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Re: pressure build-up ring

Subject: Re: pressure build-up ring
From: "Wil Hershberger" wil_hershberger
Date: Tue Nov 11, 2008 12:23 pm ((PST))
Yes, Walt you told me about the screw and the potential for O-ring  
damage.
Do you have a photo of exactly how far forward the mics should be to  
take maximum advantage of the PZM coupling?
Thanks,


Wil Hershberger
Nature Images and Sounds, LLC
Hedgesville, WV
The Songs of Insects
My Blog



On Nov 11, 2008, at 3:12 PM, Walter Knapp wrote:

> Posted by: "David Kuhn"
>
> > I perceive no difference between with and without the PB Rings--good
> > data up to over 40 KHz. To apply them I pushed the mic's forward  
> from
> > the SASS body about 1.5 inches, then slipped the rings on. All
> > recordings were with the SASS tripod mounted with 15 foot  
> extension--
> > the bats came very close to check it out.
>
> Just a note, some random thoughts:
>
> When you move the mics forward of the SASS boundary you will remove  
> the
> acoustic coupling between the diaphragm of the mic and the boundary of
> the SASS housing.
>
> The pressure ring is just a small boundary you substitute. The SASS
> housing boundary works the same but is larger.
>
> I would think that this would make a difference only at low  
> frequencies.
> But the repositioning of the mics that far forward will change the
> barrier characteristics and thus what you will have is no longer the
> SASS as designed. It is something else experimental.
>
> As you already discovered the bored hole does allow the mics to be  
> moved
> forward. You should limit how far forward so the small screw near the
> connector end of the mic does not chew up the back o-ring. I'm pretty
> sure I told everyone I made a SASS for about this screw.
>
> Walt
>
> 







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