2025 will mark the 65th anniversary of Sennheiser's MD 421 dynamic microphone. 15 years ago, there were more than 500,000 MD 421s out there, making this iconic, incredibly versatile microphone one of the best-selling and most popular mics in existence. It's been used on countless recordings and innumerable tours, on everything from vocals and guitar amps to drums, percussion and brass. With a storied history and a vibrant future, the Sennheiser MD 421 is a microphone that should be in every musician's mic locker.

Table of Contents

The History of the Sennheiser MD 421
   How Did Sennheiser Start?
   The Development of the Sennheiser MD 421
What Are the Best Applications for the Sennheiser MD 421?
   What Makes the Sennheiser MD 421 So Versatile?
   Miking Drums with the Sennheiser MD 421
   Miking Guitars with the Sennheiser MD 421
   Miking Vocals with the Sennheiser MD 421
   Miking Horns with the Sennheiser MD 421
Current Sennheiser MD 421 Offerings
   Sennheiser MD 421-II
   Sennheiser MD 421 KOMPAKT
One Mic to Rule Them All?

The History of the Sennheiser MD 421

Before we dive into just what makes the Sennheiser MD 421 such a popular choice across an amazingly wide range of applications, we'd like to take a quick look at the history of Sennheiser and the development of this legendary mic.

Pictured: Sennheiser MD 421-II

How Did Sennheiser Start?

Founded in 1945 by Dr. Fritz Sennheiser and seven fellow engineers from the University of Hannover, the company that would become Sennheiser was originally known as Laboratorium Wennebostel (usually shortened to "Labor W"), after the town in which it was located. Sennheiser, who had built his first radio at the age of 11, already had several innovations under his belt, including an early reverb system. He would later invent the first shotgun mic in the mid-1950s. The company changed its name to Sennheiser Electronics in 1958. Sennheiser (the company) built their initial reputation on a series of dynamic mics designed for broadcast use, the DM2, DM3 and DM4. But what would be the real precursor to the MD 421 would arrive in 1953—the MD (for microfon dynamische) 21.

The Development of the Sennheiser MD 421

The MD 21 became incredibly popular with broadcast outlets because it sounded good, looked sleek and professional—coming in several colors—and proved to be both rugged and reliable. It was a very good, but basic, no-frills mic. It was also omnidirectional, so it was prone to feedback when amplified, and was less suitable for public address and the increasing use of microphones in musical performances.

Pictured: Sennheiser MD 421-II Close Miking Guitar Amplifier

So, in the late 1950s, Sennheiser, along with design engineers Paul-Friedrich Warning and Johann-Friedrich Fischer, began work to develop a new, cardioid version of their popular broadcast mic for intended use as a studio mic for the burgeoning recording industry. It was a project that would be an interesting engineering challenge.There were a number of design requirements for this new mic that would, in combination, create that challenge. It was to have "studio-quality" bandwidth (30Hz–17kHz, where most dynamic mics at the time tended to be in the range of 50Hz–15kHz), handle very high SPL, have a hum-compensation coil for dealing with RFI/EMI issues in the recording studios of the time, and have adjustable bass roll-off. It also had to be rugged, easy to manufacture in quantity and relatively affordable. Though many of these features are common today, in the late 1950s, they were on the edge of what dynamic mics were capable of.

One of the biggest challenges was designing a microphone capsule with a cardioid pickup pattern that did not require rear-facing ports. [Ed. Note: Virtually all mic capsules are inherently omnidirectional. For more details, check out our article on How Dynamic Microphones Work.] Many of the existing cardioid mics of that time had such ports, and they could potentially be covered up by mic clips or simply holding it, having a deleterious effect on the pickup pattern. By using a clever internal acoustic chamber, which coupled to the separate chamber holding the large (1.1") dynamic capsule via a frequency tuning pipe and four small vents at the rear of the mic, Sennheiser was able to accomplish this goal. This system also enabled better control of low-frequency directivity, and this voicing was enhanced by the rotating five-position bass roll-off switch at the base of the mic. And the large capsule enabled the mic to handle SPL as high as 160dB.

Pictured: Sennheiser MD 421-II Bass Roll-Off Switch

On its release in 1960, the MD 421 was an almost instant success, becoming widely adopted, not just in the studios at which it had been aimed, but in broadcasting and live sound as well. To date, Sennheiser has sold well over 500,000 MD 421s, and there is no indication of demand slowing for this amazingly versatile mic.

What Are the Best Applications for the Sennheiser MD 421?

So, just how versatile is the Sennheiser MD 421? Well, here's a quick—and certainly partial—list of some of its more illustrious appearances in the studio and on stage:

George Harrison's Concert for Bangladesh featured the MD 421 on, well, pretty much everything. In the same way that the SM57 was used on almost everything for the Woodstock Music & Arts Festival, Harrison and his sound crew broke out several cases of Sennheiser's headlining dynamic for the famed Madison Square Garden concert. The MD 421 has been referred to as "an SM57 on steroids" by guitarist/engineer/producer Brian Tarquin.

Lindsay Buckingham famously used MD 421s for his vocals with Fleetwood Mac on both Rumours and Tusk.

Producer Glyn Johns used the Sennheiser stalwart for both vocals and guitars on Eric Clapton's Slowhand album.

More contemporarily, Tom Morello used an MD 421 for guitar on both the sessions and tour for Evil Empire.

Queens of the Stone Age's Josh Homme used the mic for vocals and guitar on Rated R.

Finally, superstar producers Chris Lord-Alge, Bob Clearmountain and Dave Pensado have all referred to using the mic as one of their production tools.In addition, the Sennheiser MD 421 has been used on drums for pretty much everything except overheads on so many recordings and tours that we can't even begin to count. It's popular for horns, either solo or covering sections, again, both live and in the studio. It is one of those "Swiss Army" mics that's capable of so much that you could (almost) get away with your mic locker just being MD 421s (though we really recommend a little more versatility than that, we certainly understand the urge).

Pictured: Sennheiser MD 421-II Miking Tom

What Makes the Sennheiser MD 421 So Versatile?

There are a number of factors we've touched on that combine to give the Sennheiser MD 421 so much range and versatility, but let's put them together in one place:

MD 421 Feature	Drums	Guitar Amps	Vocals	Horns
Extended Freq. Response	Catches both low-end punch and stick attack	More “hi-fi” than traditional choices	Helps add a little “air”	Smooth high-end eases excessive brightness
High SPL Handling	Stays clean when it gets loud	Stays clean when it gets loud	Tames “shouting” vocalists	Stays clean when it gets loud
Cardioid Polar Pattern	Minimizes bleed	Minimizes bleed	Minimizes bleed	Minimizes bleed
Bass Roll-off Switch	Controls excessive rumble	Compensate for proximity effect	Compensate for proximity effect	Helps adjust response for horn section

To expand a little on those points:

1.   Extended frequency response: At the time it was designed, the 30Hz–17kHz frequency response exceeded what was then held to be "studio-quality" response. It's still pretty respectable for a dynamic mic, and the high-frequency response is quite smooth and not brittle.

2.   High SPL handling: 160dB is enough to cause permanent physical harm to you, but this mic can just shrug it off, so it's great for close miking of really loud stuff like drums and horns, and cranked-up guitar amps.

3.   Excellent off-axis rejection: This is especially handy in live situations, unless you carry iso booths for your stage performance (not a great look). Reducing audio bleed from other sources is almost always a good thing.

4.   That bass roll-off/high-pass frequency control: From removing stage rumble, to taming proximity effect, the five positions help you tune the response before you have to start adding EQ.

All that being said, let's get a little more granular with the applications.

Miking Drums with the Sennheiser MD 421

First up, probably the most common use for the Sennheiser MD 421 is on drums. Although you'll generally see it on toms, the MD 421 is a frequent snare mic as well, and even does well on kick, thanks to its large diaphragm, high SPL rating and adjustable high-pass filter. With good overheads, it even makes a pretty good hi-hat mic, since it tames some of the harshness you can get on close miking the hat. The key to placement here is to not point it too directly at the drum head (except for kick drum use), but have it angled so it picks up both the edge and center head tonality of the drum. The addition of the MD 421 KOMPAKT to the line, with its smaller size and included drum mount, makes this an even easier choice, and makes the mic less of an inadvertent percussion device when your drummer gets a little carried away.

Pictured: Sennheiser MD 421 KOMPAKT Drum Clamp

Miking Guitars with the Sennheiser MD 421

The second most popular use for a Sennheiser MD 421 is on guitar amps. The seemingly disparate combination of the mic's inherent warmth and its expanded high-frequency response couples with the slight decrease in transient response from the large diaphragm to make for an articulate, not overhyped response, even on the most roaring amp. The extra 2kHz on the top, compared to common choices for amp miking, like the Shure SM57 or Sennheiser e 609, also provides a more “hi-fi” quality. One thing to remember here is that a dynamic mic's response tends to drop off more quickly with distance from the audio source than condenser or ribbon mics, so keep it close. For live, we're very fond of an MD 421 about an inch off the grille cloth, aimed slightly off-axis to tame some of the spikiness that can come from an on-axis placement. In the studio, add a ribbon or a condenser about a foot or so back from the speaker to add some dimension.

Pictured: Sennheiser MD 421 KOMPAKT Close Miking Guitar Amplifier

Miking Vocals with the Sennheiser MD 421

Although condenser mics are the most frequent choice for vocals in the studio, for some voices, a dynamic is a better selection. The MD 421 is especially flattering for male voices that tend to be a little bit nasally or thin because of its powerful proximity effect. If you're getting a little too much low end in the voice, you can use the bass roll-off control to back it off a little. One trick we've seen done in these situations is to also have a condenser in the vocal booth running to a separate track so you can add a little "air" later if you feel you need it. If you’re doing that, just be careful with placement to avoid phase-cancellation issues.

Miking Horns with the Sennheiser MD 421

Horns are loud, and they can be quite bright. So, the Sennheiser MD 421's combination of high SPL handling and smooth high-frequency response has made them a frequent choice to cover brass and woodwinds, either as a pair to cover a horn section, or as a single mic for a featured soloist (or both). Horn sections are loud enough that the sensitivity drop from distance with a dynamic mic isn't so much a thing. A stereo pair of MD 421s, about six feet apart, aimed at the center of a three-piece horn section will give a great stereo image that slots into a mix nicely, and a third one, roughly centered, that a soloist can step up to when it's their turn to blow works well both live and in the studio. If the band as a whole tends toward the louder side when playing live, you're probably better off with individual mics for each performer, and just ride the fader for solos.

Current Sennheiser MD 421 Offerings

The Sennheiser MD 421 has been in continuous production since 1960, making it one of the longest-running mics ever. While there have been a few changes along the way—for example, the original Delrin mic bodies didn't handle UV or temperature extremes well, which is why, if you find an original one, it's almost always riddled with cracks—the mic, by and large, is mostly unchanged from the original design. That being said, Sennheiser is currently offering two different MD 421 variations.

Pictured: Sennheiser MD 421-II and Sennheiser MD 421 KOMPAKT

Sennheiser MD 421-II

Why It's Cool: It's instantly recognizable and still sounds just as great as it ever did.

Things to Consider:

• Incredibly versatile
• Size can make it a little hard to place in tight situations like miking toms, or on small stages
• Lighter than you'd expect from the size

Shop Now: Sennheiser MD 421-II Dynamic Microphone

When Sennheiser designed the MD 421-II (which could be a little confusing, because the very first version was the MD 421-2) their aim was to make the mic more easily manufactured while keeping the classic, balanced, natural sound and look of the original. We think they did a pretty good job at that. It remains one of the most versatile mics on the market, despite being almost old enough to collect Social Security. One thing we like about it is that, when you see them on stage, you know the band (or at least the sound engineer) is serious about getting it right.

Sennheiser MD 421 KOMPAKT

Why It's Cool: It's got the same great sound in a smaller, more convenient package.

Things to Consider:

• Includes a drum mount to simplify your life
• Make using one for guitars on smaller stages way easier
• Does not have 5-way bass roll-off switch

Shop Now: Sennheiser MD 421 KOMPAKT Dynamic Microphone

Besides being as cute as the dickens, this shrunk-down version of the MD 421 is, indeed, KOMPAKT. Easier to fit into a drum kit (and with an available drum mount, sold separately or bundled), the new low profile works better on smaller stages or in tighter quarters for guitar amps and horns as well—all without compromising the classic MD 421 sound.

One Mic to Rule Them All?

From broadcast announcement mic to multi-platinum albums, the Sennheiser MD 421 has been a staple for audio engineers in the studio and on stage from its debut in 1960. One of the top-selling mics of all time, it is certainly deserving of a place in anybody's mic locker. Is it the answer to every thorny recording or sound-reinforcement problem? No, nothing is. But if something was, it would probably bear a pretty strong resemblance to this instantly identifiable icon. You can check one out for yourself—and probably fall in love with it—at your local Guitar Center store. Or dial the call center and talk to one of our knowledgeable Gear Advisers who can help you determine if an MD 421 is right for you.