Are Dynamic Mics Dead?

January 1, 2001

Howard Stern and Don Imus couldn't be more different. Stern uses a condenser mic, while Imus works behind a dynamic. The two most visible radio hosts in America embrace the two major families of today's air studio mics. Which is best for your station?

Condensers and dynamics weren't always the big two. Many broadcasters spoke to us over ribbon microphones, whose image has come to symbolize an era. Large, robust and flattering to voice, these mics were in wide use well into the 1960s. Condenser, moving-coil and carbon mics were also on the air to some degree, but wide-bodied ribbons such as RCA's 44, 74 and 77 were king.

Not that they were without a few problems. Although ribbons are usually described as smooth and warm, these mics typically had a rather low output level, were large, heavy and somewhat fragile, and required periodic ribbon replacement. (I should add that modern ribbons have solved these problems, although there seem to be very few ribbon mics in use on the air.)

The post-war generation of dynamic microphones also solved these problems. As a group they were less expensive, less fragile, usually more compact, and easier to make unidirectional.

Condenser microphones offered the most accurate response and widest frequency range, but they too came with unwanted baggage. They were expensive. They were fragile. Their sensitivity made them ill-suited for close-micing. They required a power source. And I will repeat: they were expensive.

It was natural that dynamics should dominate broadcasting as ribbon use faded. Dynamics gained in popularity with a surprising array of 1960s and 70s vintage types such as Shure's Unidyne (the Elvis mic), SM-5 (and later SM-7), SM-57 or EV's RE-16, many of which are still in use today.

A quick peek at studio web-cams reveals a scattering of Shure SM-7 and Sennheiser 421 types amid a forest of RE-20s and RE-27s. Today these two remain the most popular on-air mics. They're rugged, fairly inexpensive and sound great on voice. Can they remain dominant in the digital age?

Industry insiders observe that a new generation of condenser mics is poised to make a run on this industry standard. Why? Because many of the problems inherent in condensers have been solved.

Price has come down considerably. Classic models still carry a hefty price tag but many quality cost-efficent products are on the market now as well. One factor hastening the new models is improved design and manufacturing techniques available in the industry. Another is the fact that competition over market share is extreme, pitting well-known major manufacturers against young upstart companies and even companies from former Soviet-bloc nations. But the most significant reason these mics are less expensive is that they are much simpler than their older siblings. Most of the new mics, it seems, are single-pattern cardioids.

Classic designs, such as the Neumann U87 and AKG C414, offer a variety of pickup patterns by employing a second diaphragm. Sound energy collected from front and back diaphragms are added or subtracted in order to achieve the desired polar pattern — omni, cardioid or figure-eight. The simple single-pattern design eliminates this second diaphragm. We're left with reduced cost at the expense of pattern flexibility. Because the vast majority of situations call for cardioids, this is typically an acceptable trade-off.

Years ago, the transistor also changed the game. In substituting solid-state electronics for vacuum tubes, these mics eliminate bulky external power supplies. The mic bodies can be made more compact too, a significant factor in a cramped control room — especially where the operator/announcer must be able to see copy, a computer monitor, an interview subject, or all of the above. Solid-state also means more rugged. In the real world, accidents happen. Some of today's microphones are designed to withstand quite a bump, although we don't recommend you explore this envelope at home.

Another part of the changing face of microphones today is the emergence of smaller companies such as CAD, GT, Marshall, Rode, Soundelux and Joe Meek. Their products originally found fans in the home-studio market, and now the mics are edging into broadcast. These companies are introducing products at all price levels, going head-to-head with the major mic makers.

Meanwhile, the big names in condenser mics aren't exactly napping. Shure's KSM-32 was joined this season by the top of the line multi-pattern KSM 44. If there is a single condenser that has found widespread, long-term use in broadcast it is Neumann's U-87. Neumann's catalog offers some less-costly alternatives in the TLM-103 and TLM-193. (Though not large-diaphragm, Neumann's KM-180 series is also worth mentioning, as is the KMS105 — designed as hand-held stage mic but with great potential for on-air.) AKG has an extensive array of voice-specific mics including the C 4500B-BC, and Audio-Technica's single-pattern AT4047/SV has attracted some interest, notably in the public broadcasting sector. Still, condensers have considerable ground to make up.

Dynamics have many advantages condensers can't touch. They're rugged; able to survive nearly anything an exuberant jock (or butter-fingered engineer) can dish up. They're simple, quiet, and don't require a power supply. And the most expensive dynamic doesn't come close to the cost of traditionally priced condensers.

The choice is yours

Picking a studio mic is often a balancing act. What do I want in the perfect mic? Sound quality is of foremost importance, but after that opinions vary. Of course, cost is right up there. If you're equipping several studios with two or three high-end mics, costs can mount fairly quickly. Opinions are more varied on the subject of uniformity. Do you insist on having identical mics at every chair? Or is this a place you can save a few dollars by having less costly mics at the secondary positions? Form follows function, and so does the bottom line. Some would point out that it is more important to have the right mic on each voice than it is to be uniform. Obviously, this is easier to achieve if your crew has sole access to a particular studio and can lock down its setup.

The uniformity issue also comes into play for guest mics. Certain microphones can be more difficult for non-professionals to address correctly; a more “forgiving” type — wider pattern or less susceptible to popping — may be called for. There may not be much to be gained by having identical mics all around the studio if guests sound poor.

In budgeting for your new mics, dynamic or condenser, don't fail to account for proper windscreens and shockmount suspensions. Many are type-specific to each mic and are often included in the package price. (Some also come with a nice very nice case which you'll never use for anything except maybe paper clips.) Other mics offer these accessories only as options. Be prepared to pay up to 20 percent more for such add-ons. Also, be advised that some of the suspension mounts are rather bulky. If sight-lines in your studio are already an issue, trying to work with of one of these elaborate “birdcage” shock mounts may force you to rethink your choices. Select a boom arm capable of supporting the full weight of the mic and its mount. Pay close attention to its proper location. The boom should place the mic within comfortable reach of anybody: from young children to your ex-all-pro-linebacker sports guy. Proper placement should never compromise being able to see the equipment and vice versa.

For some stations, the move to a studio condenser will be complicated by the need to deliver phantom power to the mic, as a surprising number of popular consoles are not so equipped. The simplest solution is an external phantom power supply such as those available from Radio Design Labs. A more sophisticated solution, which addresses both the phantom power problem and the sometimes dubious quality of console mic pre-amps, is to consider an all-in-one mic pre-amp. Some support two microphones and range in price from about $100 per channel to well over $1,000 for a one-channel audiophile-quality tube rig. The most feature-rich family of external mic pre-amp designs incorporates multi-function processing (compression/expansion, de-essing, equalization, phase inverter, attenuation) with phantom power and a pre-amp for comprehensive mic control. At least one manufacturer offers a pre-amp with switchable digital AES/EBU or S/PDIF outputs.

Have condenser mics turned the broadcast market on its ear? Hardly. We're still using our old favorites because we like them and because our listeners like them. Do broadcasters have more options today than ever before? Absolutely. Are condensers coming? They're already here and their popularity will only grow.

Brian Sanders is a freelance audio consultant based in Mt. Baldy, CA.