You may be under the impression that a mic is a mic is a mic, right? They all pick up sound and convert it to electrical signals for recording or live sound. That’s true, but there are many different types of microphones that are suited to different situations and choosing the wrong mic for the job can ruin your performance. In this post I explain what the basic categories of microphone are, and some of the properties that various mics have in terms of pickup pattern and frequency response…
Mics are generally categorised into these 3 types: dynamic, condenser, ribbon.
These mics are usually your go-to mic for live use because they are often more solid and can take more of a beating than condenser or ribbon mics. This is true not only in terms of their construction, but also the amount of sound pressure they can take. You wouldn’t often find a snare drum miked with a ribbon mic.
Frequncy Response: Dynamic mics tend to have more of a focus on the mid range and capture sound at closer distances – IE they’re often less sensitive than other mic types. A common characteristic of dynamic mics, is the ‘proximity effect’ or ‘bass boost’. This means the closer a sound source is to the mic, the more the mic will emphasise the low frequencies. Dynamic mics usually feature a cardioid pickup pattern, which means the mic will pickup sound from mainly the front and sides but reject sound coming from the rear.
Uses: dynamic mics are often used live to mic drums, vocals, guitar amps/cabs, bass instruments and brass.
Common Dynamic Microphones: You’ll probably be familiar with the Shure SM57, & SM58 mics which are commonly used for instruments and vocals respectively. The ubiquitous AKG D112 is a dynamic mic designed for kick drums and can also be used miking bass cabs.
Condensers can be used in a wide range of situations, but are more commonly found in the studio than in live use due to their sensitivity. They are capable of recording sound sources with wide dynamic and frequency ranges well because of this. You may well find condensers used in live settings dependant on the kind of music being played. Their sensitivity can lead to a lot of microphone bleed – which means the mic will pickup more distant sounds that may be unwanted such as a drum kit or electric guitar. Because of this sensitivity, large diaphragm condenser mics are often used as room mics (to capture the ambient sound of a room, say for enhancing a drum kit) or in a situation where multiple audio sources need to be miked (like a group of vocalists or string instruments), although close miking is also an option, if you’re prepared to deal with mic bleed if there are multiple sound sources. Condensers come with either small or large diaphragm capsules and always use an external power source since they have internal amplifiers to boost the tiny signal generated by the capsule. Make sure your mixer has phantom power if you’re considering buying a condenser microphone (most do). Some electret condenser mics are battery powered. Condenser mics can range from a hundred pounds or so up to thousands. However, even in the cheaper end of the scale you can find some great quality mics. Condensers are omni-directional in their native state, but their pickup patterns can be manipulated which is why condensers often have switchable pickup patterns.
Frequency Response: Most condensers have a very wide frequency response and this makes them suitable for recording just about anything. One consideration would be the sound pressure levels as it’s easy to overload a condenser if things get too loud too close. A lot of mics therefore have a ‘pad’ switch which will lower the sensitivity. You’d still need to be careful that a mic doesn’t get bottomed out – when the diaphragm can stick to the backplate of the capsule from too-high SPLs (Sound Pressure Levels). Condensers have higher self noise than other mics dues to their built in amplifier, which can either be electronic FET or tube based. Most condensers will have a high frequency emphasis that can be great for detail. But just be careful you don’t add too much EQ in the upper frequencies later or things can start sounding edgy quite fast. If you’re thinking of doing stereo recordings with a pair of condensers, make sure you get a ‘matched pair’. Since no two condensers are exactly the same (even if they’re the same model) you don’t want to introduce phase or tonal differences when recording in stereo.
Uses: Distance miking, ensemble miking, studio vocals, drum room mics, drum overheads, acoustic instruments, electric guitar cabs.
Common Condenser Microphones: Neumann U 87, RODE NT1-A, Audio Technica 4050/4033, AKG C414, sE Electronics sE2200A, Sennheiser MD421/441.
The ribbon mic works in a similar way to a dynamic mic except it uses a very thin strip of aluminium foil (the ‘ribbon’) as a transducer. The electrical signal produced is tiny, though, so transformers are requires to boost the signal to a usable level. The mechanics and design are similar to that of a dynamic microphone’s moving coil, but a ribbon mic usually has a more extended upper range and a flatter response in general. Ribbon mics generally take EQing very well because of this. A ribbon mic doesn’t need phantom power to operate. However, although they can sometimes take very high SPLs, they are very delicate which makes them unsuitable choices for live use, and they need to be handled carefully. They are also moderately expensive to buy. Recently, ribbon mics have undergone something of a renaissance with modern designs making them smaller, lighter and more robust. Their new found popularity is for the same reasons they were always prized – their flat frequency characteristics, and phase linearity. Ribbon mics mostly have a figure 8 pickup pattern. This and their inherent fragility make them largely unsuitable to live use, so you’ll mostly find ribbon mics in the studio.
Frequency Response: Usually fairly flat and smooth. If there’s an emphasised area, it’s the warm low-mids. A roll off in treble frequencies above 14KHz. Ribbons take to EQ very well. Ribbon mics are comparable to the warmth and romance of vinyl vs the clarity and detail of condensers as the CD.
Uses: Mainly studio work – Drum overheads, brass, vocals, acoustic instruments, electric guitar cabs. Large Ribbons have a great reach and can pickup sound from a distance and still make it sound warm and rich. The slightly darker sound makes these mics unsuitable for trying to get something to punch or cut through the mix. Good on shrill sources to tame the highs.
Common Ribbon Microphones: Coles 4038, Royer R121, Beyer M160, AEA R44 and A440, Sontronics Sigma, Audio Technica 4080, sE Electronics R1.
Omni-directional – Picks up equally in all directions
Sub-cardioid – Picks up mainly at the front and sides, a little from the rear.
Cardioid – Picks up predominantly from the front, then sides, rejects well at the rear.
Super / Hyper-Cardioid – Picks up strongly at the front, rejects more at the sides. rejects largely at the rear, but has a small bubble of pickup area at the rear. Quite directional.
Figure 8 / bi-directional – Picks up in a figure 8 pattern. Rejects at the sides of the 8 very well.