Getting the vocal sound you want in live performance can either be a matter of luck, tradition (who could go wrong with the legendary SM58?), or better yet, understanding a few fundamental facts. In this article, we're going to demystify the mechanics and give you the guidelines you need to make the best decisions for your sound.
We'll cover some of the basics:
Pickup Patterns Is it a "cardioid world"?
Mic Placement How to hold the mic and where to place it, especially if you're using stage monitors
Keep in mind, though, that while the technical aspects of microphones are pretty rigid, how you apply them to the sound you're trying to achieve is not. Your vocal style, the band's vocal style, the kind of music you play and whether you're striving for a clear, natural sound or a specific effect will all influence the choices you make. And remember, too - it's all about your personal style. It's your sound.
Beginning to understand how microphones work will help you to understand their sonic differences. A good place to start is transducer types because every mic, whether wired or wireless is either dynamic or condenser.
What's a Transducer?
Live performances typically use a mix of dynamic and condenser mics.
If you cannot see the movie, you may download the Flash plugin here or simply click below to view the alternate PDF version.
Transducer Types
| Condenser mics receive their power through the mic cable from the input of the device to which they are connected, such as a mixer or mic preamp. This is called Phantom Power.
Phantom power is a DC voltage (generally ranging from 11 to 52 volts) that powers a condenser mic's electronics and, in certain models, provides a polarizing voltage for the capsule. Most often, phantom power is supplied by a mixer, but it can also be supplied by a separate, dedicated power supply. Most condenser mics can operate with phantom power voltages ranging from 11 to 52 VDC. For more information on phantom power, click here. |
Dynamic and condenser mics have different frequency response characteristics. Dynamic mics (like the SM58) tend to be "shaped", meaning there are more peaks and dips in the frequency response. Condenser mics are typically "flatter", and have more extended high frequency response.
What this means: If you're looking to accentuate mid-range frequencies in vocals or increase intelligibility, a dynamic mic might be your best choice. This is the sound most of us associate with full throttle rock and roll. On the other hand, if you want your sound to cover a wider (high and low) frequency range, e.g. to better represent your voice or achieve a more "realistic" sound, a condenser mic might be a better choice.
Again - it's a matter of experimentation
If you cannot see the movie, you may download the Flash plugin here or simply click below to view the alternate PDF version.
Pickup Patterns
|
The bass response of all directional microphones is increased as the signal source - your voice - comes closer to the mic capsule. This is called Proximity Effect and it becomes apparent at a range of one foot and increases as the distance of mouth to mic decreases.
For speakers or singers with high or thin voices, proximity effect can boost the bass, filling out the sound. To learn more about Proximity Effect, click here. |
Seems like a pretty natural thing, doesn't it? But how you hold a microphone so that only your voice goes into it, and not the other sounds that you don't want to pick up, is a science and not an art, no matter what you see on MTV. Keep the microphone close to your lips. You won't get the effect you want with a microphone an arm's length from your mouth.
Why?
The first reason is the inverse square law. If you hold your mic a half inch from your lips it receives a given amount of sound energy from your voice. Move it twice as far-one inch-and it receives one-fourth as much energy. That extra half -inch takes away three-quarters of the efficiency of your sound system. While good mic technique does include "working" the microphone, singers that fully extend their arm when reaching for that climax, are usually doing it for dramatic effect. Small changes in distance from your mouth can result in very dramatic changes in sound level.
Second: When you move the mic away from your lips, you must turn up the microphone level at the mixer to be heard, and more unwanted sound enters the mic. When sound from a monitor speaker enters the mic, it instantly becomes the earsplitting screech we know as feedback. (Helpful information on feedback can be found by clicking here.) Keeping the mic close to your mouth minimizes feedback.
To learn more about the Law of Inverse Squares, click here.
DO -Hold the microphone steady. -Mount on a stand to reduce handling noise -Hold it short distance (no more than 3" -4") away and point it somewhere between the nose and mouth. DON'T -Wave the microphone around. -Press it to your chin. -Cover the microphone by holding it at the ball grille. |
Gain Before Feedback is the amount of gain (amplification) that can be achieved in a sound system before ringing or feedback occurs. In live performance, you generally want as much of this as you can get.
To keep vocal microphones from picking up sound from the floor monitors that are facing you and other musicians onstage, place the monitor angled towards the least sensitive side of the microphone. With a cardioid pattern microphone (like the SM58), place the monitor directly behind the microphone. For supercardioid pattern microphones (like the Beta 58A), follow this simple diagram.
Some general guidelines to remember.
Decide on a condenser or dynamic microphone.
Keep the mic in close proximity to the sound source (voice) and as far away as practical from unwanted sound sources (such as loudspeakers or instruments) to reduce feedback.
Reduce pop (explosive breath) sounds by holding the mic either closer or farther than 3 inches from the mouth (because the 3 inch distance is worst) or by using a pop filter.
Reduce handling noise and stand thumps by using mic stands and accessory shock mounts.
There are many excellent sources for technical detail on the subject of vocal miking for live performance. In addition to numerous articles published on the Internet, we recommend the Knowledge Base on shure.com, or Shure's "Microphone Techniques for Music/Sound Reinforcement" available as a PDF on the shure.com literature cart.
|