AKG C 412
A one-inch F.E.T. condenser with a pattern switch and a 20 dB pad - and the paperwork argues about whether it has three patterns or four.
Overview
The C 412 is one of the more confusing entries in AKG's condenser catalog, and the confusion starts with the documents. According to the announcement in Recording-Engineer (October 1971, p.33), the C 412 is a F.E.T. condenser microphone system built around a one-inch diaphragm capsule. It has a pattern selector switch that steps from omnidirectional through cardioid to figure-eight, plus a switchable 20 dB output pad. The same notice says it can be phantom powered from the commonly available 24 V B+ supply in most input equipment, or from the a.c. and d.c. power supplies already sold for the AKG C-451E. That tells you where the C 412 sits in the lineup.
The pattern count is where the record gets slippery. A show report in a period trade publication lists the C 412 as "one of the first condenser microphones with four switchable patterns: omni, figure 8, cardioid, and super-cardioid," and a second show-floor listing repeats the four-position selector with super-cardioid added. The Recording-Engineer announcement stops at three. If you are chasing a C 412, check the actual detents on the switch of the unit in front of you. Don't trust either write-up.
AKG's own period advertising describes the capsule arrangement as a twin-diaphragm system. The DB-Magazine (June 1972, p.7) spread ran X-ray-style cutaway images of the one-inch capsule and its electronics under the line "with nothing to hide." The same advertising names the C 412 as an interchangeable component within the C-451E system family and lists the N-46E a.c. supply and B-46E battery supply as the outboard power options. It's marketing copy, not an independent verdict, but it does pin down the powering setup.
The C 412 earned its keep in the studio. Bruce Swedien's account of his drum setup, printed in a period recording publication, names the AKG C 412 alongside the Sennheiser MD421 and Electro-Voice RE-20 as his bass drum choices. The mic sat in a purpose-made drum cover with a port cut for it. That is not a spec sheet claim. It is a working engineer putting the microphone on the loudest source in a pop kit. A studio profile from the same era notes Indigo Sound in Manchester running four of the latest C412 microphones alongside a new AKG BX 20 reverberation unit, which suggests the model moved into British rooms in small batches rather than one at a time.
Powering is the practical headache. The C 412 will run from phantom-style d.c. present in a console or tape recorder, but the period documentation ties it to 24 V supplies and to the C-451E's dedicated a.c. and d.c. boxes. It doesn't assume modern 48 V behavior. Anyone buying one today should sort out the power question first, because the microphone is only as useful as the supply sitting next to it.
Beyond that, the documentary trail runs thin. No production years, no original price, no frequency response, no sensitivity, no self-noise, no weight and no connector pinout survive in the material assembled here. The C 412 is a real microphone with a real session credit and a real advertising campaign behind it, and almost nothing else can be stated with confidence. Expect to do your own verification on the bench.
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