The MD 421 was created in 1960 by Sennheiser. It was used in the field of professional sound technology but also in the field of amateur. Television users knew this microphone as the press conference microphone in the 1970’s to the 1980’s. The MD421 was pushed back from this field after the 80’s due to people wanting smaller looking microphones. Although it is still used quite often in the music world for the way it picks up drums, brass and percussion sounds.
The MD 421 is a dynamic front address microphone; to properly use it you just speak right into the logo. This is because the MD 421, at a directional index of 1000 Hz and 180 degrees is at least 18 dB, so the sound from the back with a frequency of 1000 Hz produces an 18dB lower signal as sound from the same intensity reaching the front. The MD 421 has a large diaphragm that is cardioid dynamic. It has a humbucking coil for low noise pickup. It has a 5 position bass rolloff switch, this helps to minimize the sound of shaking the microphone. The MD 421 has a high frequency response from 30 – 17,000 Hz with high sensitivity and a slight increase in response to high frequencies. Below are some pictures of the MD 421’s polar pattern, its frequency response and the dial on the bottom of the MD 421 that helps to sculpt the low end.
The MD 421 has a very high tolerance of SPL and is decently vesicle; because of these features it works great around loud noises. Lots of people use this microphone to mic toms, horns, electric instruments, kick drums and even loud speakers. My experience with this microphone is that it sounds great on axis but if you go off axis you will get a sort of sound leakage. This is because the cardioid dynamic microphone isn’t that tight. When I tried to mic this up to a drum set it had some weird multi phasing issues around the multi mic area with the drum kit. When I did finally get the tom set up the off-axis leakage caused the cymbals to sound weird and phasey. This caused me to bump my rating down to 3 stars. Something I think this microphone could work well for is recording a screamo singer in a studio. Because the MD 421 is really good at recording loud noises and in a studio our singer would not need to be moving off the axis or have other microphones near by. If you want to hear what the MD 421 sounds like when someone signs into it there is a video here. If you are interested in the MD 421 some other microphones in its family are: the MD421-U that has a 3-pin plug that is symmetrically wired and fitted with a roll-off filter, the MD 421-2 that has a large 3 pin Tuchel plus for European broadcasting wired symmetrically and is a low-impedance microphone with no roll-off.