By Frank Lockwood
The recordings described here were done at the Church of St. Mary Magdalene in Toronto from January to May, 2009. This article is based on a presentation given by Frank Lockwood to the AES Toronto chapter in January 2014.
Recording The Music
For the main choir pickup, I chose a pair of Neumann KM 140 microphones. Specifically for the pickup of the room sound, I chose the Pearl TL4 two-channel microphone. Its unique construction features two separate microphones mounted back-to-back, facing 180 degrees apart from each other. This microphone is extremely well suited for capturing room sound, when the capsules are oriented so that they face the side walls. Pickup of the
performers here is de-emphasized, leaving that job for the main microphone array. The main pair was just behind the conductor’s position, and the choir was on the floor and the first step just by the communion rail.
In this flow chart, it all starts with the choir singing in the church sanctuary, shown bottom right. Their direct sound is picked up by the KM
140s and the reverberant sound is captured by the TL4. The microphone signals are amplified with the Millennia HV3D, digitized with the RME Fireface 800, and recorded by Pyramix in a series of takes.
“The Reproaches” is written for two choirs of different sizes, which alternate line by line. Because of this, the piece was never performed in its entirety, as the intention all along was to assemble it during the post-production phase. In all, 50 takes were made, with the choir and microphones in the same positions. A great deal of care was taken with the tuning, so that edits could be performed without having to worry about sudden pitch shifts.
Up to this point, this project conformed closely to the traditionally minimalist approach to classical music recording. Once the choir and the microphones were placed correctly and levels set, the sessions progressed through a series of takes, from which the best possible performances were selected to assemble the final presentation.
Dealing With Noise
In traditional classical music recording sessions, in order to reduce the intrusions from automobile and air traffic, heating and air handling, recording was done late at night with the heating turned off. As you might magine, recording a choir shivering in their winter coats at 4 a.m. might not be the ideal way to capture the best performance, so we recorded in the evenings, and while we turned the thermostat down, we didn’t turn off the heat completely. As a result, the recordings contained noises from inside and outside of the building. St. Mary Magdalene is on a three-way stop intersection, so vehicles are forever slowing down, revving, and then moving off again. By turning the heat down, the building started to settle and shift, resulting in several creaks and thumps that occurred at random intervals. Even with the fans turned off, the heating system still made a persistent whir the whole time.
I used iZotope RX to reduce or remove these noises entirely. The Spectral Repair tool is designed to address individual noises of short duration, and the Noise Reduction module reduces constant, long duration noise, such as fans or heating. The iZotope display shows a Spectrogram, where time is displayed left to right, and sound frequencies from low to high, from bottom to top. Louder sounds appear bright orange and quieter sounds are dark blue to black.
This first picture shows a short section where the gap between the end of one phrase and the beginning of the next is marred by a thump from somewhere in the building. You can see the vertical line near the middle of the display, followed by the trail of the reverberation.
Once the operation is completed, you can see that the thump is removed, while the prevailing room ambience is left undisturbed.
Removing continuous noise, like that from the heating system, requires a different tool. Here, an isolated instance of the background noise is highlighted so that the Denoiser Tool can analyze its frequency contour, shown as the blue line in the small window in the middle of the display. The program goes through the whole file, reducing anything that is quieter than that line, but leaving anything louder untouched – like the choir. The result is a choir performance in a much quieter church, allowing the listener to focus attention on the music more easily. I liken it to looking through a window before and after it has been washed.
Part 1 of this article appeared in the April 2014 issue of PS. Part 3, which will run in the August 2014 issue, will look at editing and processing the mix.
An expanded version of this article, with audio examples and more pictures, can be found online at www.LockwoodARS.com/production. Frank Lockwood is the owner/operator of Lockwood ARS. Based in Toronto, he specializes in classical and acoustic music recording, editing, mixing, restoration, and mastering.