The world has many types of microphones. It would be best to start from the basics to understand and use the microphone for work and life.
The microphone is a part that greatly affects the quality of audio, video, and music. A properly used microphone will greatly contribute to creating great sound.
If you are an amateur or even someone who often has to use the microphone but still does not know the best way to use the mic effectively.
Don’t worry. This article will give you complete knowledge of how to use a microphone. Gives you an overview of how to use the microphone correctly and conveniently.
The Main Types of Microphones
You’ll find both long and shortlists of microphone types if you search for them. There will also be many that differ from each other.
There are many types of microphones available, including shotgun mics and boundary mics. Ribbon mics are also common. However, most hobbyists and recording engineers only use the two below types.
The dynamic mics you will see most often on stage have the sound directed down the front of it. They can handle louder sounds because they are less sensitive to volume and damage.
The diaphragm vibrates when sound pressures are applied to it. In dynamic mics, it moves a magnet through the magnetic field of a wire coil. This allows electricity to flow.
This entire system is known as a transducer. It works differently in a condenser microphone, which is what makes them unique.
These mics are what you will find in recording studios. These mics are aimed directly at the sound source.
They can sense subtle changes in volume and are sensitive to small changes. This is why they are preferred in studios where the acoustic environment has been tightly controlled.
However, you could damage the tube or larger diaphragm if you record too loud or drop it. The transducer allows the diaphragm to vibrate closer to a charged metal plate.
This is why condenser microphones require Phantom power or another external power source such as a battery or power supply.
How To Use A Microphone
The 4 key actions to use a microphone are, in simple terms:
These four steps will enable you to use any microphone or at least how to use it. These are the four steps that this article will concentrate on.
Connecting A Microphone To A Mic Input
A microphone can technically be used by itself, but it is best to connect it with a device that will use its output signal.
This connection is always made via a microphone input. Although microphones can technically be connected to any audio input provided they have the correct connectors, this article will focus on mic inputs.
There are many devices that microphones can connect to, including:
- Preamps for microphones
- Mixing boards
- Audio recorders.
- Audio interfaces.
- In-line devices (pads, high-pass filters, phantom power
supplies, RFI filters, etc.
- Cell phones
Connectors for microphones are used to connect to the above devices include:
- XLR (3-pin or 5-pin), 7-pin, or another variant
- TS (2.5mm or 3.5mm (1/8 ”),, 1/4”).
- TRS (2.5mm or 3.5mm (1/8 ”),, 1/4”).
- TRRS (2.5mm and 3.5mm (1/8 ”),, or 1/4”).
- TA3 (mini XLR)
- Tube PS
Most mic inputs can be described as mic preamplifiers. These provide the required gain to increase the mic level signal to line-level. This is covered in the Preamp Gain and Using Microphones with Other Equipment section.
XLR Microphone Connections (And Other Analog Connections)
XLR is the most popular connection for professional microphones.
XLR (a 3-pin (3 wire) connector that carries balanced sound is:
- Pin 1 is an electromagnetic shield and ground wire.
- Pin 2 is used to carry the audio signal in positive orientation.
- Pin 3 is used to carry the audio signal in negative orientation.
The XLR cable will be balanced if it carries the same audio signal but with different polarities on pins 2 & 3.
The mic preamp, which we’ll talk about later in the article, is a differential amplifier that adds the difference between pins 2 and 3, creating a signal twice the audio signal’s strength on the pins.
The differential amp cancels any noise on both pins, including EMI, RFI, and even +48VDC phantom power. This is not noise.
The XLR cable can carry phantom current (an equal +48VDC on pins 2 & 3) to microphones that need it. In the next section, we will discuss phantom powers.
You will also notice that the Mini-XLR and TRS connectors and the Tube PS connectors and Tuchel are balanced.
Insert the male plug into the female jack to physically connect with XLR.
Know more about XLR microphone: https://www.howtogeek.com/404747/what-is-an-xlr-microphone-and-why-do-i-want-one/
Wireless Microphone Connects
Wireless microphones can be connected wirelessly using a wireless transmitter or receiver tuned to the same radio frequency.
The microphone should be connected to the transmitter. The transmitter will embed the microphone’s audio signal in a radio signal and transmit it wirelessly to the receiver.
The receiver decodes the radio signals and extracts the audio signal from the microphone. The wireless receiver then decodes the radio signal and extracts the mic’s audio signal.
This is usually done at mic level. Once the receiver has decided, it should be connected to a mic preamp, just like a wired microphone.
These connectors are used to connect modern wireless microphones to transmitters. I’ve included examples to illustrate each type of connection.
- XLR: (example: Sennheiser SKP 100 G4-A).
- TA3 (mini XLR): Samson PXD as an example.
- TA4: Exemple: Shure GXD1.
- TRS: (example: Sennheiser EW 112P G4).
The transmitter wirelessly transmits the mic signal to the receiver.
A receiver as long as the frequencies match.
The signal is then sent to the receiver via:
- XLR: (example: Sennheiser EM 100 G4-A).
- TRS: (example: Sennheiser EK 100 G4).
The wireless receiver connects then to the mic preamp.
Other in-line devices This is usually done using an XLR
Cable or a 3.5mm (1/8″) TRS-XLR adapter cable.
Digital Microphone Connections (USB and Other)
Because of their simplicity and ability to improve computer audio, digital microphones (especially USB mics) have become more popular.
It is easy to connect a USB microphone by plugging in the appropriate USB cable into your computers.
You must have an adapter cable or an analog-to-digital converter to connect a microphone digitally.
Tube Power Supply Unit Connectors
We must plug in the correct power supply to a microphone that requires external power (such as tube mics).
PS connectors will typically have a ground pin, pins to carry balanced sound, and pins that carry the correct power. Different connectors may be available depending on the microphone.
The microphone audio will usually run from the microphone to the external power supply unit (PSU). The balanced audio can be sent to the mic preamp via the PSU output, which is usually an XLR connector.
The Other Connectors
There are many microphone connections available on the market. We’ve only covered the ones you will see most often.
Lavalier mics cause most confusion regarding microphone connectors with their wireless transmitters. We’ve discussed this earlier. The vast majority of professional mics use XLR, as mentioned.
Properly Power Active Microphones
Passive microphones can be connected to a preamp to receive a signal. To function properly, active microphones require power (electricity).
And this is how it works:
- Passive microphones don’t require power (moving coil dynamics and most ribbon dynamics).
- Power is required for active mics (electret and true and tube condensers and active ribbon dynamics). Powering active mics is necessary to make them work.
Active Components (What Does It Take To Power?)
What makes a microphone passive or active? It is the presence or absence of active components. These are the main active microphone components:
- Condenser caps that are externally polarized: To function, condenser caps must have a fixed charge across their backplate and diaphragm. This fixed charge is provided by external powering methods in non-electret microphones (true condensers)
- FET/JFET impedance converters: These transistor-based impedance converters use the extremely high-impedance signals of condenser capsules to create a low-impedance output that can travel through the rest of the mic circuitry.
- External power is required for these FETs or JFETs to generate an electrical current that allows the capsule signal to be modulated.
- Vacuum tubes: Vacuum tubes are impedance converters. They receive the high-impedance signal of the mic capsule and modify it to produce a stronger, lower-impedance output signal.
- Printed circuit boards: Sometimes active components, such as amplifiers, are found on printed circuit boards. These require external power.
- Analog-to-digital converters: Digital microphones’ ADCs need the power to convert analog mic signals into digital audio.
This power can be delivered in a variety of ways:
- Phantom power
- DC bias voltage
- External power supplies
- USB power
What is Phantom power? Phantom power is a way to get rid of your problems.
Balanced cables are used to power mics. Pins 2 and 3, which are relative to pin 1, receive a standard +48VDC voltage. It powers the microphones without affecting their sound.
The name Phantom power comes from its invisibility. It uses the same balanced cable as microphone audio. It even runs on the same wires that carry audio. It does this without being heard.
The following components are commonly used in active microphones to create phantom power:
- Capsules for a polarizing non-electret condenser.
- Provide the modulated current to FET/JFET impedance converters.
- Any amps that are within the mic can be powered.
It is important to note that phantom energy is insufficient to power vacuum tubes in tube mics or the ADCs in digital/USB microphones. These are the two main types of power that can be used.
You should also note that not all condenser mics require phantom powers and that some smaller electret microphones (like lavaliers) require a lower DC bias voltage.
Most microphone preamplifiers provide phantom power (in recording boards, mixers, and other audio interfaces). You can also get it from standalone phantom power supplies devices.
Neumann KM 84 (1966): First phantom-powered microphone on the marketplace
What is DC bias? DC bias is the method of powering microphones through a single conductor. The DC bias voltage ranges between 1.5 to 9V DC. It is used to power smaller electret microphones with impedance-converting FET and JFET.
The DC bias voltage is usually too low to power externally polarized condenser caps and certainly not strong enough for a vacuum tube.
DC bias is therefore used to power small electret condenser microphones or impedance converters (FETs/JFETs). Lavaliers are the most popular example of such mics.
The wireless transmitters of lavalier microphones often provide DC bias.
External Power Supply Units
What is an external power source? All active microphones used external power supplies before transistors, and phantom power was available in microphones. This was to power their vacuum tubes and polarize the capsules.
External PSs are still required to power the vacuum tubes of modern tube microphones, which consume a lot of power.
External power supplies are essential for tube microphones that consume a lot of power. The vacuum tubes cannot be heated properly by the phantom power mentioned above.
Tube mics have the following external PSU functions:
- Heats the vacuum tube for proper impedance conversion and pseudo-amplification.
- Polarizes the capsule
- This powers any other active component in the mic circuitry.
What is USB power? USB power is 5V DC at pin 4, relative to pin 1 (ground). This voltage is used for powering the analog-to-digital converters of USB microphones and the impedance convertors of USB mics using electret condenser caps.
As the name implies, USB power is used to power active components of USB microphones. These components include:
- Analog-to-digital converter.
- FET/JFET impedance convertors
- Internal amplifiers
It is important to note that USB power is not sufficient to polarize true condenser caps. Therefore, USB mics are usually either electret condensers (or dynamics).
The USB power can also be used to run the impedance converters with electret condensers. These impedance converters are not required for dynamic mics.
Some audio interfaces and standalone phantom power supplies use USB power to send phantom electricity to connected microphones. In these cases, the USB power is increased to supply +48V DC rather than the +5VDC carried through the USB cable.
Positioning A Microphone
After we have properly connected and powered the microphones, let’s talk about properly positioning them.
If we want our microphone to work at its best, it is essential to position the microphone correctly.
It is easy to connect, power, and provide gain. The microphone placement is an art that can make a big difference to the quality of the audio captured by it.
Understanding the mechanics and operation of microphone positioning is key to better understanding it. We’ll be discussing the following:
- The sound source.
- The acoustic environment.
- Positioning on-axis or off-axis
- Inverse-square law.
- The proximity effect.
We will also discuss stereo miking and miking techniques.
Know The Sound Source
It is crucial to know the source of the sound when choosing the microphone.
A kick drum sounds different from a guitar, and a vocal for death metal sounds different from a voice-over.
After you have chosen the correct microphone, it is time to place it correctly.
Know what sound source you want to capture and place the microphone correctly.
These are questions to ask about the sound source.
- Which frequencies are the sound source producing?
- How directionally is the sound source?
- How far does it take for the sound’s character to develop?
- What volume is the sound source?
- Is the sound source producing a lot of little air?
As an illustration, let’s look at an extremely common sound source. The human voice:
Vocal frequencies can vary between people. Speech intelligibility can be described as being within the 3 kHz to 5 kHz range. You should choose a microphone that can enhance this range.
Vocals project from the front of the singer’s mouth and are very directional. It is ideal to position a microphone in front of the vocalist’s eyes.
It doesn’t take much time to build the character of the human voice. Positioning the microphone close to the vocalist will increase the signal-to-noise ratio but not overly color the vocals.
Vocals are also not too loud so that condenser microphones can be placed close to the vocalist (with low max SP values).
Vocals naturally produce plosives. Positioning the microphone at a reasonable distance and slightly off-axis can reduce the volume of the mic signal.
If the intended sound source is a kick drum, full drum kit, acoustic guitar, electric guitar cabinet, piano, etc., we will position our microphone(s) differently.
Know The Acoustic Environment
It is important to understand the acoustic environment before placing a microphone.
Like professional studio booths, soundproof spaces are acoustically dead. The room is soundproof from the outside, and the sound is reflected off of the walls.
Therefore, we can position the microphone at an ideal distance from the sound source and angle without worrying about reflections, bleed or blur (unless other sound sources are in the same space).
We must consider other sounds sources when positioning our microphones on stages. This usually means micing close to the source.
Another problem with stages is their reinforcement, so feedback is important. This is covered in the Gain-before-feedback section.
Acoustic environments with reflective surfaces must be considered. We should position our microphones according to the desired results. A closer mic will produce a cleaner sound, while a distant mic will pick up more of the room’s character.
Try listening to different positions before you place your microphones when recording sound outdoors or in ambient settings.
Off-Axis Vs. On-Axis
A microphone, omnidirectional or directional, usually sounds best on-axis. This is the direction where the mic points or the front direction.
In general, our goal is to place the microphone in a parallel direction to the sound source.
If the sound source emits plosives (like the human vocal) or pushes air (like a kick drum), you may need to move the mic slightly off-axis to decrease the chance of the plosives/gusts overloading your microphone.
It is important to note that it reduces its effectiveness when a microphone is turned off-axis (in frequency response and sensitivity).
According to the inverse square law, the intensity of sound waves is proportional to their distance from the source. For every doubling in the distance from the source, the sound intensity drops by 50% or 6dB SPL.
This means that the closer the microphone is to the source, the louder the sound source will be. Close-miking produces a stronger signal from the intended sound source.
The Proximity Effect
The proximity effect refers to the increased bass response of a directional microphone when it is closer to the sound source.
The greatest influence of the proximity effect is in bidirectional microphones. However, it is also present in all microphone patterns other than omnidirectional.
A directional microphone placed too close to the sound source can cause a louder bass and muddy signals. This can be corrected by moving the microphone backward, taking into account the other factors.
Live sound reinforcement situations, where the microphone is amplified or projected by loudspeakers in the room, require us to be aware of microphone feedback.
These are some mic techniques that will allow you to get the best gain-before-feedback from your microphone:
- You should choose a directional microphone, but ideally a cardioid microphone.
- Point the microphone and loudspeakers in opposing directions.
- The null point(s) of the directional microphone should face the monitors.
- As far as possible, position the microphone away from the loudspeakers.
- The close-mic sound source(s).
For more information on gain-before-feedback, check out the following My New Microphone articles:
- What is Microphone Feedback and How to Eliminate it for Good
- 12 Methods To Prevent & Eliminate Microphone/Audio Feedback
Many miking techniques can be used in various situations, such as sound sources or acoustic environments.
To position your microphone at the most optimal location relative to the sound source, use the questions and factors above.
Use your ear to determine the microphone position.
Use omnidirectional microphones to plug in one ear and then listen to the other. You can move around until you find the sweet spot. Place the Omni mic there.
Use a cardioid microphone to plug one ear, and then cup the other using your hand. Turn your head so that the sound source is facing you. Locate the microphone in the best spot.
Stereo microphones (or coincident or near-coincident pairs, which we’ll get into in a moment) can be used to listen with both ears until the sweet spot is found. Then position the mic(s).
Stereo Miking Techniques
Stereo recording is the preferred method in music and video. Stereo miking provides a true stereo image from the beginning of the recording process.
Stereo miking requires at least two microphone capsules, either in two mics or in one stereo mic. These inherently mono microphone signals are panned during the mixing/recording stage to fit within a stereo picture.
Mic capsules can pick up sound sources from different locations in the acoustic environment. You can tell the difference in the spacing of the mic capsules and how they point.
There are four major categories of stereo microphone pair techniques:
- Pair of directional microphones placed as close as possible to each other in a coincidence. The directional capsules should be pointed at different degrees (often 90deg and 120deg). There are very few phasing issues with coincident pairs.
- Near-coincident pair: A stereo pair consisting of two directional microphones that point in opposite directions. Near-coincident pairs are the closest to natural human hearing sound.
- Spared pair: A stereo pair (omnidirectional or directional) of microphones. These mics are placed at a considerable distance from each other, allowing for a stereo image but avoiding potential phase issues.
- Mid-side coincident non-pair: This technique is also very common. It has a cardioid microphone pointing toward the sound source and a bidirectional microphone pointing at 90deg or 270deg. One copy of the bidirectional signal is hard-panned left, and one copy is hard-panned right, with the phase inverted.
Other Miking Techniques
Some microphones can be attached directly to the sound source. These include:
- Body mics/Lavalier: These mics attach to the clothing, hair, or skin of actors and other performers in theatre and film.
- Instrument microphones: These mics attach directly to the acoustic instruments they are intended to.
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Preamp Gain and Using Microphones with Other Equipment
Now we have our microphones plugged in, powering up, and properly placed. Let’s now discuss how to use the microphone’s audio output.
Microphones must be used with audio equipment.
Gain (or amplifying) mic preamplifiers are necessary to raise mic signals to such a high level. Preamps add gain to microphone signals to be used in conjunction with audio mixers or recorders.
Why can’t microphones output only line-level signals instead of mic-level signals? Mice naturally produce weak AC signals from their transducer parts. Although it is possible to place a powered amplifier inside each mic to increase the signal to line-level, it would be more expensive and change the models that process mic signals.
This is something I have thought about. It would be great to plug our mics directly into the line levels without using preamps, but it doesn’t make any sense marketing-wise or for gear compatibility. Internally amplifying new mics to produce line-level signals is not a good idea.
Use A Microphone Preamp
Preamps are what a microphone plugs into.
These devices usually have microphone preamps:
- Standalone devices.
- Audio interfaces (ADC + DAC).
- Audio mixers.
- Audio recorders
For professional mic connections, preamps often include female XLR connectors.
Connect the wired microphone or the receiver of the wireless mic to the mic preamp.
After connecting, adjust the gain until it reaches a comfortable level. It is best to place the microphone so that it faces the source of the sound. Clean audio signals can be captured by ensuring there is no clipping of the audio channel or preamp.
Mic Level to Line Level and Line Level To Speaker Level
Let’s look at the signal path and gain stages involved in bringing a microphone signal to speaker level. This is where the captured audio is projected into the air as sound.
Mic level: This is the signal level that the microphone outputs.
Microphone preamp: This device receives the mic level signal from the microphone and amplifies it, increasing its line level.
Line level: At this level, audio signal strength can be used in audio recorders and mixers. It is at a good level to convert to digital audio for digital mixers or digital audio workstations.
The power amp is an amp that boosts the line-level signal (output from mixers, recorders, and audio interfaces). The signal is boosted to speaker level before it reaches a loudspeaker.
Speaker level: This analog audio signal level can move the large diaphragms on loudspeakers so that audio can be turned back into sound that we can enjoy (or not).
You should also know that there are different types of mics for different needs. Choosing the right type of mic will also contribute to making the best use of the microphone.
Hooke Audio hopes our guide will help you to deep dive into using the mic effectively. If you have any better options, please leave them in the comments below; we’ll upgrade and finish the article when possible!