who want to carry out jury testing without these instruments, or to give further explanation to the process for those who own those instruments.