HULTI-GEN (Huddersfield Universal Listening Test Interface Generator)
HULTI-GEN takes user-defined parameters (e.g. the type of scale, the number of trials and stimuli, randomisation, settings for reference and anchors, etc.) and automatically constructs a GUI suitable for the requirement of the listening test. This allows the user to quickly create various types of multiple and pair-wise comparison test environments. To assist the user, HULTI-GEN also provides a number of presets based on ITU-R recommended methods such as MUSHRA and ABC/HR. The user can also flexibly edit these presets to adjust the recommended methods for different test requirements (e.g., adding audible anchors, removing hidden reference, etc.). Subject's responses are saved as a text file, which can be easily imported into Excel for data analysis. HULTI-GEN supports the playback of multichannel wav. file of up to 28 channels, which is useful for multichannel 3D sound quality evaluations.
IAR is a VST Plugin for 3D audio production. Developed by Leo McCormack and Hyunkook Lee at APL, the current version of IAR offers 3D panning (VBAP and DBAP) over 9.1 3D loudspeaker setup and the headphone externalisation of the loudspeaker signals. It also provides an innovative novel 3D GUI with multiple points of view.
MARRS (Microphone Array Recording and Reproduction Simulator)
Developed based on a novel psychoacoustic time-level trade-off algorithm, MARRS provides an interactive, object-based workflow and graphical user interface for localisation prediction and microphone array configuration. It allows the user to predict the perceived positions of multiple sound sources for a given microphone configuration. The tool can also automatically configure suitable microphone arrays for the user’s desired spatial scene in reproduction. Furthermore, MARRS overcomes some of the limitations of existing microphone array simulation tools by taking into account microphone height and vertical orientations as well as the target loudspeaker base angle. The iOS and Android app versions of MARRS can be freely downloaded from the links below.
MAIR (Microphone Array Impulse Responses) Library and Renderer
MAIR is an open-access library of an extensive set of room impulse responses (RIRs) captured using numerous microphone arrays from 2-channel stereo to 9-channel surround with height. The RIRs were obtained for 13 loudspeakers placed in various positions on a stage in a reverberant concert hall. The library features five 2-channel stereo pairs, 10 main surround arrays, nine height microphone arrays for 3D main arrays and 15 4-channel configurations for surround and 3D ambience arrays, each with varied microphone polar patterns, directions, spacings, and heights. A dummy head and a first-order-Ambisonics microphone are also included. The library is provided with a rendering tool, with which the user can easily simulate different microphone combinations in both loudspeaker and binaural playback for 13 source positions. The audio inputs for the rendering tool can be directly fed from a DAW session as well as by manual file allocation. The MAIR library and rendering tool are available for free download from the GitHub link below.
VHAP (virtual hemispherical amplitude panning) is a method developed to create an elevated phantom source on a virtual upper-hemisphere with only four ear-height loudspeakers, based on the phantom image elevation effect. A set of constant power gain coefficients are applied to loudspeakers at ±90° and 0° for panning to a target azimuth and elevation in the front region, and to those at ±90° and 180° for panning in the back region. This plugin was written using JUCE, a cross-platform C++ application framework. It supports both loudspeaker and binaural rendering of phantom images over the virtual upper-hemisphere. In the binaural mode, a control of the perceived distance of an elevated image is also provided. The VHAP method can be used as a subset of the conventional 7.1 or 5.1 surround format (i.e. just using the centre, side (rear) left and right channels).
A web-based interactive tool that facilitates microphone array design and phantom image prediction is presented within this brief. Originally a mobile app, this web version of MARRS (Microphone Array Recording and Reproduction Simulator) provides greater accessibility through most web browsers and further functionality for establishing the optimal microphone array for a desired spatial scene. In addition to its novel psychoacoustic algorithm based on interchannel time-level trade-offs for arbitrary loudspeaker angles, another main feature allows demonstration of the phantom image scene through virtual loudspeaker rendering and room simulation via the Web Audio API.
SOFA for Max (Spatially Oriented Format for Acoustics package for Max MSP)
This database presents a new object collection for Max that enables the Spatially Oriented Format for Acoustics (SOFA) file format to be used within Cycling 74’s Max. The SOFA file format allows for easy distribution of and access to impulse response databases. This collection will allow for SOFA files to be easily opened and created from within Max so that they can be used in patches that utilise spatial audio reproduction.
360° BRIR & FOAIR (SOFA and Matlab library of 360° binaural and Ambisonic room impulse responses)
This is an open-access library of 360° binaural and first-order Ambisonics (FOA) room impulse responses (BRIR) captured in St.Paul’s concert hall in Huddersfield. Using a custom-made head-rotation system that was automated and integrated with the HAART IR measurement software, head-rotated BRIRs were acquired with 3.6° angular resolution for each of 13 different receiver positions. The BRIRs are provided in the SOFA format. It is expected that the database would be useful for studying the perception of spatial attributes in a six-degrees-of-freedom context.
3D-MARCo is an open-access database of 3D sound recordings of musical performances and room impulse responses. The recordings were made in the St. Paul’s concert hall in Huddersfield, UK using a total of 71 microphones simultaneously. The main microphone arrays included in the database comprise PCMA-3D, OCT-3D, 2L-Cube, Decca Cuboid, First-order Ambisonics (FOA), Higher-order Ambisonics (HOA) and Hamasaki Square with height. In addition, ORTF, side/height, Voice of God and floor channels as well as a dummy head and spot microphones are included. The sound sources recorded are string quartet, piano trio, piano solo, organ, a cappella group, various single sources and room impulse responses of a virtual ensemble with 13 source positions captured by all of the microphones. The database would be useful for spatial audio research, recording education and critical ear training.