Microphone windscreen
A microphone windscreen, also known as a pop screen , is used to prevent interference in microphones . It usually consists of a cover made of open-pored foam and acts against low-frequency sound components and swirling air movements (wind) as well as the explosive sounds in human pronunciation. It is sometimes used in addition to a foam insert that is already available in the microphone basket.
Both the spelling of pop protection as well as pop protection and pop protection is common (Germanized from English: pop filter ). In addition, the synonym "Popkiller" has established itself.
function
The swirled air movements are to be considered relative to the microphone position: not only wind in the open air or blasts of breath produce swirled air, but also the microphone moving in still air. Wind protection devices are therefore also used for indoor recordings when the microphone (e.g. on a boom ) is swiveled and moved quickly.
Variants are the fur windscreen and the popscreen. All directional microphones are very sensitive to wind because of the pressure gradient . Pressure receivers , i.e. microphones with omnidirectional characteristics, are significantly less sensitive to air movements .
Dynamic microphones, which are usually designed with a cardioid characteristic, therefore very often have an internal foam. But some condenser microphones already have an integrated pop filter. This usually has no influence on the sound and does not affect the directional characteristic .
Executions
Foam windscreen
The windscreen, which is often designed as a sphere or ellipsoid and is attached to the respective microphone, is intended to prevent wind noise from disrupting the recording when recording outdoors. With microphone recordings, even a slight breeze can lead to strong interference (signal distortion) and DC voltage components ( offset voltages ) in the signal. A microphone windscreen allows wind noise attenuation of the low frequencies of 30 to 60 dB, depending on the design. Supportive one should on location subsonic filter ( low cut filter or high-pass filter ) may be connected.
When used in the vicinity of TV transmitters, a foam windbreak is often used as a way of branding or logo labeling .
When speaking to microphones in close proximity , it serves as protection against annoying pop sounds. Therefore, it is associated with reportage handheld microphones and pop screen , Plopschutz or Popkiller called. Pressure-gradient react at close-talking very sensitive to low-frequency shock waves as close to the mouth at the pronunciation of front plosives ( [p] , [t] , etc.) and also fricatives ( [f] , [s] , [ʃ] , [x] etc.), affricates ( [pf] , [tʃ] etc.) arise. The disadvantage, especially of a foam windscreen, is a certain attenuation, even of particularly high frequencies.
Basket and fur wind protection
A variant of the windshield is an additional basket that completely encloses the microphone and is covered with gauze . This has only a low level of height attenuation, but reliably keeps wind off.
In general, a large free volume, limited by a gauze basket, results in greater attenuation of wind noise than a smaller one. In the case of very strong air movements, a plastic fur cover can also be pulled over this basket. In the jargon this is called windjammer , fur , dog , poodle , puschel or cat or deadcat . This also prevents wind noise by the hair dampening air turbulence around the basket. Windscreens with fur trim are also common for clip-on or hand-held microphones and are particularly suitable for extreme wind conditions. The way the wind protection works is based on deflecting and breaking the wind so that it cannot penetrate to the microphone capsule.
The required large volume around the microphone can be achieved with a microphone basket, large-volume foam bodies or other large-volume constructions. As a rule, the protective effect is increased by a cover made of synthetic fiber fur.
Pop protection, pop protection
In recording studios , pure pop protection variants are mostly used. The microphone is not enclosed here, but a flat membrane (similar to a nylon stocking ) is installed in front of the microphone, which filters the air vortices. Such a pop screen often consists of a ring-shaped frame that is covered with a mesh fabric. There are variants with single or double covering.
The pop screen is usually attached to the microphone stand with a gooseneck and placed about 5 to 20 cm in front of the microphone. As a positive side effect, they protect the studio microphones from droplets of saliva and define a minimum distance between the speaker and the microphone.
Rather the exception are models with a metal shade. In this case, the wind is swirled so that it does not hit the microphone.
imprint
Radio broadcasters often produce windbreak shapes in striking colors and provide them with the respective station logo so that their own brand is conspicuously presented on television broadcasts . In the case of particularly extravagant shapes, the acoustic quality of the windshield / microphone system suffers.
literature
- Norbert Pawera: Microphone Practice . 4th edition, Franzis Verlag GmbH, Munich, 1993, ISBN 3-932275-54-3 .
- Thomas Görne: Microphones in theory and practice. 8th edition, Elektor-Verlag, Aachen, 2007, ISBN 978-3-89576-189-8 .
- Michael Dickreiter, Volker Dittel, Wolfgang Hoeg, Martin Wöhr: Manual of the recording studio technology. 7th completely revised and expanded edition, published by ARD.ZDF medienakademie, Nuremberg, 2 volumes, publisher: KG Saur, Munich, 2008, ISBN 3-598-11765-5 or ISBN 978-3-598-11765-7 .
