> anyone that uses rycote windjammer can teach me how set up 'furry
> cat' the mics inside the windshield, to avoid that the rode rouches
> the structure? I was recording in the Wind, yes, the rycote with the
> windjammer atenutes a lot, but seems some problems velow 300 hz, when
> the Wind raises 20 mph.
> Any tip will much apreciated. thanks,
Juan,
The main purpose of a windshield is to part the passing air without causing=
turbulence which is the wind roar we don't want. Putting another windshield=
inside will alter the overall frequency response and possibly reduce the
bass roar, but it won't stop any wind turbulence generated by the outside
layer.
Many years ago in the BBC Film Unit I did some experimentation with the
available windshields, when Rycote first produced their plastic moulded
gardem mesh type. These whistled in the wind. I was already making a
waterproof cover (the Brinisock) for filming in the rain and this stopped
the whistling. Rycote took on my idea without the waterproofing, and the
rest is history.
The overall principle for avoiding wind turbulence is the size of the
outside of the windshield - the bigger and more rounded the better. You als=
o
have to think about the mount and boom, but these are less of a problem. An=
y
six inch windshield will cope with higher windspeeds than a four incher, fo=
r
instance.
Any surface between the mic and the main windshield will set up internal
reflections which may or may not reduce the wind noise, but once it has bee=
n
generated by turbulence over the outside layer, the bass rumble is there fo=
r
keeps.
A cover, especially a hairy cover, has the effect of enlarging the effectiv=
e
diameter of the whole windshield, while minimising the effect of a second
layer on the frequency response because it is at least in contact with the=
windshield. One layer you can get away with, with some effect on the
off-axis response, but a thick layer or two spaced layers will inevitably
change the sound from the mic.
To summarise, it is the outside of the windshield which stops the roar, and=
the bigger the radius, not what it is made of, is the key to stopping the
roar from higher wind speeds. As ever, I would experiment. 20 MPH wind is
quite a lot, and I would myself try an extra cover over the windshield.
Listen through various fabrics, hairy or knitted, put over your head to see=
how they transmit sound without muffling the HF.
If all else fails, try putting the mic on the ground where it often sounds=
better anyway.
David Brinicombe
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