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Re: Re: CVX tests

Subject: Re: Re: CVX tests
From: "Simon Squire" <>
Date: Sat, 27 Apr 2002 15:34:33 -0600
>
> The location in the housing may be providing some form of pressure
> "preloading" to the capsule diaphragm.

You agree with our designer...

>
> One could say that the MKH-20 plus a low noise pre is going to be more
> costly than the CVX, but the mics themselves are in a fairly similar
> price group. MKH like prices create that kind of expectation. The
> Telinga is also of the same sort of price, though it's not at all a omni
mic.
>

This is only true if they are designed for the same purpose.

>
> I'll be interested in following the saga. I do particularly like the
> weather resistance of the design. This, of course, makes it fairly ideal
> for a froglogger.
>
> Speaking of which, what are raindrops hitting it like for sound? Lets'
> say one of our typical summer thunderstorms. I'd kind of expect the
> housing may act as a drum.
>

When rain drops hit the CVX it definitely bangs!! Therefore the previous
discussions about "hogs hair" and other such covers is also true for the
CVX. I found a simple "hat" of loose polyester padding worked perfectly. No
bangs in heavy rain, and the water would simply run off the edge.

>
> So far it sounds ok. What appears to be the mic's noise floor is clearly
> noticeable in the recordings I've listened to. Though I certainly don't
> know if it's that or some other part of the process. I'm not surprised
> at this in view of the capsule used. Kind of like the things with the
> SASS mic, it would be nice to see some comparisons between the CVX as
> designed and say a "MKH-20" modification.
>
> Do you know if any frequency response graphs are available? Seems to me
> like the design may partially act to favor some frequencies over others.
>
> Walt
> 

The CVX also benefits from the PZM effect, but the housing gives far more
gain than just the 6dB. We usually quote around 14dB but this (like all
measurements) can be debated till eternity. Also the CVX provides more gain
as the frequency increases, which is great for birds, and making speach
understandable. From my perspective your numbers look ok, except several
assumptions. The only thing is that your conclusion about the frog not being
heard beyond 1/2 mile does not match what we actuall hear!!

Thank you for your examination. The CVX design definitely needs more
examination by knowledgable individuals, and field comparisons to mics like
the MKH-20. If you had one of these to spare for a little while, we would be
happy use it to challenge the CVX in the field.

Simon




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