From: Mike Feldman <>
>
> Walter Knapp wrote:
>
>
>>> ... assumption of double diaphragms.
>
>
> Right, it's an assumption about multi-pattern mics... thanks,
> Walk for digging that up.
I'd passed right over that little factoid numerous times before it
finally sunk in.
>>> It's not necessary to have double diaphragms. Sennheiser, in all the
>>> series from MKH-20 to MKH-800 use the same general capsule design, and=
>>> it's a single diaphragm. They put the diaphragm between two acousticall=
y
>>> transparent plates. They call this a "symmetrical push-pull capsule"
>
>
> So they're not mixing two diaphragms to get multi-pattern. I suppose
> they could be mixing two backplates... but that wouldn't work unless
> they're also mucking with the acoustical path on one side. I'd really
> like to understand this.
Obviously, the MKH-20 houses the capsule quite different from the
MKH-80. I'm pretty sure that the patterns of each single pattern mic are
generated by the housing design. Not sure how it's done on the
multi-pattern, I'm not a mic designer, just a user. The 80 housing is
symmetric with the capsule clearly visible. I do know it does do
multiple patterns very well.
>>> Here's their description from their general discussion of the MKH in
>>> their Microphone Brochure:
>
>
> The SennUSA and SennEng websites are a pain to navigate, and I can't
> find a brochure that says that, so it's time to look for technical
> papers to see if they explain how they get multi-pattern in the MKH-80(0)=
.
I believe I got the brochure off the main european site, though it could
have been through one of the others. It has more stuff than the
individual mic pdfs in the form of brief descriptions. Very handy to
have it all in one pdf. It's 5 megs worth, so a bit of a pain to move
through my modem. I could try if you want it.
If you come across any good papers on this stuff I'd be interested.
Understanding how a mic works can help in using it. I do understand how
the rf part of a MKH works, but the multipattern is somewhat of a mystery.
Walt
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