The sound field generated from a cylindrical sonochemical cell is discussed in depth. This sound field is considered with a variable operating frequency. An acoustic model is developed to predict the spatial distribution of acoustic pressure, which is compared with experimental measurements of the spatial characteristics of luminescent emission from a cylindrical cell. A sound speed (averaged in space and time) within the cavitation environment in the range of 868-1063 in s(-1) was calculated. Under certain assumptions, this corresponds to a void fraction range of 2.9 x 10(-3) to 4.2 x 10(-3)%. The implications for electrochemical and chemical activity within cylindrical cells are discussed.