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Re: Figure 8 mics (Sennheiser MKH pdf)

Subject: Re: Figure 8 mics (Sennheiser MKH pdf)
From: "Rob Danielson" danielson_rob
Date: Sat Jul 29, 2006 8:48 am (PDT)
At 4:36 PM -0400 7/28/06, Walter Knapp wrote:
>Posted by: "Rob Danielson"
>>  Increased clarity is how I'd describe the difference as well. I used
>>  a 30/40 pair for the front M-S on my 744T surround rig for two years
>>  and switched to a 80/40 pair a year ago. The 80 seems to have
>>  extended response under 50Hz and noticeably smoother lower-mid
>>  response.  The most evident upper end noise on my 80 is about a 1/3
>>  of an octave higher. There's less graininess to notch-out around 8K
>>  Hz (compared to the MKH-30). In quiet natural locations, the output
>>  of my MKH-40  (which was bench- tested with the 30 by Sennheiser)
>>  typically produced 2-3 dB more output than the MKH-30. My MKH 80
>>  produces 2-3 dB more sound file saturation than the 40.   There are
>>  several solid plusses with the 80.  Rob D.
>The Sennheiser mic brochure pdf is too big for me to put up, but I
>extracted just the MKH portion and have put that pdf up temporarily here:
>Get it now if you want it, can't guarantee how long I can keep it up.
>It's just under 900K.
>There have been several comments that touched on polar patterns or
>frequency response, rather than trying to respond to each, the pdf has
>Sennheiser's graphs for these as well as the rest of the mic specs for
>the MKH. This info is a start on how they will behave, field experience
>is the bigger part.

Nice .pdf!  My reading of the charts is consistent with what I gather 
in the field. For example, there's a low-end rise in response 
starting at about 35Hz for the MKH-80 in Figure 8 while the chart for 
the 30 only goes down to 50Hz. In my surround work, I use 1-3 
sub-woofers that are pretty flat down to 16Hz so I'm working with 
that content regularly.

>The 30 and 40 are supposed to have the same sensitivity. I've noticed as
>well that when used in M/S the 30 will often have a little lower output.
>Not sure but what it may simply be that we are pointing the 40 more
>directly at the area of interest. The difference is less when the
>soundfield is wide and fairly even. Or that the figure 8 naturally
>splits it's sensitivity to two different areas in some way.

Possibly, but aren't the frequencies below 50Hz from distant sources 
very diffuse in most settings?   When I play signals recorded in the 
dead of night from a MKH40 and MKH30 split through a bi-amped speaker 
system, the content below 40Hz for the MKH30 is less loud, less even 
and more prone to exaggerated tones that create "bounciness."

My studio tests suggest the NT2000 might have a strong low end in fig 
Message: 8. 
Subject: Its not realistic for me to plan on buying more mkh80's/800's so I 
have to find an alternative-- which will have me accepting other 
weaknesses with the NT2000 or whatever mic I go with. Many factors to 
determine and rank.  If the NT1-A mics I'm using for the rear pair 
didn't handle moisture so well, I don't know what I'd be using there 
to be honest. The response of the NT1-A's is weak under 250 Hz 
(except for a big boost at 30Hz and lower) and the upper end is 
grainer than I'd prefer. The NT2-A is less grainy on the top end, but 
its more prone to moisture problems. The improved lower mid clarity 
of the 80 over the 40, 30, 60 NT1-A, NT2-A, AT3032, MBHO and many 
others I've tried is pretty evident when I mix. I rented a pair of 
20's and generated material I frequently mix with, but I don't have 
nearly as many hours comparing the 80 to the 20 as I do with the 
other mics. I agree with you that the 20's performance could be 
between the 40 and the 80 in terms of flat frequency response and 
lower-mid clarity.

>It may also be a problem that most mic testing is done at fairly high
>sound levels and they don't entirely behave the same recording much
>lower levels.

I believe the charts would show us some very relevant differences in 
performance if the tests were run at low sound levels and possibly 
with more detail. Eric tests off-axis frequency response in his lab 
in 1/3 octave steps which I understand is much more painstaking than 
what manuf's do. I'd also like to see the tests to state accuracy or 
tolerances of the test gear.

So, right, its back to recording and listening and trying to figure 
out how to get the gear to do what we think its capable of doing. Rob 

>I'm not surprised at the 80 having higher output than the 40, it's
>sensitivity rating is much higher. That's my experience too. Even more
>evident in a way when you go to a pair of 80's for M/S.
>Regardless of which mic when I'm doing M/S I adjust gain on each mic
>independently thus focusing on getting a good recording from each mic.
>Only later in decoding the M/S do I work on the balance between them.

Rob Danielson
Peck School of the Arts
University of Wisconsin-Milwaukee

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