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Re: pressure build-up ring

Subject: Re: pressure build-up ring
From: "David Kuhn" dkuhn012001
Date: Tue Nov 11, 2008 2:04 pm ((PST))
Thanks Walt, I did mean to de-couple it, so as to observe the 
difference between the SASS and the PB Ring, while still having some 
way to hold up the mics on my tripod stand. Someone, can't find out 
who it was, said in the thread that the SASS works the same as the PB 
Ring, and you confirm that, as do my results. 
And thanks again for the mod SASS--it is my main gear for soundscape 
work, which is mostly what I am doing now, recording as many as I can 
in Hawaii. I spend a lot of time just listening with it.

Your caution taken re: the screw.

Aloha,
David

--- In  Walter Knapp <> 
wrote:
>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.


> 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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