When recording, for example, a contemporary choir backed by piano, bass, and drums in a natural hall environment, the backup will be picked up by the choir mics, and will sound boomy and unfocused if not carefully controlled. Fortunately, most halls have a built-in solution: reception spaces and other rooms with doors opening into the hall. The drums and bass can often be located here. If the bass is acoustic, some sound will enter the hall, but considerably less than if the instrument was in the hall. Communication for the instrumentalists, and conductor if necessary, can be achieved with headphone fold-back and video monitors.
Typically in such a space, one would mic the piano by putting mics inside the piano, closing the lid, and perhaps even encasing the piano in packing blankets. This produces a distinctive sound, but does not take advantage of the natural piano sound in the room. Instead, position the piano with as much distance from the choir as is possible, and balance its pickup with the leakage into choir mics. During sound check, experiment with your post-production plans (EQ, compression, etc), as getting the right balance has to happen now.
Miking technique alone will not give you the kind of control you need to produce a full “studio” sound. Once you have captured a full choir sound, you will find that the room characteristics will define the choir sound as being in a natural acoustic space, and this will not balance well with the drums and bass.
An old trick used for “fattening” up the sound of a guitar involves double tracking the sound source, applying compression and expansion to one track, and then mixing the two together. The choir pickup will have unneeded bottom end from the omni mics, so in the processed track, much of this can be rolled off. You can also narrow the stereo width of the processed version of the choir, using the unprocessed original to create a sense of depth and width. You can delay this track as well, although care must be taken with possible phase cancellations, leading to an unnatural choir sound. Also, any processing done to the choir sound will impact the piano sound, and vice versa.
The sound of the hall has now become an integral part of the choir sound, and can be blended with the backup ensemble tracks, sweetened with appropriate reverb.
Earl McCluskie is a producer/engineer and Owner of Chestnut Hall Music, a music production company based in the Waterloo region of Ontario. The company specializes in location CD recording, both live and session. Recent projects have included Vancouver-based composer Timothy Corlis with the DaCapo Chamber Singers, Montreal’s violinist/composer Helmut Lipsky and soprano Suzie LeBlanc, and the Guelph Symphony Orchestra.