For voice actors, a microphone is undeniably the most important voice over tool since their success in the voice over industry depends widely on it. While the microphone has been with us for well over a century, it has evolved drastically from its crude beginnings. A microphone is a device for converting acoustic power into electric power with essentially similar wave characteristics. It converts sound waves into electrical voltages that are subsequently converted back into sound waves and amplified through speakers.
While some microphones have remained almost identical over time, such as several old standards from Shure and Neumann, others have advanced to handle higher levels of sound pressure to be used for live sound production as well as with acoustics.
Voyzapp - the largest online voice over marketplace, presents this definitive guide about microphones that spans across history of different microphone types, Glossary of microphone terminology and the best microphone available in the market today. Let’s take a look at what’s well worth the investment for you
History of Microphones
- Early Inventions: While the word “microphone” wasn’t used until the 19th century, English physicist and inventor Robert Hooke is credited with developing an acoustic cup and string style phone in 1665 and is considered a pioneer in the field of transmitting sound across distances.
The German inventor Johann Philipp Reis built the "Reis telephone" in1861, that used a metallic strip attached to a vibrating membrane to produce intermittent current.
The US inventor, Alexander Graham Bell, invented the "liquid transmitter" in 1876. It was a rudimentary liquid contraption that used voice vibrations to rattle a needle in water and was the first of its kind design.
- Carbon Microphones (1886) :The history of carbon microphones goes back to the 19th century when David Edward Hughes in England and Emile Berliner and Thomas Edison in the US fabricated one of the first carbon mics in the 1870s. While Thomas Edison and Emile Berliner fought over patent rights for perfecting the design around the same time, Hughes tends to get the nod as the inventor of carbon microphone technology as he had demonstrated his working device in front of many witnesses some years earlier. Hughes also coined the word ‘microphone’, but never sought a patent, preferring to share the technology with the world. The carbon microphone was the first reliable form of microphone and it was widely used for many years before being supplanted by other types that gave much higher levels of performance.
The Operating Principle: All microphone cartridges, regardless of type - are transducers that convert sound waves into electrical energy. The carbon microphone depends for its operation on the varying resistance of a carbon element when subjected to varying pressure. The basic concept behind the carbon microphone is the fact that when carbon granules are compressed their resistance decreases. This occurs because the granules come into better contact with each other when they are pushed together by the higher pressure. The usual arrangement of this type unit, for best fidelity, consists of two carbon buttons one on either side of the diaphragm. This metal diaphragm - in a properly built carbon microphone - is stretched and air damped so that the effects of self-resonance vibrations are negligible, giving a reasonably uniform output at all ordinary audio frequencies.
Simply stated, anthracite coal (carbon) granules are contained within a small half-sphere covered with a thin metal diaphragm. External power is applied to generate a current flow through the microphone. Sound waves strike the microphone diaphragm causing it to vibrate, exerting varying pressure onto the carbon granules. These varying pressure levels translate into varying levels of resistance, which in turn vary the electrical current passing through the microphone. It’s a simple concept resulting in a rugged and reliable, if somewhat noisy, microphone.
Carbon microphones were an ideal choice of microphone in the early days of the telephone. They were widely used in telephone applications because they gave a high output which meant no amplification was used. As radio started, the carbon microphone was initially used there as well – for broadcasting as well as for professional radio voice over in English or communicating in any other language. The use of the carbon microphone persisted for many years for communications purposes as they gave a high output and they were robust. However their use in broadcast applications soon came to end because of the drawbacks of noise and poor frequency response. Other types of microphone started to become available and their use was preferred because of the better fidelity that was available.
- Condenser Microphones (1916): In 1916, the condenser microphone was developed by E. C. Wente of Bell Laboratories. Early models of the mics were not reliable, and they were held aside mostly for acoustic research. The German company, Georg Neumann and Co., designed the first condenser mic for commercial use. They called it the ‘Neumann bottle’ due to its shape. By the mid-twenties, improved condenser models began appearing, and by the late twenties, Western Electric had produced six different models of condenser mics
The Operating Principle: Like its predecessor (the carbon microphone), the condenser microphone utilized two plates. However, the condenser microphone did not include any carbon granules and rather had an empty space between the plates. The two plates of the condenser microphone formed a capacitor (then referred to as a “condenser,” hence the name). A consistent voltage was applied across the plate to hold a fixed charge. One of the plates, as had been done with the carbon microphone, was very thin and acted as a diaphragm, moving in sympathy with the sound waves that hit it. The other plate (the backplate) was thicker and stationary. As the diaphragm moved, the distance between the plates changed which altered the capacitance of the parallel-plate capacitor. By maintaining a fixed charge across the plates, any change in capacitance caused an inversely proportional change in voltage. Therefore, the moving diaphragm caused a coinciding AC voltage (mic signal) to be outputted from the mic. The condenser microphone required an amplifier built within the microphone to pick up the faint signals. Condenser microphones were used for radio broadcasting and the first generation of sound motion pictures.
- Ribbon Microphone (1924): The German physicist Walter Hans Schottky and Dr. Erwin Gerlach co-invented the ribbon microphone in 1924. A few years later, Dr. Harry F. Olson of RCA started developing ribbon microphones using ﬁeld coils and permanent magnets.
The RCA Ribbon Microphone Photophone Type PB-31 was commercially manufactured in 1931, greatly impacting the quality voice over recording services and the broadcasting industries.
The Operating Principle: The idea behind the ribbon microphone was that a very fine conductive ribbon could be suspended within a magnetic field and produce an electric signal as it moved within this field. The so-called “ribbon” was an ultra-thin strip of material, typically aluminum, held (suspended) into position by two powerful magnets. The ribbon, in this case, acted as the diaphragm, moving in sympathy with the sound waves that hit it. As the conductive ribbon moved, it generated an AC voltage (an audio signal), making it a simple yet ingenious design.
Ribbon microphones were at the forefront of broadcasting from the 1930s through to the 1960s. They went out of favor for a while as other technologies came into being. Their demise had less to do with sound quality and more to do with the fragility of ribbon mics, which limited their usage. However, recent improvements have given rebirth to this old technology. The sound produced by today’s ribbon microphones is close to that of what the human ear catches. The clear, warm, natural sound makes them the perfect choice for guitar cabinets, drums, and vocals. Improvements to the strength of these otherwise delicate mics are why they’re making a strong comeback.
- Dynamic Microphone (1931): In early 1931, Western Electric marketed its 618 electrodynamic transmitter—the first dynamic microphone. The moving-coil idea had been around since the late 1800s, but the vacuum tube amplifier and the cobalt permanent magnet material combined to make it a reality. In an audio world populated with noisy carbons and largely troublesome condensers, both of which required power supplies to operate, the 618’s claim of a small, trouble free microphone was an instant success. In the mid-thirties, Western updated the concept with the classically designed 630A “8 Ball.”
The Operating Principle: In a dynamic microphone sound waves hit a thin metallic diaphragm that is attached to a coil of wire. The diaphragm vibrates the coil in response to the sound wave. A magnet that is positioned inside the coil produces a magnetic field. It is the motion of the coil in the magnetic field which generates the electrical signal corresponding to the sound picked up.
The motion of the diaphragm within the microphone produces a current. The amount of current is determined by the speed of the motion. For this reason, dynamic microphones are known as being velocity-sensitive.
- Other Developments: After World War II ended, the production of microphones began to pick up. Thereafter the vintage microphone, Shure Model 55 became a regular site in music circles from 1939. The smaller version, Model Super 55, was affectionately named the Elvis Presley Mic. Up to that time, attaining anything other than an omnidirectional pattern meant using more than one diaphragm and combining their outputs. This resulted in a large mic head that usually didn’t sound all that good because the elements were spaced apart and usually had different frequency responses. Shure developed the mic element in the 1930s, using small ports that allowed sound waves to reach both sides of a diaphragm at different times, resulting in a more linear frequency response. It was breakthrough technology that used a single dynamic element to achieve pattern control. The element of the Model 55 was also suspended on springs dampened with foam to isolate the diaphragm from handling noise.The combination of great sound, compact size, cardioid pattern and classic styling made the Model 55 an instant hit. As the world’s first single-element directional mic with a cardioid polar pattern, the Shure Model 55 has become the most iconic model of all time. Modern versions of it continue to sell well to this day.
In 1957, Raymond A. Litke invented and filed a patent for the first wireless microphone. It was designed for multimedia applications including television, radio, and higher education.
The Unidyne III microphone was the first unidirectional device designed to collect sound from the top of the microphone, rather than the side. Invented in 1959, this model set a new level of design for microphones in the future, helping voice actors to provide quality voice over and expert dubbing services in multiple languages.
Afterwards, Bell Laboratories researchers James West and Gerhard Sessler received a patent in 1964 for the electroacoustic transducer, an electret microphone. The electret microphone offered greater reliability and higher precision at a lower cost and with a smaller size. It revolutionized the microphone industry, with almost one billion units manufactured each year.
In the 1990s, Neumann introduced the KMS 105, a condenser model designed for live performances, setting a new standard for quality.
- Modern developments: The 2000s saw MEMS (Microelectromechanical systems) microphones used in portable devices including cell phones, headsets, and laptops.
The Eigenmike was released in 2010, composed of several high-quality microphones arranged on the surface of a solid sphere, allowing the sound to be captured from a variety of directions. This allowed for greater control when editing and rendering sound.
Thanks to all the development, the four main types of consumer-friendly microphones available today are:
- Dynamic mics
- Condenser microphones with large diaphragms
- Condenser microphone with small diaphragms
- Ribbon microphones
When Experienced Voice Over talent for Animation or Audiobook are learning to properly use microphones, they need to simultaneously learn the lingo that other voice artists, sound engineers and audio directors use when referring to the tools of their trade. Here are some of the most common terms associated with microphones:
- Acceptance Angle: Also known as coverage angle or pickup angle, it is the angle between the two points on its polar pattern where its sensitivity drops 3 decibels compared to its on-axis response. Smaller angles yield more focused captures in the area the mic is pointing due to stronger off-axis rejection.
- Alternating Current (AC): Alternating Current (AC) is an electrical current that periodically reverses direction. Mic signals are AC, alternating between negative and positive current and voltage.
- Ampere (Amp): An ampere (amp) is the SI unit of electrical current (symbol: A). It is a measurement of the rate of flow of electrons (negative charge). One ampere is equal to a flow of one coulomb per second. A microphone signal is an electrical AC signal that is outputted from a microphone. It is an electrical representation of the acoustic energy converted by the mic’s capsule.
- Amplifier: A device that tracks the amplitude of an incoming signal and proportionally increases the voltage, current or power of the signal by adding power from another source.
- Attenuation: The process of decreasing the amplitude of a signal as it passes from one point to another. Analog attenuation circuits typically use resistors to reduce the voltage of a signal. In audio, the effect of such attenuators is usually expressed in decibels.
- Balanced line: An audio line comprising three conductors—two carrying signals and a ground (shield) wire, where one of the signal wires carries the sound and the other carries an inverted copy. When the signal reaches the destination, the inverted copy is flipped and added to the original. Any noise that has been induced into the signal is also inverted. When this is combined with the “uninverted” noise, it cancels it out. Balanced lines thus are less susceptible to hum and can carry audio signals over longer distances.
- Capacitor microphone: An alternate, less-used term for condenser microphone.
- Condenser microphone: A microphone that picks up sounds via an electrically charged, metallized diaphragm, which is separated from a conductive back plate by a thin air layer. Sound waves striking the diaphragm cause a minuscule voltage change, which is increased by a tiny amplifier circuit within the mic body. Because power is required by both the microphone capsule and the amplifier, condenser microphones must have a power source, which can be a battery inside the mic body or “phantom” power from a mixing console or external power supply.
- Used by professional voice over actors/artists, ideal for recording vocals or acoustic guitars
- Perfect for precision recording and capturing subtle nuances
- They do need a power supply
- Very sensitive to breathing and “popping”
- Harder to use without practice
- Fragile, can be damaged by moisture and dust.
- Decibel: A unit of measure used to logarithmically express ratios of change in power or signal levels. Equal to one-tenth of a Bel (named for Alexander Graham Bell).
- Dynamic microphone: A transducer that relies on the law of induction, with an output proportional to the velocity of a moving element within a magnetic field. The most common type is the moving-coil microphone, which picks up sounds when sound waves strike a diaphragm attached to a coil of wire. When the coil moves within the magnetic structure of the microphone, it creates an output voltage. The process is exactly the reverse of the way a speaker operates. Moving-coil dynamic microphones tend to be extremely rugged, making them well-suited for most sound reinforcement applications.
- The Dynamic Microphone is a good all rounder microphone which can be used for vocals, recording drums as well as guitar amps
- It does not need a power supply
- They are fairly low cost
- Most common types are the Shure SM57 and the Shure SM58
- Dynamic range: A ratio (expressed in dBs) of the difference between the softest and the loudest sound that can be produced, reproduced or captured by a musical instrument or audio device.
- Feedback: A condition where the output of a circuit recycles through its input. Acoustic feedback is a whine or howl that occurs in live audio situations when an amplified sound re-enters a sound system through the same microphone (or guitar pickup) that reproduced the original source, creating a loop.
- High Pass filter: A circuit designed to attenuate, or cut, frequencies that fall below some designated point, while allowing higher frequencies to pass unaffected.
- Impedance: Measured in ohms, this is a way of expressing a circuit’s opposition (resistance and reactance) to a signal or current attempting to pass through. The practical difference between impedance and resistance is that impedance changes as a function of frequency.
- Phantom power: A method of powering condenser microphones by sending DC current (typically 9 to 52 volts) over the same mic cable that carries the audio signal. “Phantom” is derived from the fact that there is no visible power cord and the voltage is not perceptible in the audio path.
- Polar pattern: A circular, 2-D plot that indicates the directional response of a transducer. While polar patterns are commonly used to show microphone pickup patterns, they can also indicate the dispersion of a speaker. Interpreting polar patterns, even with something as simple as a common cardioid microphone, can be fairly complex. For one, the polar response shown on paper doesn’t indicate the fact that a microphone’s pickup pattern is actually a 3-D space around the mic. Second, the polar response of any microphone is frequency-dependent. For example, an ultra directional “shotgun” microphone is extremely directional at high frequencies and much less so at low frequencies.
- Cardioid Microphones
Cardioid mics capture sound from the front and reject everything else from the rear and sides. This front-focused pattern allows you to point the mic to a sound source and isolate it from unwanted ambient sound, making it ideal for live performance and other situations where noise reduction and feedback suppression are needed. Cardioid mics are the most common type used for a wide variety of applications from live performances to miking instruments. Be aware that these types of mics add subtle sound coloration in bass frequencies when the sound source is close, so mic position is important.
- Supercardioid and Hypercardioid Microphones
These two types of mics are more directional than cardioid and have a narrower area of sensitivity. These mics provide improved isolation and higher resistance to feedback. Their enhanced ability to reject noise makes them ideal to use for loud sound sources, noisy stage environments or even for untreated recording rooms. However, these polar patterns have sensitive rear lobes making them difficult to position when trying to reject unwanted sounds like stage monitors and drum kits.
- Omnidirectional Microphones
Omnidirectional microphones capture sound equally from all directions. This type of mic has a more natural sound because of their non-directional design that eliminates any rejection. Omnis are excellent for capturing room sound in studios and other venues with great acoustics and are generally used for high quality TV and Radio Advertisement voice over. They can also be used for recording multiple instruments, as long as the noise level is low. However, the downside is that they lack background noise rejection and are prone to monitor feedback, which makes them unsuitable for loud and noisy spaces.
- Figure-8 Microphones
Figure-8 mics capture sound from both the front and back but reject sounds coming from the sides. This type of mic produces a polar pattern that looks like a “figure-8.” This pattern is also known as bi-directional. The front and back sensitivity make them ideal for stereo recording or for capturing multiple instruments.
- Shotgun Microphones
Shotgun mics have a very narrow and extended polar pattern that is even more directional than hyper cardioids. They feature a tube like design that has a longer pickup range. These types of mics are often used for broadcasts such as sporting events because they excel at isolating sounds in higher noise environments from a distance. They are also used as overhead mics for capturing sounds in a room. However, shotgun mics often have very poor sound quality.
- Switchable/Multi-Pattern Microphones
Multiple pattern microphones allow you to switch between different polar patterns. Many of today’s USB condenser microphones have a feature that provides the option to select a polar pattern that meets your needs with a simple flick of a switch. Other types provide the same flexibility through changing the mic head. These mics offer more positioning possibilities and more usage.
- Proximity effect
A boost in the low-frequency response of a directional microphone that occurs when the sound source is relatively close to the microphone. The phenomenon begins when the source is about two feet away from the mic capsule and becomes more noticeable as the subject gets closer to the mic. Used properly, a voice artist can use the proximity effect as a means of adding fullness to a voice; however, the effect can also emphasize non desirable low-frequency noises such as breath sounds and popping consonants (“p” and “b” sounds).
Different mics handle proximity differently. As a general rule of thumb, the more directional a mic, the more pronounced the proximity effect will be. Ribbon microphones have the most pronounced effect and Cardioids are next in line. Omni-directional microphones exhibit no proximity effect at all. Anything with a variable polar pattern will be subject to this reality: the closer to omni you go, the less proximity effect — the tighter the polar pattern, the greater proximity effect.
- Ribbon microphone: A type of dynamic microphone that uses a thin metal ribbon placed between the poles of a magnet. Ribbon mics are typically bidirectional, meaning they pick up sounds equally well from either side of the mic. Ribbon mics are for the recording professionals who want a vintage sounding vibe to their recording. Ribbon mics have an uncanny ability to record higher notes in the voice and relay more ambient sounds. These features also make these microphones very popular with those who want to record a wide range of acoustic instruments professionally.
- Extremely sensitive microphone
- Great for vocals, choirs, piano and strings
- Perfect for recording multi-instruments in a room
- Often described as a more vintage vibe
- Can be quite expensive
- Roll-off filter:A circuit that attenuates a signal that is above (low pass filter) or below (high pass filter) a specified frequency. For example, microphones frequently have a bass roll-off filter to remove wind noise and/or excessive breath pops.
- Spaced pair: A stereo microphone technique where two microphones are pointed directly at the source separated by two feet or more. Depending on the mic-to-source distance, this method can provide an extremely wide (occasionally exaggerated) stereo perspective.
- Transducer: A device that transforms energy from one form to another. Examples of electromechanical transducers include microphones (which convert acoustic pressure into electrical voltage) and loudspeakers (which convert voltages into acoustic pressure).
- Unbalanced: A circuit that carries information by means of one signal on a single conductor. Unbalanced cable usually consists of a single conductor and a shield as in instrument cables, coaxial cable, patch cords, and high impedance mic cable.
- Volt :Named in honor of the Lombard physicist Alessandro Volta (1745–1827) the volt is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power.
- XLR: Developed by ITT/Cannon, XLRs are rugged, locking multi pin connectors frequently used in professional audio equipment. While 3-pin XLRs are most commonly seen on microphones and console inputs, other configurations also exist, such as 4-pin XLRs (a standard for stage intercom systems) and 5-pin XLRs (often used on stereo microphones).
- X-Y miking: a stereo microphone technique where two directional mics (typically cardioid) cross at an angle from 90° to 130°, with their capsules placed closely together.
Popular Microphones in the market today
Finding a microphone that will highlight your talent as a voice actor, and bring confidence to your recording can be a bit of a challenge. The market is flooded with varying vocal microphones, and everyone has an opinion on which ones are the best. Your microphone has one of your studio's most important roles: It is the connection between you and what your clients hear and therefore it is important to do an extensive search for the right microphone for voice overs. While there are many factors to consider when purchasing a microphone, such as your budget, the sound you are trying to achieve and the space you will be recording, here is a comprehensive list of the best voice over microphones available in the market today.
- Rode NT1A
- Frequency Range: 20Hz - 20kHz
- Polar Pattern: Cardioid.
- Connector: XLR cable
- Extended dynamic range and high sound-pressure level tolerance
- Higher-quality build ensures quality and better conversion
- Neumann TLM103
- Polar Pattern: Cardioid.
- Frequency Response: 20Hz-20kHz.
- Connector: XLR
- Natural sound
- Popular among pro audio enthusiasts
- Low self-noise
- Flat frequency response
- Blue 1967 Yeti Pro
- Power Required/Consumption: 5V 500mA (USB)/48V DC (analog)
- Polar Patterns: Cardioid, Bidirectional, Omnidirectional, Stereo.
- Frequency Response: 20Hz – 20kHz.
- Easy to use
- Crisp, transparent and dynamic sound quality
- Comes with its own stand mount and custom base that provides adequate stability.
- Has an attractive ergonomic design
- Not capable of handling both digital and analog operations simultaneously
- Samson Meteor
- Frequency Range: 20 Hz to 20 kHz
- Polar Pattern: Cardioid.
- Connector: USB cable
- Large diaphragms for natural sounds.
- Almost zero noise
- Little heavy
- Shure SM7B
- Polar Pattern: Cardioid.
- Frequency Response: 50Hz-20kHz.
- Connector: XLR.
- Flat frequency
- Good sound isolation
- Value for money
- Little less gain
- Audio-Technica ATR2100
- Polar Pattern: Cardioid.
- Frequency Response: 50 – 15,000 Hz.
- Power Requirements: USB Power (5V DC)
- Connector: USB and XLR
- Effectively blocks background noise
- For good quality sound, you’ve to speak closer to the mic.
- EV RE20 Studio Microphone
- Polar Pattern: Cardioid
- Frequency Range: 45 Hz to 18 kHz
- Output Connectors: XLR 3-Pin
- Great sound quality
- Built-in pop filter
- Highly durable
- Low self-noise
- Avantone Pro CV-12
- Frequency Range: 25Hz-20kHz
- Polar Pattern: Cardioid, Omni, Figure-8
- Connector: Male XLR 7 pin w/ special power supply and cables
- Excellent, sturdy construction
- Offers clearest, most digital-sounding audio
- RF interferences may be experienced
- MXL 770
- Frequency Range: 30Hz - 20kHz
- Polar Pattern: Cardioid.
- Connector: XLR cable
- Budget-friendly condenser microphone
- Low frequency roll-off to reduce unwanted rumble
- Background noise isolation is not 100%
- Blue Snowball iCE
- Frequency Range: 40 –18 kHz
- Polar Pattern: Cardioid.
- Connector: USB
- Sleek size and versatile
- Audio quality not as high as the others, but still feasible
As a voice actor, your microphone is the linchpin of all your equipment and your best friend in your lifelong career as a voice actor. Despite the magic an audio editing software can do, the quality of your microphone plays the biggest role in determining the overall quality of your voice over recordings. For this ultimate reason, it’s important to know the basic terminologies and do a thorough research before purchasing the microphone. Give yourself time to test out different microphones in the space you will be recording your voice overs. Nothing can replace the experience of actually testing several microphones and listening to the myriad of choices and sounds that different microphones offer. It is truly an ear opening experience.
If you want to become a successful voice actor and are looking to ace in the voice over industry, you must know the technique to record like a pro. Understanding which type of microphone works for your voice and taking the proper steps before you hit the record button will go a long way to ensuring your voice overs sound professional and engaging!