Sennheiser MD 421-II by John Eppstein
This is one of the world's most well known and recognizable dynamic cardioid microphones. It has been a staple in studios and sound reinforcement since the 1960s. Many people love 'em. Some people find reasons to hate 'em. Why is that?
Let's look at the good side first. It's a large diaphragm cardioid dynamic with a humbucking coil for low noise pickup. It has a 5 position bass rolloff switch. (So why did I only give it a 7 for features - I'll get to that). Of course for recording in any reasonable conditions you don't need and probably shouldn't use a bass rolloff anyway, but it's got one in case you want to record vocals during an earthquake. The mic is ubiquitous - you see it everywhere (I own 4 of them). While its most common uses are on close miced toms and horns it has been used as a vocal mic by acts like Pere Ubu and The Grateful Dead, although it's large, bulky black body does nothing for its popularity with singers who want their faces seen. And the clip, well, I'll get to the clip later. The mic has a very high tolerance of SPL and is also often used on electric instrument cabinets and occasionally on kick drum, although it's not really the best kick mic around (It's still a hell of a lot better than an SM57). The mic itself is reasonably rugged and can take quite a few drumstick hits without dying.
So why the relatively low ratings?
Well, this mic also has a few problems. Let's start with the clip.
This mic has, beyond any reasonable doubt, the worst mic clip of any common microphone and possibly the worst ever designed. It's hard to use, unreliable, breaks extremely easily, and is expensive to replace. And no standard clip made fits this microphone. The clip is a flat piece of plastic on a swivel which slides into a slot and locks (kinda) with a spring loaded button mounted in a hole through the plastic. Unfortunately the hole weakens the plastic so if you twist it the wrong way getting it on of off it snaps.. The button is not always a positive lock - sometimes you mount the mic on the clip, it seems to be secure, and next thing you know it's on the floor. OTOH sometimes once you get it on you can't get it off, which is prime time for a broken clip. Did I mention that you can only get clips that work from Sennheiser and they're a bit pricey, especially for a clip that breaks frequently? Yeah, you guessed it, the clip is the reason for the low feature rating. I should actually take off a couple more points. It's REALLY bad.
The other problem is that it has certain sound quality issues. Don't get me wrong here, the on axis response is very good. That's not the problem. The problem is the off axis response, which is all over the map. And since the pattern is not all that tight as cardioid dynamics go, there will generally be pick up of leakage. This can and does make for weird phasing issues when used in multi-mic arrays - like around a drum kit, for example. Also when used on toms the off-axis leakage can cause the cymbals to sound weird and phasey and mess with your snare sound. It also means that room leakage picked up can sound pretty funny in a not good way. When micing guitar cabs the direct reflection off the floor can cause the tone to get weird. How much the off-axis sound thing bothers you has a lot to do with how you feel about this mic. Live sound guys often aren't bothered. It drives many discerning studio engineers nuts.
Like I said, I have 4 of 'em. As I do more studio and less live I find myself using them less.
Mine are all the original MD421U - I don't have any of the new MKII, but reports I've heard are that none of the problems have changed and the main differences relate to the automated assembly line. I do know it still uses the same silly clip.