Many virtual reality applications incorporate realistic room acoustic simulation to provide increased immersiveness and realism. Traditional geometric methods, although providing modeling accuracy, are usually impractical for use in interactive applications. At the same time, artificial reverberators, with feedback rendering structure, are widely used as a low-cost alternative. This paper presents the design of a geometric-based artificial reverberator inspired by the acoustic rendering equation (ARE) and the feedback delay networks (FDN). The simplified acoustic rendering equation, which models both specular and diffuse reflections, is incorporated with the FDN structure. Our reverberator, despite of modeling the diffuse and late reverberation, is also capable of simulating the early/specular reflections with accuracy. This novel work is among the very few works which are capable to simulate early reflections using feedback delay networks.