Guidelines for miking vocals on stage.
Vocals, microphone set-up. Achieved knowledge:
You will achieve knowledge on how to mike vocals.
Written by Mikkel Nymand
When choosing a microphone for a vocal performance, audio technicians have a tendency to simply do exactly what they have seen on stages for years. Ask a child to draw a microphone and it will most likely be the legendary ice cream cone shape, well established by brands such as Shure. This is apparently what a vocal microphone should look like.
Why is this so? Which characteristic should we choose? How should it sound? How should it respond to details of the voice? Should we select stage monitors or in-ears? Wired or wireless? Stay tuned and follow the debate!
Why does a vocal microphone always look like an ice cream cone?
Handheld vocal microphones have a certain look for both historical reasons as well as for the fact that they need to meet certain audio needs. The most obvious being a steady handgrip and a controlled wind- and pop-suppression. Both of these basic needs require space in and on the unit, so companies must ensure that the shape of the vocal microphone is ergonomically-designed for the average hand. For most efficient wind- and pop-suppression, the furthest distance of the internal diaphragm from the mouth as is possible is ideal, which requires a certain grill size. At the same time, the overall size of the stage vocal microphone must be bigger than a small diaphragm condenser recording microphones and smaller than a large diaphragm cylinder “bird cage” studio microphone. For the performer, it should also appear to be large enough to “hide” behind (like having an instrument), but also small enough to provide a view that enables them to move around the stage and the audience to see them.
From a professional singer’s point of view, the sound color and general response of the microphone should be as true as possible to the sound of the performer’s tone. The human voice is a pristine instrument that should not be changed by a microphone fingerprint. Knowledge and experience teach us that this is best achieved with a condenser microphone capsule, which provides faster and more precise dynamics, as well as more linear response and higher resolution. Though this principle can be applied to stage performances, the challenge is to avoid noise and interference from other sound sources being picked up by the vocal microphone. It is often impossible to control both the vocal sound and the band sound, not to mention the surroundings. A condenser microphone has another unique characteristic in comparison to the dynamic: A condenser will linearly reproduce the natural level of sound sources at a distance, whereas a dynamic microphone will generally only react to nearby audio sources.
The psychological aspects of performing, especially live, should not be underestimated under any circumstance. From the talent’s perspective, the vocal microphone is their instrument and, as such, it is a precious and valuable tool – certainly not without emotional importance. Delivering the right perceptual value; how it feels, how much it weighs, what color it is – all these minute details matter to them, particularly when choosing vocal microphone. After all, it is important for most artists to find a microphone that is pleasant to use and perform with, as well as one that is able to help them in their artistic approach. Many excellent vocal microphones have entered the market so, for an artist, it is about finding the finest pearl in the necklace of brilliant vocal microphones.
When discussing vocal microphones for use in live settings, one specification that is most often referenced is the directional quality of the microphone. Since very few users will select omnidirectional handheld microphones for use on stage, sound technicians will need to decide which is the best directional pattern for each project. The main options they can select from are cardioid, supercardioid and hypercardioid. The can also choose headset microphones, which require placement close to the mouth and don’t require a directional pattern. Let us start with defining each directional pattern.
- A regular cardioid – also known as a first order cardioid – has approximately 6 dB rejection at ±90 degrees, with its highest rejection at 180 degrees.
- The supercardioid has higher rejection to the sides, approximately 9 dB, whereas it has a 180 degree back lobe at most frequencies. This pattern is reminiscent of the figure-eight microphone pattern from which it derived. User beware, ”super” is not necessarily better; it simply refers to higher side attenuation. Its highest rejection is at approximately ±125 degrees. Be careful not to confuse the supercardioid with the subcardioid (also known as a wide cardioid), a pattern which is in between a cardioid and an omnidirectional.
- The Hypercardioid is even more similar to the figure-eight pattern as it has higher side rejection,approximately 12 dB, and is also more open to the rear, with a rejection of approximately 6 dB).
All directionalities have their pros and cons. The most important item for the live engineer to consider when selecting a microphone is the varying rejection individualities of each unit. Understanding these and being able to incorporate them in their daily work is the key to getting the best audio from a microphone.
Gain-to-feedback ratio is the most necessary parameter to consider in live engineering. If the ratio between the levels of the voice was as high as that of all the other sound levels around it, we would have no problem. However, in reality, the voice is not able to compete with the stage monitors or loud instruments, such as drums and guitars. One thing to acknowledge in creating the perfect level is that a supercardioid microphone is more sensitive to sound from the rear than the cardioid. Those angles should be avoided when using a supercardioid. On the other hand, the supercardiod does have higher side rejection.
To make things more difficult, microphones actually change behavior when in use by a singing talent because the human head acts as an acoustic reflector for some frequencies. The most important concern in this situation is not whether to select a cardioid or a supercardioid, but rather the volume of the outside noise and which to avoid!
This is where the question of using stage monitors or in-ear system comes into consideration. It is not the scope of this article to discuss this, but seen solely from gain-to-feedback ratio struggle for the microphone, an in-ear system is preferred.
Proximity effect – how close can you go?
All matters have a cause and a consequence. For vocal stage microphones this is the typical scenario: Isolation from other sound sources is desired, so a directional microphone is selected.
Directional microphones are pressure gradient types using softer diaphragms, which are more compliant and create unwanted sounds that do not derive from the voice, like pop and wind. This is why most stage microphones need some sort of foam windscreens and pop filtering. User beware, foam windscreens may change behavior of the microphone’s high frequency response and directional characteristics. In many cases, even shock absorption is necessary due to the higher dispersion from softer diaphragm material.
In these cases, in order to obtain higher output, or to create a more intimate performance, singers often have their lips on the grid of the microphone head. But, putting their mouth too close distance to the microphone will result in an annoying acoustic distortion and will sound a bit rattled. (Try speaking with a finger right in front of your lips and you will hear!) Under these conditions, be sure to pay attention to the microphone’s ability to handle high sound levels, peak sound pressure levels at above 150 dB are not unusual for a singer who has the microphone right in front of their lips.
Experienced singers perform with a short distance between their mouth and the microphone, which will influence the bass level of a cardioid (pressure gradient) microphone.
Either way, the fact remains; when dealing with directional microphones, the bass level will be dependent on the distance between microphone and singer’s mouth. A good vocal microphone will have its proximity effect tailored to the purpose of use and will also feature a reasonable distance tolerance for it to work within.
Wired or wireless
The freedom to move around without cable is tempting, but still quite expensive compared to cables, and not entirely without noise and distortion. Normally, you choose your vocal stage microphone to be either wired or wireless. The d:facto™ Vocal Microphone
is delivered as a cabled unit, but it can neatly be customized to wireless use simply by unscrewing the microphone capsule and mounting it on a Wisycom wireless handle.