Path of Miracles

A Multitrack Recording in 3D Audio to Recreate and Study Choral Blending

Interactive Project Report

Authors

Martha de Francisco (McGill University) [PI] and Ying-Ying Zhang (McGill University)

Published: May 14, 2024

Summary

In late August of 2022, the rich sonority of the historical Chapelle du Grand Séminaire de Montréal presented the acoustical canvas for a multifaceted choral recording and research project. Under the baton of Andrew Gray, Montreal choir Voces Boreales performed Joby Talbot’s Path of Miracles for mixed chorus (2005) and percussion, a musical pilgrimage for 17 voices, inspired by the millennial Camino de Santiago de Compostela.

Principal Investigator and Tonmeister Martha de Francisco directed the production using a precisely finetuned immersive multichannel recording set-up for 7.1.4 that included close and diffuse elements. PhD researcher Ying-Ying Zhang was in charge of implementing experimental spatial audio capture systems, including two comparative systems for capturing height and bottom layer reproduction and two second-order Ambisonics positions accompanied by 360-degree video. They were aided by a team that included graduate students from McGill University’s Sound Recording program, who assisted and visually documented the process.

The resulting recording serves multiple purposes, including a release in stereo and immersive sound as well as a sound installation that occurred at St. James United Church in downtown Montreal in June 2023. The extensive repository of recorded tracks will remain accessible to the ACTOR community. It will be at the center of choral blending research studies and expert aural analysis and comparative evaluations at the HfM Detmold and at McGill University, which will lead to future research outputs.

An immersive sound system in high-definition audio has been designed to record Voces Boreales from different perspectives, using 38 professional studio microphones (see schematic diagram below). When mixed, the various layers of sound present a vibrant and complete sonic picture of the performance. Using 3D recording techniques, a complex array of 7 omnidirectional microphones, placed in front of the choir in different distances and heights, is complemented by an immersive sound capture system of 6 omnidirectional microphones aimed at providing envelopment and a sense of integration of the acoustics. 18 cardioid microphones in the close range, one for each singer, as well as a stereo capture for the percussion instruments (bells and crotales), brings additionally a detailed close perspective of the individual musicians. This forms the basis for the sound of the installation staged at St. James United Church, a technical system for the performance of the recording by using 18+6 loudspeakers reproducing virtually the presence of the musicians performing the work.

Below you will find various photos taken during the recording session, which give a general impression of the microphone placement and physical dimensions of the recording space. In addition, the microphone placement schematic below contains links to learn more about the microphones used and how they were placed, and by clicking each link you can also hear an excerpt of the recording captured with those microphones only. In addition, a mastered final mix of Movement IV (Santiago) of Path of Miracles is available to stream below (MP3).

Credits

Path of Miracles (Jody Talbot, 2005)

Recorded at The Chapelle du Grand Seminaire de Montréal, August 26–28, 2022

PI, record producer, Tonmeister: Martha de Francisco
Performers: Voces Boreales, directed by Andrew Gray
Collaborators: Stratsimir Dimitrov and Ying-Ying Zhang
ACTOR Students: Marco Petrella and Mathieu Blanchet
ACTOR Partner (Detmold): Michael Sandner

Microphone Placement

The below schematic details the microphones used and their placement in the recording space. Each link contains a description of the microphone used, the rationale for its placement, and an excerpt of the recording captured through that microphone set. Below is a composite mix of the same excerpt.