Abstract

Nowadays impulse response (IR) measurements are an usual practice in room acoustics. And, for auralization purposes they provide the fundamental data. Many times, for acquiring representative impulse responses of the room it is necessary to excite it with an omni-directional sound source. Classical dodecahedrons can fulfil the directivity patterns and other necessary specifications like sound power. Despite of that, in term of anechoic time responses they can not represent the best solution. Some applications of IR like auralization involve some signal processing of the acquired data. An adequate clearness for the measured IR helps in the successive steps (IR analysis, audio editing, signal processing, etc.). Regarding to an ideal point source dodecahedron multiply by twelve the number of reflections between the sound source and the receivers inside an enclosure. This effect makes the achieved IRs not as clear as necessary. To tackle these limits the new sound source, called “Elli”, was designed especially for impulse response acquisition. Elli is made by only two coaxial loudspeakers plus a sub-woofer. This small number of transducers minimizes the radiating membranes and consequently, reduces the amount reflections inside the room in respect to twelve vibrating membranes. The configuration of the source system was optimized to achieve the omni-directional patterns required by the standard for acoustic measurements in performance spaces. The current paper shows some preliminary approaches to the final prototype, the main assemblage features, and the principal results for measurements of directivity and frequency response.