Feedback / Microphone: Difference between revisions
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==Introduction== | |||
If you have questions about this article, please see this | If you have questions about this article, please see this | ||
{{Community|link=https://twitter.com/ST_Muso/status/1391466144138100736|text=Microphone Feedback discussion}} | |||
== What is feedback and how does it occur? == | == What is feedback and how does it occur? == | ||
Feedback occurs when the sound from the loudspeaker (or loudspeakers if a microphone is connected to more than one) is louder at the microphone than the sound of the voice. | Feedback occurs when the sound from the loudspeaker (or loudspeakers if a microphone is connected to more than one) is louder at the microphone than the sound of the voice. | ||
This fundamental fact is shown in the figure below. Note that in the diagram an L1 system is shown but the same fundamental fact is true for ANY loudspeaker. | This fundamental fact is shown in the figure below. Note that in the diagram, an L1 system is shown, but the same fundamental fact is true for ANY loudspeaker. | ||
[[Image:Feedback fig 1.jpg|400px|Microphone Feedback]] | [[Image:Feedback fig 1.jpg|400px|Microphone Feedback]] | ||
If you understand this diagram, it is relatively easy to understand how changes in an amplification system and the room can contribute to either increasing or decreasing the likelihood of feedback. | If you understand this diagram, it is relatively easy to understand how changes in an amplification system and the room can contribute to either increasing or decreasing the likelihood of feedback. | ||
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== Techniques For Reducing Feedback == | == Techniques For Reducing Feedback == | ||
=== Gain Staging === | === Gain Staging === | ||
Your setup should always begin with good gain staging and with microphones, that starts with great microphone technique. | Your setup should always begin with good gain staging and with microphones, that starts with [[#Close Microphone Technique|great microphone technique]]. After that, you can consider [[##Gain_Staging_2|gain staging your equipment]]. | ||
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=== Directional Microphones === | === Directional Microphones === | ||
==== Principles ==== | ==== Principles ==== | ||
Directional microphones | Choose a '''directional microphone''' to maximize gain‑before‑feedback. A [[Microphone Directionality#Supercardioid_/_Hypercardioid|Hypercardioid/Supercardioid]] pattern provides the strongest focus on the intended source, followed by [[Microphone Directionality#Cardioid|Cardioid]], with [[Microphone Directionality#Omnidirectional Microphone|Omnidirectional]] offering the widest pickup (the least desirable in most live sound applications). | ||
Directional microphones excel because they emphasize the desired sound—such as a voice or instrument—while naturally reducing sound arriving from other directions. This focused pickup helps maintain clarity and increases the system’s resistance to feedback. | |||
Most directional microphones also offer a helpful characteristic known as the [[Proximity Effect|proximity effect]]. As the source moves closer to the microphone, low and low‑mid frequencies become fuller and more pronounced. Microphones designed for close‑up vocal use take advantage of this: they deliver a natural tone at close range while reducing low‑to‑mid frequency content from distant sources, including nearby loudspeakers. This selective emphasis further improves feedback performance. | |||
Omnidirectional microphones, by contrast, maintain a consistent tone regardless of distance. This can be ideal in studio environments where uniformity is the goal. On stage, however, their equal sensitivity in all directions means they capture more ambient sound and offer less natural rejection of low‑to‑mid frequency energy. As a result, they provide less gain‑before‑feedback than directional designs. | |||
====Omnidirectional and Unidirectional Microphones==== | ====Omnidirectional and Unidirectional Microphones==== | ||
{{:Microphone Polar Pattern}} | {{:Microphone Polar Pattern}} | ||
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=== Distance Between Microphones === | === Distance Between Microphones === | ||
Another (low priority) design guide-line could be to keep open microphones as far apart as possible. Neighboring systems with open microphones can mutually decrease [[Gain Before Feedback|gain before feedback]]. | Another (low priority) design guide-line could be to keep open microphones as far apart as possible. Neighboring systems with open microphones can mutually decrease [[Gain Before Feedback|gain before feedback]]. | ||
== Techniques specific to the {{L1 family}} == | == Techniques specific to the {{L1 family}} == | ||
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== Other References == | == Other References == | ||
Here's a quick link to other articles about <categorytree mode="pages" hideroot="off" namespaces="Main">Feedback</categorytree> | |||
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* [http://www.shure.com/stellent/groups/public/@gms_gmi_web_ug/documents/web_resource/us_pro_mics_for_music_sound_ea.pdf Microphone Techniques for Live Sound Reinforcement] Shure Educational Publication 2006 39 pages - pdf format | * [http://www.shure.com/stellent/groups/public/@gms_gmi_web_ug/documents/web_resource/us_pro_mics_for_music_sound_ea.pdf Microphone Techniques for Live Sound Reinforcement] Shure Educational Publication 2006 39 pages - pdf format | ||