This series, Tools of the Audio Trade by Matt Boudreau, is designed to help podcasters boost their audio skills from intermediate to advanced. Browse the index below for the full series.

Audio InterfacesAudio Cables | Signal to Noise | Microphones | Equalizers (EQ)

Searching for a new microphone can be a daunting task. The style and quality of microphones differs greatly, and the old standby that you get what you pay for isn’t necessarily true anymore. With great quality microphones available across the price spectrum, cost is no longer a reliable characteristic in determining a microphone’s quality. So what qualities should podcasters and producers be looking for in a microphone?

What is the Transducer Type? Dynamic vs Condenser

Microphones are a form of transducer. That is to say that microphones convert energy from one form (acoustic or kinetic energy) to another (electrical energy). There are three transducer types commonly associated with microphones: dynamic, condenser, and ribbon transducers. However, for most vocal applications dynamic and condenser microphones are used. Ribbon microphones, while excellent in quality for sound reproduction, tend to be very expensive and extremely delicate.

Dynamic

Dynamic microphones operate by suspending a coil of wire connected to a diaphragm inside a magnetic field. When sound vibrates the diaphragm, the coil vibrates and produces an electrical signal.

Characteristics

  • durable
  • handle heat and humidity well
  • high volumes without distortion
  • rougher, but usable, audio signal

Applications

Dynamic microphones are good for general vocals that don’t necessarily need accurate and smooth reproduction, such as interviews, hosting, and live venues.

Due to the rougher sound characteristics, dynamic microphones with a cardioid pattern tend to eliminate more background noise, although they may lose some nuances in a performance. This makes them well-suited to podcast hosting, general voice recording, and recording voices outdoors for voiceover or interviews. They are also suitable for recording very loud items, such as drums, guns, and explosions.

Condenser

Condenser microphones operate by vibrating a conductive diaphragm against a charged backplate to convert acoustic energy to electrical energy.

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Characteristics

  • smooth frequency response
  • clear, detailed sound with crisper highs
  • excellent low-frequency response
  • not suited to extremely hot or humid environments

Applications

Condenser microphones are good for most studio applications, including voice acting. They produce a clarity of voice while giving it both warmth and presence.

Condenser microphones are the industry standard for voice actors. The Neumman U47 (pronounced NOY-man for you lubbers) is iconic and has defined the sound that the voiceover industry and producers look for. If you have around $4000 to spend on one microphone, I highly recommend it. For the rest of us, there are comparable mics that offer exceptional quality.

Condenser microphones are also excellent for field recording, as they are more sensitive than dynamic microphones and have a flatter response that is suited to capturing detailed audio.

Polar Patterns

Polar patterns illustrate how a microphone reacts to sounds coming from different directions. There are several polar pattern types, but our main focus for vocal microphones is on omni and cardioid polar patterns.

Omni

OmnidirectionalAn omnidirectional microphone receives sound with equal sensitivity from all directions. This means that audio coming from the rear and to the sides of the microphone will be picked up with equal volume and clarity.

Characteristics

  • pick up of room reverberation
  • extended low-frequency response
  • lower cost

Applications

Omni microphones are good for recording situations where sound isolation is not needed or wanted. They are particularly useful for interviews and situations where more than one vocal needs to be recorded but sound isolation is not a factor.

Cardioid

Cardioid microphones are most sensitive at the front of the microphone, typically about 6dB less sensitive to the sides, and around 20dB less sensitive to the rear of the microphone.

Characteristics

  • less reverb pickup than omni
  • less room noise pickup than omni
  • minimises off-axis pickup

Applications

Cardioid microphones are ideal vocal microphones for one-voice-one-microphone applications. Voice actors and show hosts benefit from off-axis pickup reduction focusing the sound on what matters most: the speaker’s voice. The majority of studio-based professional audio requires unidirectional microphones (cardioid, hypercardioid, or supercardioid). Voice actors and podcast hosts (and vocalists!) are likely to find that microphones with a cardioid polar pattern will suit their needs best. Hypercardioid and supercardioid mics work well, too, depending on your voice and application. However, they tend to be more expensive and lack the warmth that a large-diaphragm cardioid delivers to more resonant male and female voices.

Frequency Response

Frequency response refers to the range of frequencies your microphone can accurately reproduce at an equal level. Understanding frequency response is one of your best tools when researching audio gear.

Simply put, frequency response show how a microphone affects the way your voice sounds. In general, when looking at a frequency response graph, you want the graph to be as flat at possible in the frequencies the microphone is being used to produce. In terms of voice, we are most concerned with the frequencies between 80Hz and 12kHz: the human vocal range.

Some microphones will have slight peaks in the 5–12kHz range to improve presence, or some lift in the 500–800 Hz range to improve warmth. These characteristics can be desirable, depending on your production and scope.

In order to reduce low-frequency rumble and high-frequency hiss, microphones that roll off below 80Hz (high pass) and above 12kHz (low pass) are best suited for voice. This is especially helpful in cutting down on noise from vehicles and HVAC systems. However, this can also be accomplished by using an EQ highpass and lowpass to filter out these frequencies.

Other Factors

Here are some other factors to consider when researching and purchasing a microphone.

Impedance

Impedance is a measure of a microphone’s resistance. Higher resistance in a microphone introduces hum and reduces high frequencies, making the recording sound noisy, or thin. Low-impedance, or low-Z, microphones allow long mic cable runs without introducing noise or reducing frequencies.

Sound Pressure Levels (SPL)

Sound pressure levels indicate the maximum sound intensity a microphone can handle before distorting. In general, a spec of 120dB or greater is preferable. For podcasters miking loud instruments, such as brass or drums, microphones with a higher maximum SPL are best.

Equivalent Noise Level

Also known as self-noise, the equivalent noise level is the electrical noise or hiss a microphone produces. In general, a self-noise specification of 28dB and lower is acceptable for quality recording.

Signal to Noise Ratio (S/N)

This is the difference (in dB) between a microphone’s sensitivity and the equivalent noise level. 64dB and higher is good.

Recommendations

There is a lot of subjectivity in determining the best microphone for an individual’s use. The biggest determining factor tends to be price range. At minimum, the best microphone for the job is the microphone that best captures (or enhances) the frequencies of the sound source as accurately as possible, with the lowest amount of noise, within your price range. Here’s what to look out for depending on your recording purposes:

The Podcast Host:
Large-diaphragm dynamic or condenser
Cardioid polar pattern

A large-diaphragm microphone allows room for warmth to deliver that ‘broadcast host’ sound. Whether to use a dynamic or condenser is largely a matter of taste. However, if you are in a particularly noisy environment, a dynamic microphone is typically less sensitive and will pick up less noise.

Voice Actor:
Large-diaphragm condenser
Cardioid polar pattern

For the voice actor, a condenser mic is the industry standard for its high sensitivity, which captures nuances in the voice and clarity in the articulator frequencies (frequencies associated with sounds made by the lips, teeth, tip of the tongue, and soft palate, including most consonant sounds). Condenser microphones deliver a warm, smooth sound that captures the presence of the actor.

This series, Tools of the Audio Trade by Matt Boudreau, is designed to help podcasters boost their audio skills from intermediate to advanced. Browse the index below for the full series.

Audio InterfacesAudio Cables | Signal to Noise | Microphones | Equalizers (EQ)