THE SENSITIVE TYPE
Condenser (also known as capacitor) microphones come in two basic flavors: "true" condensers, for which the capacitor requires an externally applied electrical charge, and electret styles, which have a permanent charge already applied to the capacitor. Either way, the heart of a condenser mic is a complex, precision- manufactured diaphragm assembly (referred to as the capsule) that is an integral part of the microphone's electronics.
The sophistication of the condenser capsule and related circuitry offers numerous sonic advantages. These include hotter output level, increased dynamic range, extended and more accurate frequency response, lower noise, and richer sonic character. In addition, condensers are optimized to pick up very quiet and distant sounds, and they typically exhibit superb transient response (that is, a fast reaction time to the spiky, initial attacks of sounds, particularly percussive ones).
Premium condenser models typically offer multiple polar patterns (usually omnidirectional, figure-8, and one or more varieties of cardioid) as well as highpass filters and attenuation pads. A highpass filter (also known as a low- cut) decreases the low-bass response, and an attenuation pad reduces the output level. These various options, which can produce timbral changes ranging from drastic to barely perceptible, figure into the reputation that top condenser mics enjoy as versatile, high-performance recording tools.
Condenser microphones are usually more fragile and expensive than their dynamic cousins and can be very sensitive to popping and proximity effect when used on vocalists. Also, the increased sensitivity of a condenser mic, though advantageous in many situations, can be a drawback when having to contend with excess leakage, say in multiple-mic setups for ensemble recording. In addition, condenser microphones aren't just "plug and play"; rather, all types require a power source for the internal amplifier circuitry. Most contemporary solid-state condenser mics run on 48-volt phantom power, which is commonly supplied by mixing consoles or outboard gear. Tube condenser mics, on the other hand, have dedicated power supplies, and some electret condensers run on batteries.
Condenser microphones are generally favored by engineers for recording vocals, acoustic guitar, piano, woodwinds, strings, cymbals, percussion, mallet instruments, sound effects, ambience, and any source requiring lots of detail. Condensers are thus an essential ingredient in any classical and modern-jazz recording, and they are relied upon in all manner of pop music to put a bright, high-end sheen on sources. Professional stereo and live-concert recording is made possible by the use of carefully matched condenser pairs or dedicated stereo microphones.
There are many different kinds of condenser mics, each with its own uses and idiosyncrasies. We'll examine three more closely: small-diaphragm condensers, large-diaphragm condensers, and tube condenser mics.
SMALL, SMALL WORLD
All condenser mics use ultrathin, low-mass diaphragms, but those measuring 11/42-inch or less in diameter are in a class all their own. Highly prized for their superlative high-end and transient response, small- diaphragm condensers are often the first choice of engineers worldwide for use on drum sets (as overheads), hi-hat, percussion, acoustic guitar, mandolin, banjo, piano, classical ensembles, and more. However, the honesty and sharp treble emphasis of this design may be unflattering or lacking in warmth on some sources, and for this reason it is not a common choice for low saxophones, bowed bass and cello, male vocals, or distorted electric guitar.
The majority of small-diaphragm condenser mics are front address and single pattern, usually cardioid. But many of the major manufacturers offer modular systems with an assortment of interchangeable, single- pattern capsules with differing polar patterns. Other companies, such as Earthworks, have made their mark by producing very-small-diaphragm condenser mics that have the same accuracy and extended frequency response as scientific measurement microphones.
FEELING LARGE
Nothing gets the engineer's juices flowing quite like a large-diaphragm condenser. These are the fetish items of the recording world, renowned for their rich midrange, thunderous low-end response, creamy highs, and larger-than-life quality.
FIG. 3: Some manufacturers, such as Baltic Latvian Universal Electronics (BLUE), pull out all the stops for their top-of-the-line mics. The hand-built BLUE Bottle tube mic features eight interchangeable capsules, each with a different sonic “flavor,” to accommodate practically any application.
FIG. 3: Some manufacturers, such as Baltic Latvian Universal Electronics (BLUE), pull out all the stops for their top-of-the-line mics. The hand-built BLUE Bottle tube mic features eight interchangeable capsules, each with a different sonic “flavor,” to accommodate practically any application.
With the exception of a few models, all large-diaphragm condensers are side address, and their elegantly rounded grilles often afford a clear view of the 1-inch or larger capsule mounted inside. Since the advent of the home-recording boom, many no-frills models have come on the market, most offering only a fixed cardioid pattern, a basic mount, and (sometimes) a carrying case. For bigger budgets, the sky's the limit- your Rolls Royce large-diaphragm mic may be handmade and finished in 24-carat gold, with elaborate suspension mounting, custom-made screws and cables, and more (see Fig. 3). Whatever your tastes, the large-diaphragm mic is a must-have for recording lead and background vocals, saxophones and other reeds, and it's commonly used on low-end instruments such as acoustic bass, electric bass, jazz guitar, bass clarinet, hand drums, tom-toms, and bass drum.
TUBE JOB
All condenser mics made before the mid-1960s used vacuum tubes in their internal amplification circuitry. Yet despite the lower cost, convenience, and reliability of newer, solid-state transducers, vintage tube mics are more popular now than ever. In fact, large-diaphragm tube mics made by Neumann, AKG, and Telefunken in the 1950s and 1960s are responsible for the lush vocal sounds on many of today's big-budget pop productions. Renewed interest in these classic mic designs (not to mention skyrocketing prices) has spawned a new crop of large-diaphragm tube transducers that is within reach of the personal-studio owner.
In the digital-recording age, tube mics have become a hot commodity for home recording, especially on vocals. If it's accuracy you're after, look elsewhere. However, once you've tracked with a great tube mic, you'll understand why many engineers prefer these microphones for vocals, lead instruments, guitars, amplified keyboards, acoustic bass, and many other sources. The secret is in the tube itself, which adds subtle coloration, compression, and harmonic distortion to the sound.
Although large-diaphragm tube mics get most of the attention, small-diaphragm models are still plentiful and relatively affordable on the used market. In recent years, some of these have been retrofitted with new, large-diaphragm capsules made by Baltic Latvian Universal Electronics (BLUE), expanding their usefulness beyond their traditional duties as microphones for drum overheads, percussion, and stringed instruments. In addition, a new "medium-diaphragm" (31/44-inch) tube microphone is being marketed by GT Electronics (a division of Alesis).
IT DOESN'T STOP THERE
Though dynamic, ribbon, and condenser mics account for most of the music that gets recorded these days, other types are also available. One very useful (and popular) kind is the boundary effect microphone (the generic name for the PZM, or pressure zone microphone, trademarked by Crown), which is notable for capturing direct and reflected sound in phase. Other special types of mics include contact mics (the piezo electric, for example), which operate via direct vibrations from the instrument; crystal mics; and ceramic mics. These microphones are beyond the purview of this article, however.
AND THE WINNER IS...
Hopefully, this article has answered some of your questions about the different microphone types and what each does best. If you're like most of the folks I talk to, though, I'll bet that one big question is still unanswered. For most people, it goes something like this: "Mirror, mirror, on the wall, what's the best mic of them all?" Now, repeat after me: there is no single "best" microphone for any recording job. Some microphones do one thing very well, whereas others work well for a variety of applications. Moreover, it's easy to convince yourself that a particular mic sounds good on almost anything-especially if it's all you can afford.
Every musician is singular, as is every instrument, room, song, and so on. The combination of these elements yields a sonic result that is as unique-and irreproducible-as a snowflake. In your studio, on a given day with your equipment and knowledge, a microphone may sound very different than it would in my studio, or in the hands of Steve Albini, or on a Beatles record. What counts is that you know how to get the best results from the microphone at hand-and that those results sound right to you.