R/E/P Community

R/E/P => Klaus Heyne's Mic Lab => Topic started by: klaus on January 24, 2018, 08:15:25 PM

Title: Gallery Of Greats
Post by: klaus on January 24, 2018, 08:15:25 PM
In this gallery I describe the all-time greatest microphones I have come across in my work.
Among them may be some surprises and sleepers that are often overlooked.

Head over to my website https://germanmasterworks.com/publish/articles/galleryofgreats.php to browse.
Title: Re: Gallery Of Greats
Post by: radardoug on January 25, 2018, 03:59:36 PM
Nice Klaus! Wasn't aware of the KM88. Pictures soon please! Pix have been added since this post. KH
Title: Re: Gallery Of Greats
Post by: panman on January 26, 2018, 01:25:36 PM
Yes Klaus, that was nice and well done. Thanks!
Title: Re: Gallery Of Greats
Post by: ratite on January 30, 2018, 09:18:02 AM
Don't the earliest ones have more bass?Where's the damn book Klaus? ;)
Title: Re: Gallery Of Greats
Post by: klaus on January 30, 2018, 01:26:26 PM
Quote
Don't the earliest ones have more bass?
That was a joke, right?

Title: Re: Gallery Of Greats
Post by: David Satz on January 30, 2018, 07:39:10 PM
No, it's not necessarily a joke. Some years ago I noticed a substantial difference among Neumann's published frequency response curves for the KM 88 especially in the figure-8 setting, but also in the cardioid setting. Two sets of those curves are attached here. I posted a question on the late, lamented Neumann Pinboard about it (I think in 2004; I will try to find the exchange), and Martin Schneider explained that the capsules in the final batch of KM 88 microphones had increased diaphragm tension because (if I remember correctly) a Swiss radio organization had placed a sizable order for them, specifically for use as announce mikes.

--best regards
Title: Re: Gallery Of Greats
Post by: klaus on January 30, 2018, 07:57:28 PM
If that special-order batch at the end of the KM88 run exists, it would be great to add details to my narrative.

Short of details, those mics, if they existed, would have LESS, not more bass than the bulk of the series. They also would have the revised head basket- easy to tell.
Title: Re: Gallery Of Greats
Post by: uwe ret on January 30, 2018, 11:21:56 PM
Increased diaphragm tension = less low frequency sensitivity (less bass)!
Title: Re: Gallery Of Greats
Post by: ratite on January 31, 2018, 01:08:17 AM
That was a joke, right?
I was remembering poorly, David Satz's contention. Hence earlier more bass...

Given that some of the first headbasket type must have had capsule replacement it always concerned me when looking for KM88's.I have 2 88's with 5 pin small tuchels and an 88i but have never thoroughly compared them.

BTW: which SDC has the best bass in Fig 8? KM86 with the gap between the capsules a bit greater?

This came up when I was looking at Ambisonic mics and the original Soundfield Capsule designer claimed there were no terribly bass responsive fig 8 SDC's, even those resolved from an ambisonic array, and therefore that pattern use in outriggers/DECCAs/double MS was problematic (apologies for sidetrack).
Title: Re: Gallery Of Greats
Post by: Timtape on February 01, 2018, 12:03:58 AM
No, it's not necessarily a joke.
If the bass difference is much more pronounced with figure 8 and cardioid, compared to omni, perhaps proximity effect is a factor?
 
Title: Re: Gallery Of Greats
Post by: David Satz on February 01, 2018, 11:39:02 AM
Timtape, I raised this question on the Pinboard after comparing the frequency response curves that Neumann had published for all their microphones in 1973 (in a standalone, four-page flyer printed on green paper), in 1977 (Catalog 100), in 1980 (Catalog 110), and in 1984 (Catalog 120). Response curves for other switchable-pattern microphones, such as the KM 86 and U 87, were included in the same publications. Those sometimes differed slightly from edition to edition, but not nearly to the degree that the KM 88's curves changed between catalogs 110 and 120.

Klaus, I can't find this exchange on the Pinboard any more; perhaps it wasn't kept when the archive section was set up. But I don't think that this was a special order in the usual sense, where only the one customer got "variant" capsules; rather, I think that some time between 1980 and 1984 Neumann changed this parameter of the K 88 capsule for all subsequent production, as the published curves indicate.

--best regards
Title: Re: Gallery Of Greats
Post by: klaus on February 01, 2018, 02:21:25 PM
(...) rather, I think that some time between 1980 and 1984 Neumann changed this parameter of the K 88 capsule for all subsequent production, as the published curves indicate.

My problem with that scenario: Neumann , to the best of my knowledge, did not produce nickel capsules in the 1980s anymore, so where would new ones with different specs (higher diaphragm tension) have come from?
Title: Re: Gallery Of Greats
Post by: David Satz on February 01, 2018, 10:39:02 PM
Apparently the K 88 was the last nickel-membrane capsule that Neumann produced, though, continuing more than a decade after the capsules for the KM 54 and MM 5 had been discontinued. The "Übersicht der von NEUMANN gebauten Mikrofone und Mikrofonkapseln" from the "Infopool" lists the KM 88 as having been produced from 1969 through 1986--and that's consistent with the catalogs and price lists of the time, as well as what Martin wrote on the Pinboard.

--If you want to add a bit of real trivia concerning the KM 88: It was originally going to have just two patterns. See the attached scan from the 1968 fet 80 catalog; there are other examples.
Title: Re: Gallery Of Greats
Post by: klaus on February 02, 2018, 01:22:47 AM
(...) It was originally going to have just two patterns.

That corresponds to the evolution of the DC converter, which did not come to fruition until the late 1960s. Without DC converter = no figure eight for that model.
Title: Re: Gallery Of Greats
Post by: David Satz on February 21, 2018, 07:23:36 PM
Klaus, I found the Pinboard messages about the change in the KM 88's low-frequency response. The essential one from Mr. Schneider is PBD_11554, dated Sept. 1, 2003 (i.e. from the original arrangement of the Pinboard, before its active part was divided into three sections).

I don't think it would be right to post the message here without permission, but its essential point is, the diaphragm tension was increased (thus reducing the low-frequency response especially in the figure-8 setting) because this improved operational reliability when the microphones were used for speech pickup in radio broadcasting. He said that this change had been made in about 1982.

--best regards
Title: Re: Gallery Of Greats
Post by: klaus on February 23, 2018, 04:28:36 PM
Hello David,

What you unearthed from the obsolete Neumann Pinboard is indeed fascinating.

As KM56/SM2/SM23 capsules were used in KM88 which were discontinued in the mid-1960s, Neumann must have increased diaphragm tensions on existing capsules in their shop for the last batch they sold.

This would have addressed the on-going issue of arcing holes in these super-thin nickel diaphragms, especially when the mic is used for spoken word: close-up use and consequent 'plosives exacerbate the arcing problem.

It is indeed possible to increase diaphragm tension on these capsules by carefully adjusting assembly components (I have done this), but  it can be hit and miss, trying to dialing in a specific outcome on a metal diaphragm thinner than 1µ, so I assume quite a few capsules were trashed in the process.