You may find yourself confused by all the technical terms in a microphone manual — unsure how each specification actually impacts performance. Take our upcoming PM-25 wired vocal microphone, for example: what makes it capable of smooth vocal reproduction, easy drivability, and handling high-SPL environments?
In this article, we’ll walk you through the most common microphone types and the key specifications worth knowing. By the end, we believe your confusion will turn into clarity.
A microphone is actually a transducer—it converts acoustic energy into electrical energy. As such, microphones are classified by how they perform this energy conversion. While there are many ways to convert sound into an electrical signal, we’ll focus on the two most popular types: dynamic and condenser.
Dynamic microphones consist of a diaphragm, voice coil, and magnet that form a sound-driven electrical generator. They operate on the following principle: as sound waves strike the diaphragm, the attached voice coil moves within the magnetic field, generating an electrical signal that mirrors the original sound waves.
This design brings several practical advantages. With lower sensitivity, dynamic mics can handle high sound pressure levels without distortion—making them ideal for live performances and loud environments. Due to their relatively simple construction, they are also more durable and reliable, with minimal maintenance required to ensure consistent performance.
Condenser microphone elements use a conductive diaphragm and an electrically charged backplate to form a sound-sensitive capacitor. They function on the following principle: As the diaphragm vibrates in response to sound waves, the distance between the mic and backplate fluctuates within the electrical field to create the signal. To process the signal, all condenser microphones include active electronic circuitry—commonly referred to as a preamp—which requires phantom power or a battery to operate.
Compared to dynamic microphones, condenser microphones have higher sensitivity and a wider frequency response, enabling them to capture more detail from the sound source. With these capabilities, they are well-suited for recording acoustic instruments and sampling sound effects.
Other types, such as ribbon or carbon microphones, also exist but are less commonly used due to their fragility, limited applications, or higher cost. Considering that most of our customers are performers, educators, and content creators who often work in live or mobile environments, the majority of Phenyx Pro microphones are dynamic models.
Frequency response refers to the range of frequencies a microphone can reproduce. Human hearing typically ranges from 20Hz to 20kHz, which is why many microphones have a frequency response that falls within this range. The frequency response is generally represented by a line graph, with frequency on the x-axis and output level on the y-axis. Bass frequencies range from 20Hz to around 300Hz, mid-frequencies cover 300Hz to 4kHz, and treble frequencies lie in the 4kHz to 20kHz range. By examining the response curve, you can identify which frequencies are accented or diminished, and select microphones for particular applications. The two most common types are flat response and shaped response.
A flat response microphone has equal sensitivity across all frequencies, without boosting or attenuating any specific range, so its response curve appears nearly horizontal on a graph. When recording acoustic instruments such as violins or pianos, a flat response microphone is preferred, as it allows for accurate reproduction of the original sound source.
Shaped response microphones boost or attenuate specific frequency ranges, creating a response curve with noticeable peaks and dips. This type of tuning suits various applications. For vocals, a microphone that reduces low frequencies and enhances the upper mids can help minimize proximity rumble and improve presence and clarity. In contrast, a kick drum microphone typically emphasizes low-end frequencies to produce a deeper, more powerful sound.
Microphone sensitivity is the amount of output voltage for a given sound pressure input. Microphone manufacturers typically use 1 Pa (Pascal), which is equal to 94 dB SPL, as a reference sound pressure. The resulting output voltage (measured in mV) under this condition is the sensitivity value, stated in mV/Pa. For easier comparison, this value can also be expressed in dBV. Due to the low output voltage of microphones relative to the 1V reference level used in dBV, the sensitivity value is typically negative. The closer the value is to 0, the higher the sensitivity—for example, -45 dBV indicates higher sensitivity than -50 dBV.
Condenser microphones typically feature higher sensitivity (-32 dBV to -38 dBV), making them very useful in low sound pressure level applications, such as recording dialogue or vocals.
Otherwise, dynamic microphones have lower sensitivity (–50 dBV to –60 dBV). One example is our newly released PM-25 dynamic vocal microphone. With a sensitivity of –50 dBV, it performs well in high sound pressure level applications like capturing guitar amps, drums, and more.
Impedance is mainly specified for wired microphones due to their direct connection to audio devices. Although wireless mics also have internal impedance, it is usually not disclosed or necessary for user consideration.
Impedance is the AC resistance to audio signal voltage and is measured in ohms. It can be divided into low (50–1,000 ohms), medium (5,000–15,000 ohms) and high (20,000+ ohms) impedance. There are usually two impedance specs: output impedance and input impedance.
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Output impedance is determined by the microphone. Most microphones are rated as low impedance (150~600Ω) for better compatibility with audio equipment such as mixers, preamplifiers, etc. Moreover, low-impedance microphones can support cable runs of nearly any practical length without noticeable sound degradation. In contrast, high-impedance microphones are limited in cable length—runs longer than about 20 feet can lead to high-frequency loss and a drop in output level.
Input impedance, also called load impedance, is determined by the connected audio device. To ensure proper signal transmission, the microphone’s output impedance must be appropriately bridged by the audio device’s input impedance—typically set to at least five times higher. So, if a microphone has an output impedance of 250 ohms, the preamp should have an input impedance of at least 1,250 ohms.
Polar pattern describes how sensitive a microphone is to sound coming from various directions or angles. You’ll usually see this represented by a polar pattern graph, which shows how the microphone’s sensitivity varies as you move 360 degrees around it. The three most common patterns are omnidirectional, unidirectional, and bidirectional.
Omnidirectional microphones pick up sound from all directions equally. With their ability to capture a natural and open sound, omnidirectional mics are a good choice for recording acoustic instruments, choirs, and other sources in well-controlled environments. However, due to their lack of directionality, they are less effective in rejecting background noise and suppressing feedback, making them unsuitable for live performances or other applications in acoustically complex environments.
Unidirectional microphones are most sensitive to sound arriving from one particular direction. The main unidirectional types include cardioid, supercardioid, and hypercardioid.
Cardioid is the most widely used directional polar pattern. This polar pattern is highly sensitive to the front (0 degrees) and less sensitive to the rear (180 degrees). Compared to omnidirectional types, it captures the singer's voice precisely while blocking out unwanted noise from the stage—an ideal for feature live performances and touring setups.
Supercardioid and hypercardioid pattens offer narrower front pickup angles than the cardioid – 115 degrees for the supercardioid and 105 degrees for the hypercardioid. They can provide more focused pickup than the cardioid pattern with better rejection of ambient noise and feedback. Even so, both patterns do pick up a bit from the rear, so you'll need to be careful with mic placement.
Bidirectional microphones, also known as figure-of-eight devices, pick up an equal level of sound from the front and the rear, but block out sound from the sides. In situations like interviews and duets, these microphones can be useful.
Max SPL is the maximum sound pressure level a microphone can handle without distorting. THD (Total Harmonic Distortion), is essentially a measure of how pure a signal is——it is the percentage of distortion present in the output signal. A threshold of 1% THD is commonly used because distortion below this level is inaudible to the human ear. Therefore, the Max SPL value listed in a microphone’s data sheet indicates the highest sound level the microphone can handle before reaching 1% THD, and it is expressed in dB SPL.
The most common cause of a distortion is the overloading of the microphone's electronic circuitry. Unlike a condenser microphone which has internal electronics that may overload, a dynamic microphone will not reach its distortion point due to its passive design, so max SPL is usually not listed in its specs.
As long as you're recording vocals, max SPL is rarely a concern. In contrast, you may run into trouble with certain percussion instruments like a tambourine or a drum. In that case, it’s recommended to use a microphone with a Max SPL of at least 135 dB SPL to avoid distortion.
Deciding the answer to this question can seem overwhelming, but it doesn't have to be. With industry standards from Shure, AKG, Audio Technica and Sennheiser, selecting a great microphone that will stand the test of time isn't hard to do. To help you decide whether it's the right time to go wireless or not, we've put together a guide to helping you navigate the wonderful world of being cable-less.
There are advantages and disadvantages to both wireless and wired microphone systems. Your choice should be determined by your specific application. It is very plausible that you would decide to go wireless just to reduce the trip hazards and unnecessary cabling on stage. That alone is a good reason, but let’s look a little deeper into the issue.
A wireless microphone will probably cost about four to 10 times as much as its wired counterpart. For example, the industry standard Shure SM58 hardwired microphone sells for $99.99 the same SM58 Capsule in Shure’s BLX24/SM58 wireless system sells for $399.99. This is Shure's entry level professional wireless microphone. This same microphone capsule in a Shure ULXD system can run into the thousands. When it comes to wireless, there are many things to consider. After asking yourself these questions, you will be much closer to making an educated decision.Questions to Ask When Making The Decision to go Wireless
Aside from freedom, which is the most notable advantage of a wireless microphone, there are many other great reasons to choose this option. Safety, aesthetics and sound quality. Yes, I said sound quality. As far as misconceptions go, there is one that surrounds wireless systems. Many believe that a wireless microphone can't sound as good as a hardwired one. This is simply untrue. Today’s digital wireless systems are incredibly accurate and reliable. You no longer need to be concerned about losing any of the sound quality you worked so hard to achieve.
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