The University of Southampton
University of Southampton Institutional Repository

Reverberation enhancement for small rooms

Reverberation enhancement for small rooms
Reverberation enhancement for small rooms
Reverberation enhancement is a technology which allows the reverberation time of a room to be increased through the use of an electronic system. These systems have traditionally been applied to improve the acoustics of large concert halls but the technology can also be used in smaller spaces with several possible applications. Previous uses of reverberation enhancement in small rooms have largely consisted of direct transplants of systems designed for large concert halls. This work investigates the complications which arise when using reverberation enhancement in a small room due to the differences in the acoustic properties of the space and also the restriction on the channel count of the system due to physical constraints.

The first part of this work deals with increasing the resultant reverberation time of the room without requiring additional system channels. This is achieved through the use of processing within the system. Two methods have been investigated. The first extends the resultant reverberation time without changing the feedback gain. The processing used for this purpose is either electronic reverberation or simple delay, both of which have been shown to allow significant increases in resultant reverberation time. These changes can be predicted accurately using diffuse field theory. The other method uses time-varying processing to increase the maximum stable feedback gain. This has been shown to allow increases in resultant reverberation time but also causes undesirable artefacts which limit the usability of this technique.

The second part of this work focuses on the differences in the acoustic properties of small rooms and especially the ways in which these rooms differ from a diffuse field. This includes the consideration of the modal properties of the room at low frequency which are insignificant in a large room. It has been shown that the spatial and frequency variations of the room at low frequency can be reduced through numerical optimisation of the processing within the reverberation enhancement system. Finally, the diffusion of the sound field and the early energy in the impulse response have been considered. It is shown that restrictions on the resultant reverberation time may be required in order to create a subjectively acceptable acoustic response. Overall, this work has shown that by accounting for the properties of the room, excellent performance of the system can be achieved.
Hopper, Hugh
589e03e0-afbc-4ac8-97ac-cdbfd03ea207
Hopper, Hugh
589e03e0-afbc-4ac8-97ac-cdbfd03ea207
Thompson, David
bca37fd3-d692-4779-b663-5916b01edae5

(2012) Reverberation enhancement for small rooms. University of Southampton, Faculty of Engineering and the Environment, Doctoral Thesis, 174pp.

Record type: Thesis (Doctoral)

Abstract

Reverberation enhancement is a technology which allows the reverberation time of a room to be increased through the use of an electronic system. These systems have traditionally been applied to improve the acoustics of large concert halls but the technology can also be used in smaller spaces with several possible applications. Previous uses of reverberation enhancement in small rooms have largely consisted of direct transplants of systems designed for large concert halls. This work investigates the complications which arise when using reverberation enhancement in a small room due to the differences in the acoustic properties of the space and also the restriction on the channel count of the system due to physical constraints.

The first part of this work deals with increasing the resultant reverberation time of the room without requiring additional system channels. This is achieved through the use of processing within the system. Two methods have been investigated. The first extends the resultant reverberation time without changing the feedback gain. The processing used for this purpose is either electronic reverberation or simple delay, both of which have been shown to allow significant increases in resultant reverberation time. These changes can be predicted accurately using diffuse field theory. The other method uses time-varying processing to increase the maximum stable feedback gain. This has been shown to allow increases in resultant reverberation time but also causes undesirable artefacts which limit the usability of this technique.

The second part of this work focuses on the differences in the acoustic properties of small rooms and especially the ways in which these rooms differ from a diffuse field. This includes the consideration of the modal properties of the room at low frequency which are insignificant in a large room. It has been shown that the spatial and frequency variations of the room at low frequency can be reduced through numerical optimisation of the processing within the reverberation enhancement system. Finally, the diffusion of the sound field and the early energy in the impulse response have been considered. It is shown that restrictions on the resultant reverberation time may be required in order to create a subjectively acceptable acoustic response. Overall, this work has shown that by accounting for the properties of the room, excellent performance of the system can be achieved.

PDF
HAHopper_Thesis.pdf - Other
Download (2MB)

More information

Published date: January 2012
Organisations: University of Southampton, Inst. Sound & Vibration Research

Identifiers

Local EPrints ID: 348944
URI: http://eprints.soton.ac.uk/id/eprint/348944
PURE UUID: 115b7f18-db89-47df-821a-869458c33ab2
ORCID for David Thompson: ORCID iD orcid.org/0000-0002-7964-5906

Catalogue record

Date deposited: 06 Mar 2013 14:02
Last modified: 06 Jun 2018 13:02

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×