|
Microphones: Small Ensemble
Imagine you're the director of a small vocal swing group or ensemble. After a performance, a parent comes up and compliments you on a fine job. He tells you the group really looked good and the choreography was fun to watch. Then he says it would have been nice to hear them too! Anybody had this experience? I am sure many of you have, or at least some parents thought it but didn't verbalize it. Getting enough volume for a small group to be heard is often a difficult task. Let's look at some reasons many sound systems fail - and then look at some solutions. The Problem: Choreography The primary obstacle to good sound for the small swing group is the use of choreography by the singers. If the group is dancing or moving to different positions during the song, it is very difficult to get consistent sound, both in level and quality. If traditional microphones on stands are used, the singers are moving in and out from the microphones, so the volume level is going up and down. To complicate matters, the singers are often more concerned with the movement than the vocal quality. Their volume output is what usually suffers, and it is asking a lot of the sound system to amplify nothing. If you can't hear the singers, make sure they are projecting well before you fire the sound system operator! Figure 1
 A common method to mic a small group is to place microphones on floor stands in front of the group. However, there are several potential problems with this method. First, the vocal group is usually singing on a stage which has a hard surface. This floor provides a very good surface for the sound from the singers to be reflected off of the floor and back to the microphone (Fig. 1). This reflected sound is combined with the direct sound at the microphone. However, since the sound traveled to the floor first, this sound will take a little longer to reach the microphone. When the two signals are added together, distortions to the sound will occur. These distortions can produce unnatural sound and cause feedback to occur. The Solution: Microphone Placement Figure 2
 The solution is to place the microphone on the floor so the reflections are not a factor (Fig. 2). Several manufacturers make a foam "mic mouse" into which you insert your microphone. The foam provides some isolation from mechanical vibrations caused by the movement of the singers. Some microphones are designed for this application. They are often called boundary microphones. Be sure to only use directional boundary microphones to realize the greatest volume before feedback occurs. There is usually no need to amplify the audience noise, so make sure the microphone is facing the singers. How Many Microphones? Figure 3
 The number of microphones to use is not an easy question to answer. Many factors need to be considered, such as group size and arrangement. One rule to consider is the "3-to-1 Rule" (Fig. 3). The distance between each microphone should be at least three times the distance the microphones are from the singers. This assures minimum interaction between the microphones, which translates to better sound. Since gain-before-feedback is always a major concern, try using as few microphones as possible. Every time the number of microphones that are on doubles, the volume before feedback will drop 3 dB. In other words, just adding more microphones does not necessarily mean you will be able to get the group louder. In fact, it may work better with fewer microphones. Take some time to experiment with placement and the number of microphones. | 
| Take some time to experiment with placement and the number of microphones. | 
|
A word of caution is in order. The success of this method - or any method - is highly dependent on the rest of the sound system and its operator. The equipment must be quality gear, and engineered, installed and aligned correctly. Another method to obtain good sound is to use several of the singers to provide only vocals. They can concentrate on just the music while the others do the movement. If you are doing a musical, this small group could even be off-stage. The audience will hear good sound and they will see the dance. You can get the best of both arts. The microphones should be high quality, directional instrument type microphones. In other words, the microphone should have a flat, even frequency response and be very sensitive. The sound level reaching the microphone is very low because of the distance the voices are from the microphone. A microphone with high output (very sensitive) will require less gain from the microphone mixer, which means less noise. This requirement is best met by electret or condenser microphones, though there are some new high output dynamic microphones available. We'd like to help you by recommending a microphone for your application. Please call us. We want your vocal group to look good and sound great! by Ron Huisinga © 1996 Internet Sound Institute (www.soundinstitute.com). This article is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com
< Back
|
