Preferred dimension ratios of small rectangular rooms.

Jens Holger Rindel

doi:10.1121/10.0003450

Abstract

Rooms for music rehearsal, sound studios, control rooms, etc., need a smooth frequency response. For that reason, the frequencies of the room modes should be spread as well as possible, and this is controlled by the aspect ratios of the dimensions. The relative variance of the frequency spreading of the lowest 25 room modes is applied as a quality criterion. The results have revealed that the length-width ratio is much more important than the width-height ratio. The length-width ratio should be within 1.15-1.45. The height can be chosen more freely without compromising the acoustical quality.

Highlights

Rooms used for music, speech. or acoustical measurements need to have good acoustical properties
The frequency distribution of the room modes is dictated by the room dimensions or, more precisely, by the aspect ratio between the dimensions
The influence of the aspect ratio of room dimensions on the frequency distribution of the room modes has been studied using the relative variance of the frequency intervals as a criterion for the acoustical quality

Summary

Introduction

Rooms used for music, speech. or acoustical measurements need to have good acoustical properties. Say up to 300 m3, it is a challenge that the density of room modes is sparse at low frequencies. It is important to design the rooms in such a way that the room modes at low frequencies are spread as well as possible. The low frequency range is here defined as 20–200 Hz. The frequency distribution of the room modes is dictated by the room dimensions or, more precisely, by the aspect ratio between the dimensions. Setting the lower limit of the frequency range to 20 Hz, the lowest mode will be below that frequency if the longest dimension exceeds 8.6 m. With the most common aspect ratios of the room, this longest dimension corresponds quite well with a volume around 300 m3

Results

Discussion

Conclusion