The voice is our primary method of communication and our hearing is naturally tuned to its frequency range, making it the most instantly recognizable and arguably most important musical instrument of any song. Professional vocalists are capable of producing very low volume, nuanced tones as well as loud, harsh passages, sometimes within the same song. Since recording is as much an art form as a science, this dynamic range creates an exciting challenge for the audio engineer. The techniques used during this process will help to determine how effectively a vocal track mixes with the accompanying voices, instruments and ambient sounds that ultimately determine how impactful any song may be upon the listener. There are no hard and fast rules to this process, but we’ve provided some generally accepted theories that can prove useful in getting the most from your vocal tracks.
Professionals typically use large diaphragm condenser microphones for recording vocal tracks. Large diaphragms are well equipped to capture the sometimes substantial dynamic range of a vocal performance, picking up loud and soft passages effectively across the full frequency spectrum of the human voice. They are also more susceptible to “proximity effect”, an increase in low frequency response as a result of the reduced proximity of the vocalist to the microphone. This can create a pleasing effect on vocal passages when used carefully, and has been a distinctive trademark of radio DJs for generations. For vocalists with a naturally deep voice, this proximity effect may be undesirable and a microphone with a medium diaphragm capsule may be more appropriate.
The words “presence” or “intimacy” are often used to describe how “personal” a vocal recording sounds. The technical nature of this phenomenon can best be described as the relationship between direct sound and reflected sound. A vocal will tend to sound more “intimate” the closer the vocalist is to the microphone because the recorded track will feature a higher ratio of direct sound to reflected sound. As the vocalist moves further away from the microphone, the vocal will be characterized more by reflected sounds or room sound—the unique sonic signature of the particular acoustic space defined by its absorptive and reflective qualities. It is important to understand the final destination of your vocal track to determine the adequate degree of presence. Knowing in advance the variety and dynamics of other instruments that will comprise a finished song will be helpful in the setup process. Additionally, understanding the vocalist’s performance dynamics can help to mitigate the need for setup changes, overdubs, or re-recording.
A good starting distance for recording vocals is 12 to 18 inches away from the vocalist. Slight movements on the part of the singer will have much less effect on the mic output level if he or she is not “eating” the mic. While vocal mics are generally placed at the same level as the performer’s mouth, the mic can be raised to produce a more nasal sound or lowered to yield a more chesty sound. You can also experiment with angling the mic down at the performer’s mouth in order to avoid projecting breath energy directly into the microphone. However, avoid extremes that force the vocalist into unnatural positions which may divert their attention from the performance. Commercially available pop filters are highly recommended microphone accessories that are commonly used to soften plosives (like popping “p”s) by diflecting bursts of air away from the microphone diaphragm. Pop filters can also help in controlling a singer’s proximity to the mic. (See image “H”.)
There are a number of techniques one can employ when recording multiple vocalists. One common method for recording duets is using a multi-pattern microphone in bi-directional or “Figure 8” mode, allowing each vocalist to sing into opposing sides of the microphone. When recording multiple vocalists, as in a choral arrangement, audio engineers typically employ a number of small diaphragm microphones on telescoping microphone boom stands, or, if possible, hanging from the ceiling. Because the combined acoustic effect of a number of vocalists singing in harmony is more aurally pleasing than the sum of each individually, the increased amount of reflected sound audible in a live environment most accurately captures this natural phenomenon on a recorded track. There may not always be enough resources for separate microphones or recording tracks. (See image “I”.) For background vocalists or an entire vocal group, placing the vocalists in a semicircle around a cardioid microphone can achieve good results. . (See image “J”.) Adjusting the distance between each individual vocalist to the mic can achieve the desired balance in their levels.