If you’ve ever sung into a microphone, you’ll probably be familiar with the squeal or howl known as feedback. Feedback can potentially ruin a performance, so it’s important to know how to prevent it.
There are a few different things that can cause feedback, such as the type of microphone you’re using, where you position the microphone and the acoustics of the room. But don’t worry, there are some simple steps you can take to avoid feedback and make sure your performance sounds amazing.
What is feedback?
Before we look at the various ways to eliminate feedback, it’s important to know exactly what feedback is and what causes it.
Feedback is a type of acoustic phenomenon that occurs when sound from a loudspeaker is picked up by a microphone and then amplified again by the loudspeaker, creating a self-reinforcing loop. This can result in a loud and unpleasant squealing sound, commonly referred to as “feedback” or “microphone feedback.”
How do you stop feedback?
There are a few ways to help prevent feedback when singing with a microphone:
1. Use a Directional Microphone
Always choose a quality dynamic microphone with a cardioid or supercardioid pickup pattern. These pickup patterns are designed to pick up sound from the front of the microphone, while rejecting sound from the sides and rear. This can help reduce feedback, as the microphone will be less sensitive to sound coming from the speakers.
2. Position the Microphone Correctly
The microphone should be positioned at a distance of about 6-12 inches from your mouth, depending on the type of microphone and your singing style. The microphone should also be angled slightly downward to capture your voice without picking up too much background noise or ambience.
3. Adjust the Sound System Properly
The speakers and amplifiers in the sound system should be positioned and adjusted to minimize the potential for feedback. For example, the speakers should not be pointed directly at the microphone, and the volume levels should be set carefully to avoid feedback.
4. Acoustic Treatment
Acoustic treatment can be implemented to reduce reflections and standing waves in the room. Acoustic treatment can help to reduce the amount of echo and reverberation in the room, which can minimize the potential for feedback. This can include using absorptive materials on the walls and ceiling, or using diffusive materials to scatter sound evenly throughout the room.
5. Roll Off Low Frequency
Use a microphone with a low-frequency roll-off. Many microphones have a switch or control that allows you to roll off the low-frequency response of the microphone. This can help to reduce the risk of feedback, as low frequencies are more susceptible to feedback than higher frequencies.
6. Use a Pop Filter or Windscreen.
A pop filter or windscreen can help to reduce the amount of plosive sounds (such as “p” and “b”) that are picked up by the microphone, which can cause feedback. These devices can also help to reduce wind noise and breathiness, improving the overall sound quality of the microphone.
7. Use In-Ear Monitors
In-ear monitors (IEMs) can be an effective tool for reducing on-stage feedback, and are commonly used by performers in live music performances and other events. In-ear monitors allow the performer to hear a mix of their own voice and the music through headphones which can help to reduce the need for stage monitors or loudspeakers. This can help to reduce the potential for feedback, as there will be fewer loudspeakers on stage that could potentially cause feedback.
8. Reduce the Volume!
As the volume level increases, the risk of feedback also increases, as the microphone will be more sensitive to the sound coming from the loudspeakers. By lowering the overall volume of the sound system, you can reduce the sensitivity of the microphone and reduce the potential for feedback.
What is “Ringing Out” a sound system and how does this help to prevent feedback?
“Ringing out” a sound system refers to the process of identifying and eliminating feedback.
To “ring out” a sound system, a sound engineer or audio professional will use a combination of techniques and tools to identify the frequencies at which feedback is occurring and then apply equalization (EQ) to reduce or eliminate those frequencies. This process typically involves playing through the sound system and slowly increasing the volume until feedback occurs. The sound engineer will then use a spectrum analyzer or similar to identify the specific frequencies at which feedback occurs and apply EQ to reduce or eliminate those frequencies.
Ringing out a sound system is an important step in setting up a sound reinforcement system, as it can help to ensure that the system performs well and produces high-quality sound without feedback.
What are the best microphones for live vocals
To avoid feedback in a live setting, the best microphone to choose is a dynamic mic with a cardioid or supercardioid pickup pattern. The most popular in the music industry is, without doubt the legendary Shure SM58.
The Shure SM58 is known for its ruggedness, reliability, and versatile sound, making it a great choice for a wide range of singing styles and genres.
One of the key features of the SM58 is its cardioid pickup pattern, which is designed to pick up sound from the front of the microphone while rejecting sound from the sides and rear. This can help to reduce feedback and isolate the singer’s voice, making it a good choice for live performances where there is a risk of feedback.
In addition, the SM58 has a tailored frequency response that is well-suited to the frequency range of the human voice. This means it can accurately reproduce the full range of a singer’s voice, from the deep bass notes to the high-pitched harmonics.
Overall, the Shure SM58 is a versatile and reliable microphone well-suited to live singing. It’s a popular choice among singers and sound engineers alike, and is widely used in live music performances, public speaking events, and other applications where a high-quality microphone is required.