AES 東京コンベンション 2009
Paper Session A3

In designing a fine multichannel monitoring environment, `low frequency control' and `wide listening area with natural playback sounds' are the important keys. In this paper, three practical design strategies are introduced to realize these keys. The first strategy is a calculation technique of modal analysis using `modal summation method.' It can predict low frequency properties of a rectangular room with less modeling/computing load. The second strategy is an active reflection control. It is a technique to improve low frequency responses by adding reflection sounds. The third strategy is a DFR (Decorrelated First Reflections). It is a design method of time response using early reflections actively. These strategies are introduced through a real design project, multichannel mixing room of NHK's CP604 Studio. Both calculated and measured data for the project shows good responses to demonstrate usefulness of the design methods proposed here.

The loudspeaker setup was compliant with ITU-R BS775-1. Excellent architecture acoustics characteristic. HD520 employed cutting-edge system machine. HD520 was designed for the high quality works. I do presentation of HD520 about that acoustics characteristic and the system construction

A basic study on a multi-layered diffuser composed with different sized cylinders in random distribution for a diffused reflection mechanism in small rooms is examined. This paper shows the result of the study on the effect upon room acoustic characteristics, especially focused on the eigenmodes at low frequency, the characteristics of diffused reflection, and the sound absorption characteristics of the diffuser. The full and 1/5 scale model experiments and the simulation using the FDTD (Finite Difference method in Time Domain) are used for this investigation.

In acoustic design for small and medium-sized rooms, it is important to control low frequencies. But conventional evaluations methods are not suitable to make objective evaluation to find the only correct answer. In this study, a new evaluation method is proposed which has conventional mode density and effective mode density, represented by an index N, incorporated for mode evaluations. Use of the index N enables SPL deviation and degeneracy to be evaluated with simple numeric values. Moreover listening examination can be also carried out by auralization of room response.