You would like to find out what gain is on a microphone. You don’t know how to find it. This is the right place for you.
To get a high input level, Gain controls are used most often. Gain controls an amplifier behind the scenes. After passing through the gain stage, your signal will ‘gain’ strength. Gain is the most important control in your signal path.
Continue reading this article to learn about what is gain on a microphone and how it affects signals, sounds.
- 1 What is Microphone Gain and How Does it Affect Mic Signals
- 2 How to Set Your Mic Gain?
- 3 How to Gauge Mic Gain?
- 4 So, How does the Microphone Gain affect Microphone Signals?
- 5 Why don’t the microphone output line level?
- 6 Gain Vs Volume
- 7 Pre/Post-Fader Levels On Mixers
- 8 Conclusion
What is Microphone Gain and How Does it Affect Mic Signals
Let’s begin our discussion by reviewing some basic information about audio signals.
An analog audio signal is an electronic signal. They are measured in decibels relative voltage (both are measured in dBu and dBV).
0 dBu = 0.775 volts
0 dBV = 1 volt
Decibels can be described as a logarithmic ratio. +6 dB effectively doubles the voltage, and -6 dB effectively halves it.
Although microphones are analog, they can output digital signals in certain cases. Gain is applied to analog signals. Digital gain is simply a multiplication or addition of the digitalized value, which results in a loss in resolution.
Mic Level and Line Level
Mic level signal is what microphones produce. Mic level is usually specified between a nominal 60 dBu or -40 dBu.
Professional audio equipment can only work with electric signals at line level (nominally +4 dBu). Mixing consoles and digital audio workstations are examples of professional equipment.
Both mic and line levels have nominal values of just average. These levels depend on many factors, including the sound source loudness, distance from the microphone to sound source, microphone sensitivity, gain applied to microphone signal, and other factors.
Mic level is considered to be 1,000 times stronger than line level. These mic-level signals need to be boosted to line-level to make them compatible with professional audio equipment. A gain boost of 44 dB-64 dB would suffice, according to the above nominal values.
Mic inputs expect mic level signals. A mic input should have a preamplifier built-in. This should be able to boost the mic signal to line level. The extreme risk of overloading a mic input is when a line output is connected to a mic.
Line inputs expect line-level signals. A mic output plugged into a line input will produce very low signal levels and a poor signal-to-noise ratio.
The Definition of Gain
Gain is an electronic term that refers to an amplifier’s ability to increase the amplitude of a signal from its input to the output. An amplifier applies gain on an input signal to make it stronger at its output.
By adding energy to the signal, you can gain. This energy is converted to an external power source (whether it’s an AC wall outlet, phantom power or batteries, or any other source).
In practical situations, there is two possible microphone gain (preamplification) stages that allow a mic signal through.
You can gain from an active preamplifier in the microphone (active microphones only). You can get a separate microphone preamplifier (standalone or audio interface, mixing boxes, etc.).
Microphone gain refers to the gain that is applied to mic-level microphone signals.
This can occur inside microphones that have active circuitry, as mentioned. If the preamps are separate, the microphone gain is applied directly to the mic input signal.
Gain From An Active Preamplifier Within The Microphone
Condenser microphones and active microphones include an active preamplifier in the microphone body. A microphone gain capsule produces an audio signal that is too low in voltage or too high in impedance for it to be useful.
An active amplifier is installed directly after the capsule. This is done to raise the voltage to acceptable levels and immediately reduce the signal impedance.
The signal can travel through a reasonable length of the cable without being affected by high impedance.
Gain from an active microphone’s built-in amplifier is usually a fixed value.
Attenuation pads are used on many active microphones to reduce the output volume of the capsule before it reaches the internal amplifier. These pads prevent overloading of the active circuitry/amplifier and subsequent signal distortion.
Active amplifiers increase the signal strength of the microphone. The gain they provide isn’t strong enough to amplify active microphone output signals at line level.
AKG C414XLII is a great example of an active condenser mic with an integrated FET. The mic outputs mic-level signals even with the amplifier though.
Gain From An Active Preamplifiers In USB/Digital Microphones
USB microphones and other microphones that produce digital audio have integrated analog-to-digit converters (ADCs).
A lot of them will also have a mic preamp before the ADC.
The preamplifier built into the microphone should have an adjustable gain that effectively brings the mic’s signal up to the line before converting it to a digital signal.
Blue Microphones’ popular USB microphone, the Blue Yeti (link to see the price at Blue Microphones), has a mic preamp and ADC. The microphone acts as an interface with its DAC and headphone amplifier.
Gain From A Separate Microphone Preamplifier
Professional microphones all output mic-level signals, so they require gain to bring them up to line level. Microphone preamplifiers provide this gain!
The mic input of a preamp is subject to microphone gain.
This distinction is important when working with multiple input channels. Don’t plug your microphone into a line input. Line inputs expect stronger signals than the mic level and won’t provide enough gain to boost the microphone signal.
Nearly all audio recording and mixing is done at the line level, digital or analog. It is crucial to get analog audio up to line level with gain. ADCs that convert analog line-level signals into digital signals is essential.
Professionals prefer standalone preamps, even though mixing consoles often have preamplifiers built-in. Make sure you are connecting the standalone preamplifier directly to the mixer.
A digital/analog converter can be used to connect standalone preamps to DAWs. DAWs can also use an audio interface to provide mic inputs. Audio interfaces have built-in preamps.
Mic preamps are circuits that amplify mic inputs to line-level. A microphone preamp is almost always the first circuit to which a microphone’s output signal is exposed.
A mic preamp prepares the microphone’s audio signal to be used in all other audio devices.
How to Set Your Mic Gain?
You now know what mic gain is and how it works. You can adjust the gain microphone by adjusting a few factors.
The volume of the sound source is one factor. You will need to increase the mic gain if you are recording silently, whether for recordings of ASMR video, or just a conversation.
You may need to lower the mic gain if you’re recording a band that includes a guitar amp or other loud instruments.
The distance from the microphone is another factor. You will need to increase your mic gain the further away you are from the microphone. Mic gain will be lower the closer you are to it.
Last but not least, consider the microphone’s sound sensitivity. Some mics pick up sound more than others. To balance the sound, you should lower your mic gain if your mic is sensitive. If your mic is having trouble picking up sound, your mic gain should be lower.
How to Gauge Mic Gain?
Your ears are the best way to determine mic gain. Your mic’s sensitivity should be below, and you are far away from it, but if the mic sounds like you are shouting, then your mic gain may be too high.
Your ear and the sound you want to create your podcast are key factors in determining your mic gain.
If you want to create a high-quality sound, microphone gain staging is essential. Microphone gain staging ensures that all devices produce the highest quality sound.
Two key elements in maintaining a clean sound are the noise floor and headroom. Headroom refers to the amount of signal that is available above the noise floor.
Gain Staging determines how loud you can make the sound. Noise floor refers to the sound coming from your audio devices or AD/DA conversion.
Your sound should be as loud as possible above the noise floor. Gain staging is crucial because it determines the quality and quantity of your sound. Your output will become choppy or distorted if it is not.
So, How does the Microphone Gain affect Microphone Signals?
Mic gain is the art of amplifying the microphone signal to line level. There are a few factors that will determine how much gain is needed:
The microphone’s sensitivity (signal output per level of sound pressure)
The distance to the microphone and its loudness.
For example, the first is that active mics (condenser mics) have built-in amplifiers, making them more sensitive to sound than passive mics (moving coil dynamics). A condenser microphone will need less preamp gain than dynamic mics to reach line-level signal strength, even if everything else is equal.
The second point could be illustrated by the fact that a microphone placed near a kick drum will require less gain than a mic placed farther away to reach line-level signal strength.
A microphone placed close to a kick drum would require less gain than a microphone placed in front of a person performing a voiceover.
When adjusting the gain of a mic input, it’s important not to overdrive or clip the signal (typically, this is shown by a red light on the mixer/preamp/interface/etc.).
The aim is to amplify the signal to a minimal line level, making it comparable in signal strength with other instruments, guitar amp, and microphones.
Why don’t the microphone output line level?
This question needs to be answered. Why aren’t microphone manufacturers able to build preamps in their microphones so that their microphones can output line-level signals?
Marketing and history are the simple answers.
It doesn’t make sense to alter the format when so much gear is made the same way.
Marketing perspective, it doesn’t make sense to combine preamps with microphones in one unit. This would be possible with the current technology.
Gain Vs Volume
Gain control is a function of plugging in a microphone to a preamp. Gain control is usually a gain knob. The gain control can be turned clockwise to increase the gain and counterclockwise to decrease the gain. The gain value is expressed in decibels.
When it’s time to use the audio signal, we will typically use a channel strip (on a mixing console or DAW) once we have the gain set correctly.
To adjust the volume, we will use volume controls (typically a fader). You can also see the book in dB values.
Difference between gain and volume:
Gain is used to adjusting the signal strength of each microphone and instrument so that gain and volume are all equal near the nominal line level.
Volume is used to balance each instrument and microphone in the mix.
Gain adjustments first. Volume adjustments are second!
Pre/Post-Fader Levels On Mixers
I thought I’d write some paragraphs about pre-and post-fade levels for mixing consoles concerning gain, volume, and mixers.
Volume faders are used to adjust the volume of mixer outputs. Sometimes, however, we may need to use auxiliary mixes.
An auxiliary mix can be defined as a mix that is not part of the central mix.
Mixing consoles have auxiliary send knobs that can send a channel strip signal for auxiliary mixes. These sends can either be set to pre-fader (or post-fader) mode.
- Pre-fader refers to the signal being sent only based on gain adjustments. The volume fader is not affected by the movement. The pre-fader signal level is not affected by moving the volume fader.
- The signal is sent post-fader based on volume and gain adjustments. The volume fader is removed from the movement. The post-fader signal level can be changed by moving the volume fader.
To explain pre/post-fade, I will use an example of requiring a signal, not in the central mix.
Let’s assume that a producer uses this microphone to speak to a sideline journalist. The producer must be heard by the sideline reporter but not through the main broadcasts.
We want to accomplish this by doing the following:
- Adjust the gain of your producer’s microphone to the nominal level.
- Adjust the volume fader to -dB
- Send the channel signal to an audible mix, then to the sideline reporter’s earpiece.
- Adjust the aux send to pre-fader.
This will send the signal prefader, which is based only on the gain adjustment and not post-fader, which would be based on volume adjustment (in this instance, there would be no signal due to -dB volume level).
The microphone preamplifier is a complete circuit with gain control. It is the first circuit that an audio signal meets after leaving the microphone. It is, therefore, the most crucial circuit element of the entire mixing console.
We hope this article answers your questions. Understanding mic gain can help you create high-quality sounds in the future. If you have any questions or feedback, please leave a comment below. If you find this guide useful, please share it with others. We are grateful for your time at hookeaudio.com.
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