Sound Level Meters - The Past, Present and Future

摘要

Before the turn of the millennium, sound level metering equipment was still predominantly analogue but over the last 20 years developments in digital electronics have revolutionised the design and use of SLMs. In a 1992 Euronoise paper, when handheld devices were just beginning to embrace digital functionality for a few controls, storage or perhaps displays, the question was raised, "Where will it stop?" Clearly, cessation of any such developments is about as far from the case as it could be; device capability has grown to the point where not only have the number of measured acoustical parameters increased, but predominantly statistical computations and frequency and time weightings are all carried out in the digital domain. Component miniaturisation has evolved handheld units that are capable of more than rack-mounted machines could deliver 25 years ago. Interestingly, the initial-stage electro-acoustic analogue transduction technologies have not seen such dramatic changes; even now, although it may appear that we stand at the doorway of the next major leap forward with MEMS transducers and digitally-stored and interfaced data with TEDS microphones, there are still many challenges to be yet faced before such technologies can be embraced and incorporated. Nevertheless, not all changes have been improvements; battery life for one has taken a backward turn from earlier devices. This paper describes the development of the sound level meter over a period that fairly well equates with the IoA's own timeline, and also discusses the current challenges that we face now in driving further developments and possible challenges in the future."