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Originally Posted by
trustyjim
β‘οΈ
Very interesting post PM01! I'm sure it would be helpful to everyone here if you could share a little info about yourself and how you came by this knowledge.
The knowledge comes from various sources, mostly being the older B&K master catalogs. Back in the 1960s, they were thin little books, literally half the size of a magazine cut in half widthwise. Also, B&K published lots of technical books that were dated from the 1950s on up. B&K only published the master catalogs once every few years. In 1974, they were about the size of a moderate population phone book, approaching 700 pages and hardcover. The other master catalog I have is dated 1989, and is probably one of the last ones made before they switched over to advertising "slicks". The 1989 edition is about 910 pages and has the section dedicated to the first studio microphones, the classic 40xx series.
Pretty obvious that someone at B&K had a love for music and the recording of, otherwise the big wigs at B&K would have never allowed such a venture to go into studio / live recording. Traditionally, the mic responses at B&K were meant to be as flat as possible for scientific measurements. The repeatability aspect comes from their durability and their use of materials as well as adhering to the ANSI S1.12-1967 standards as well as the IEC-651 standards. Sort of like the ISO9001 certification several decades before the ISO9001, Six Sigma, etc came about.
Engineers and techs in the field wanted to make sure that the microphone and measurements that they were taking could be easily referenced, and that they had a standard of measurement. B&K keeps several "reference standard" mics available on site as well as off locations. They measure the unknown mics to the reference mic at a specific temp, specific humidity and specific barometric pressure. 23 degrees C, 50% relative humidity, 1013 mbar of mercury. Very serious stuff. Plus the engineers and techs wanted to make sure that the mic that they were using didn't drift significantly over a period of time.
For those mics that are subject to high temperatures, they list a certain amount of hours that they are good for. 150 degrees C is fairly toasty for any mic, but certain B&K mics will do the job nicely. I do believe that at the high temp rating, the mics are only good for a few hours.
And if that wasn't enough, some of the mics allowed for a dehumidifier attachment, basically a chamber of desicant gel that can be rebaked that is installed behind the microphone cartridge.
The modern day versions of the DPA 40xx series studio mics are identical to the ones that B&K produced back in the late 1980s. Same materials, same response, same build quality. The only thing they might have changed are the internal preamp board components for the mics. Usually they switch over to different parts, same value. This is done since manufacturers of discrete components won't produce the same part forever.
Durability of the mic cartridge is also part of the build. I've seen B&K mics submerged into faucet water and then dried off. Perfectly functional. Mind you, this is just the capsule portion of the mic. B&K did this to simulate the moisture encountered with a active singer - that of sweat and saliva. Fairly nasty combo to any mic, but the stainless steel/nickel diaphragm handles it with no problem. If I have anyone behind the mic, I'd rather use the DPA/B&K in case they are like Sylvester the cat with all of his spitting. Granted, the pop filter stops most of it but I don't want to see the damage it does over time with a mic diaphragm made from mylar.
The mic cartridge is also robust enough to survive a 1 meter drop onto hardwood with less than a 0.1dB change across the entire operating range. Fairly impressive since the diaphragm is a thin foil.
Now this may all sound like good advertising for DPA, and it is. But the fact is that DPA doesn't have most of the information that I mentioned on their site. Reason being - it's way over too many heads for their customers. DPA would much rather concentrate on providing info that the studio manager/recording guy can understand. That's why they publish papers pertaining to the placement of mics, AB, XY, recording techniques and tips, etc. This is a wise move on their part as many recording engineers that I know of won't have a high level science degree. Quite frankly, it's not needed in the recording studio. Keep it simple and have the recording engineer understand what some of the effects of sound will be, whether it come from the room, acoustic attenuation through materials (foam egg crates anyone?), how the mics react to sound and other sources, etc. They really don't need to know that the diaphragm of the 4041SP/T 1 inch mic is 2 microns thick and made of nickel / stainless steel foil. Or the longevity of the mic in dB shift per hundreds of years. That's more for the physics/science guy.
As for me, definitely applied science guy. Good mix of book and street smarts with the practical knowledge in the industry to back it up. And I find a huge interest in what manufacturers aren't telling you. Fortunately, the parents (B&K) are more than willing to talk while the kids (DPA) get to play. Other companies aren't so nice and they just look at you funny. heh