Paul,
Your measurements are interesting. My guide is only rough and not
measured. I found that adding a layer of foam to the lycra actually
added to the wind noise rather than reducing it, but I've found a
single layer of lycra to be remarkably effective and acoustically
transparent. You need a design where it stretches taut over the mic
housing. An air gap of an inch or more between layers can also help.
Currently I'm experimenting with knitting a beanie cover from mohair
(to go over the lycra cover), after finding that a mohair scarf was
acoustically transparent and helped a lot with wind noise.
Walter Knapp always had good ideas for DIY windshields, might be
something in the archives or on his web site.
cheers,
Vicki
On 08/09/2010, at 3:28 PM, Paul Jacobson wrote:
>
> On 08/09/2010, at 2:47 AM, Steve Duncan wrote:
>
>> Does anyone know of any sites that go into windscreen design or
>> experimentation, ala diystereoboundarymics or similar?
>>
>> I've gotten my capsules wired and mounted, but wind protection
>> needs to be integrated into the final design.
>
> Hi Steve,
>
> Thanks for bringing this up :)
>
> There are a quite a few sites with how-to's on building windscreens
> but as far as I know there is anything that I'd classify as
> "experimentation" in the sense of conducting tests to evaluate
> performance.
>
> I've done a couple of quick tests to follow up on observations that
> a layered fleece-foam-fleece construction was having a significant
> effect on HF content. The following observations are relative to an
> uncovered, flush to boundary mounted AT3032.
>
> - A single layer of thin fleece seems to cut frequencies at 4khz by
> around 2dB as a worst case.
> - Adding a layer of thin foam to the fleece increased attenuation
> to 4dB at 3khz, and added a roll-off above 8khz resulting in 4dB
> attenuation at 12khz.
> - A pull on wind-cover made with two layers of lycra and thin foam,
> rolls off from 1khz to attenuate by 5dB between 4khz and 6khz. The
> level of attenuation drops back to 2dB at 9khz before rapidly
> increasing to 7dB at around 14khz.
> - An old, battered Rycote Windjammer cover pulled over the same
> setup attenuates 2dB between 2-6khz, is 1dB down between 7-8.5khz,
> then rolls off to attenuate by 4dB at 12khz.
> - The Rycote has 1-1.5dB less attenuation than unlined "yeti fur"
> between 2-10khz, and has up to 4dB less attenuation above 10khz.
>
> The challenge seems to be to find materials and construction that
> reduce the impact of wind noise, but which are "transparent" in
> terms of influence on sound. At this point I'm seriously
> considering cannibalising the Windjammer to replace the lycra-foam-
> lycra cover I currently use.
>
> cheers
> Paul
>
>
>
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