Protecting & Cleaning Neumann Microphones
Due to the current COVID-19 pandemic we assembled this note on protecting and
cleaning Neumann microphones and accessories. Especially for vocal and speech
recordings, microphones are often used at close proximity to the mouth, possibly
also by multiple users.
To reduce the risk of spreading diseases through bacteria and viruses, one or
more remedies, explained in detail below, may be used:
- ideally, have just one user per microphone (including the accessories)
- after or before use, clean all surfaces, i.e. microphone housings, head
baskets and accessories
- leave the microphone unused for some time, possibly also applying elevated
temperature to the microphone
- utilize accessories such as windshields and thin plastic film bags to add
protection
Medical Disclaimer
This note assembles technical advice on which measures may be taken, and which
materials should be used or not used, to protect and clean microphones and
accessories without harming them.
For medical information on disinfection and disease spread please consult
your national and regional medical authorities and follow their advice.
Contents
1. Cleaning Neumann microphones
2. Time and heat
3. Protecting microphones with foam windshields
4. Acoustical effects of foam windshields
5. Protecting microphones with plastic film/bags
6. Acoustical effects of plastic film/bags
7. Further notes
1. Cleaning Neumann Microphones
Cleaning the microphone housing
For cleaning Neumann microphone housings from soiling including human
exhalations, you may use ethyl alcohol (ethanol) or isopropyl alcohol (isopropanol).
Used as a disinfectant, typically a 70% solution is used. Apply with a
disposable soft cloth, a soft brush or paper tissue. Make sure that the liquid
is applied only to the outside of the microphone and does not enter the inside
or the capsule.
Do not use rough materials which might scratch the surface. Do not use any
solvents stronger than ethanol or isopropanol, as these might damage the
surface.
Never use sprays, as these can deposit on the membrane and thus damage the
microphone capsule!
Cleaning removable microphone head baskets
With some microphones, the head basket can be easily removed for cleaning (KMS
104/105, KK 104/105, KK 204/205 and BCM 104/705). Make sure not to touch or
damage the capsule!
With the head baskets containing foam windshields, remove the inner foam and
clean it separately as described below (KMS 104, KK 104, KK 204/205 and the BCM
705).
Metal head baskets can then be cleaned also on the inside with ethanol or
isopropanol. You may also immerse the head basket in clean, hot water (e.g.
70°C/160°F). Do not use the dishwasher. Let the basket dry out completely before
re-assembly.
Personalized head baskets
BCM 104 and BCM 705 were constructed for simple switching between personalized
head baskets, so each user can use his own basket. Baskets for BCM are available
as spare parts:
Microphone |
Description |
Color |
Part no. |
BCM 104/BCM 705 |
Basket (BCM) |
Nickel |
576598 |
For hand-held microphones these head baskets are
available as spare parts:
Microphone |
Description |
Color |
Part no. |
KMS 104/104 plus |
Basket (KMS 104) |
Nickel |
513904 |
KMS 104 bk/104 plus bk |
Basket (KMS 104 bk) |
Black |
513903 |
KMS 105 |
Basket (KMS 105) |
Nickel |
079037 |
KMS 105 bk |
Basket (KMS 105 bk) |
Black |
079038 |
KK 104 |
Basket (KK 104) |
Nickel |
510306 |
KK 104 bk |
Basket (KK 104 bk) |
Black |
510307 |
KK 105 |
Basket (KK 105) |
Nickel |
094805 |
KK 105 bk |
Basket (KK 105 bk) |
Black |
094804 |
KK 105 HD |
Basket (KK 104 HD) |
Nickel |
510335 |
KK 105 HD bk |
Basket (KK 105 HD bk) |
Black |
510336 |
KK 204 |
Basket (KK 204) |
Nickel |
528689 |
KK 204 bk |
Basket (KK 204 bk) |
Black |
528690 |
KK 205 |
Basket (KK 204) |
Nickel |
528691 |
KK 205 bk |
Basket (KK 204 bk) |
Black |
528692 |
Cleaning the inner assembly/amplifier
The inner assemblies/amplifiers are typically enclosed in the housing and well
protected from outside soiling. Cleaning will hardly ever be necessary. Only a
soft brush should be used to clean off dust and soiling. Do not use any liquids
or solvents, as the insulation and sensitive parts of the circuit may be harmed.
Cleaning the capsule
If this should become necessary, it strictly must be done only by a skilled
serviced technician. The membrane is too delicate to be cleaned without the
proper expertise.
2. Time, and applying heat to the microphone
By taking a microphone out of action for a minimum of 6 hours, before putting it
back to use for another user, the infectiousness of human exhalations deposited
on the metal surfaces may be significantly reduced. For plastic or cloth
accessories, an extended period of 48 hours or more is needed to achieve similar
results. To accelerate this procedure, Neumann microphones may be heated up to
60°C/140°F without affecting the properties of the microphone. As not all
details are 100% assured facts to this day, please consult your national or
regional health authorities regarding the possible transmission via surfaces.
3. Protecting microphones with foam windshields
Foam windshield are mostly used to reduce wind and pop disturbances. But they
also serve to protect a microphone, at least partly, from rain, water, soiling
and human exhalations. Nylon pop screens are very thin and will hardly protect
the microphone from exhalations.
Cleaning foam windshields
Foam windshields may be cleaned with warm-to-hot water, up to 60°C/140°F. If
necessary, dish washing liquid may be applied. Thoroughly rinse the foam and let
it dry before putting it back to use. Moderate heat of up to 60°C/140°F may be
applied for faster drying. Do not use ethanol, isopropanol or other liquids or
solvents. Do not use the dishwasher.
4. Acoustical effects of foam windshields
Neumann foam windshields will affect the sound only slightly to moderately,
depending on the thickness of the foam. Typically, the high frequencies above 5
kHz will be slightly attenuated. This can be easily remedied with some
equalization of the recording. Likewise, small changes in the low frequencies,
including the bass boost by proximity effect, can be remedied with a low
frequency EQ.
5. Protecting microphones with plastic film/bags
This is not a typical use for microphones, and only some recommendations can be
given here. The main aim is to provide help for situations where no other
solution can be applied.
A foam windscreen will help, but it may not protect a microphone 100% from
exhalations. So, especially for multi-user applications, additional plastic film
or bags may be used as cover. Take separate disposable thin film material for
each user. Use bags with no ventilation holes and dispose of them after
single-use. Enclose all parts of the microphone that may become soiled.
Some hints:
- Use very thin plastic material
- Choose soft, flexible material to minimize crackling, fluttering, rustling, or
rubbing noises during the recording
- Leave some air volume around the capsule (e.g. the head basket, or use a foam
windshield)
- Do not tension or stretch the film tightly
- Make test recordings to become acquainted with your specific solution, how to
noiselessly handle the plastic film and how to best equalize the signal
6. Acoustical effects of plastic film/bags
Plastic film or bags will affect the sound of a microphone. Still, especially
for speech recordings, the response may be equalized to obtain usable quality.
Typically, plastic bags will produce these effects, increasing with the
thickness and stiffness of the film:
- Mid-range frequencies will be the least affected
- Roll-off at high frequencies, e.g. above 4-8 kHz
- Reduced directivity
- Reduced proximity effect at low frequencies
- Roll-off at low frequencies
7. Further notes
Omnidirectional microphones
These microphones are less affected by foam windshields and plastic bags.
Contemplate the possibility of using omnidirectional microphones also for
situations where otherwise you would have chosen a directive microphone. With
plastic bags, a simple high frequency boost above 3 kHz may already linearize
the response sufficiently.
Further Information
For further information please contact us at service@neumann.com or contact your
national Neumann distributor and service partners. |