The instrument
The AKG D 3400 microphone was probably launched in 1991 as part of a whole range of dynamic vocal and instrumental mics.
Details
"In order to produce a high output signal, the microphone is built using a proprietary Neodymium/Iron Boron magnetic system. The diaphragm design came about after studying the motion of various diaphragm structures using holographic analysis. (...) It has a high frequency extension and is designed to roll off steadily below 200Hz" (muzines)