Music Tech Away Day 2012

Jonathan P Wakefield

Overview of current research supervisions:• Mark Mynett – PhD p/t - Music Production for Contemporary Metal• Steve Fenton – PhD p/t - Objective Measurement of Sound Quality in Music

Production• Braham Hughes – PhD p/t - Development of a Tool to Assist in the Creation of

Effective Audio/Visual Environments in Film and TV post-production • Neil Fitzpatrick – PhD p/t - The Global Studio: An evaluation of emergent

technologies and practices relating to real-time online collaboration and production of popular music

• Ruth Taylor – EntD p/t - An Alternative Model for Enterprise in Higher Education • Chris Dewey - MRes p/t - A Visual Interface for Mixing Popular Music

Currently being examined:• Ben Evans - MRes p/t - The Evaluation and Optimisation of FFT and Multiresolution

FFT parameters for use in automatic music transcription algorithms

Interface for Mixing Popular Music

Jonathan P Wakefield

User interface for mixing (and recording) sound really hasn’t changed in 50 years

• Is it the best interface?• Does it provide all the information an

engineer needs?• Rather than the channel strip

approach can’t we provide views of the whole mix?

• We’re drawing on ideas from David Gibson (see left) but importantly trying to make a practical tool for engineers

• Current thinking is to flag up problems in mix to engineer for manual resolution but may move into automating of aspects of mixing

Ambisonic decoders for 5.1

Jonathan P Wakefield

Development of improved Ambisonic decoders for 5.1 surround sound playback

• Horizontal only Ambisonics (omni mic plus 2 figure of 8s)

• Can convert a mono source to Ambisonics B format:

Speaker feeds are then:

Ambisonic decoders for 5.1

Jonathan P Wakefield

• So we need to find values 15 for parameters for a working decoder

• Determined by having a multi-objective fitness function that is based Gerzon’s meta-theory of localisation which is based on:

• Velocity vectors • Energy vectors

• Vectors quantify low to mid and high frequency localisation performance

• A heuristic search algorithm is used to find parameter sets with good fitness values• We run multiple local searches to come up with a “good” parameter set

• We have also done two HPC implementations where we have ran exhaustive global searches at reduced parameter resolution

Ambisonic decoders for 5.1

Jonathan P Wakefield

Have developed decoders that :• Provide even performance around listener• Take account of Human Spatial

Resolution (MMA)• Optimise for multiple off centre listeners• Optimise for constrained listening spaces

(and simultaneously determine best speaker positions within constraints)

• Also developed a Design Tool• Used Range-Removal and Importance

concepts in fitness function• 1st Order, 2nd Order, 4th Order decoders

Ambisonic decoders for 5.1

Jonathan P Wakefield

• Currently doing listening tests to confirm validity of velocity and energy vectors in determining human perception of localisation

Future Work• Trying to find a way to convert discrete 5.1 mixes into Ambisonic

format ?!?!?!?• Extend to with height surround sound reproduction• Compensate for playback room acoustics

Loudspeaker Arrays

Jonathan P Wakefield

Planned experiments:Single line:

• Automatically take stereo and play across (say) 9 speakers instead of stereo pair

• Get multi-track and pan to 9 speakers and compare to stereo mix

• Get producers to mix to format and compare to stereo mix

Do same for 2-D spearker arrangement

Computer-based Musical Evolution

Jonathan P Wakefield

• Tim Milllea – Automated Composition of Popular Music

• Need to analyse existing good songs• Analysis feeds into a fitness function• Genetic Algorithms evolves a population

of solution guided by fitness function• GA needs a crossover function

(hierarchical)• GA also needs a mutation function

• With Dr Steven Jan• Replicating the evolution of music

(classical/folk)• Unsuccessful AHRC bid this year• Supervising a Visiting Researcher/

Academic for 12 months

• Also have a German Cognitive Sciences undergraduate coming for 3 months