In this article, I will answer all of your questions regarding microphone sensitivity. If you have any more questions, please leave them in the comments section below!
- What is Microphone Sensitivity?
- How Is Microphone Sensitivity Measured?
- How Does A Microphone's SPL Rating Relate To Other Sound Ratings?
- The Relationship Between Gain And Sensitivity
- Who Is More Sensitive; Europe, Or America?
- How Do I Check Microphone Sensitivity?
- What Is a Good Microphone Sensitivity?
- But, Does Microphone Sensitivity REALLY Matter?
- Can You Increase/reduce Microphone Sensitivity?
- Popular Microphones And Their Microphone Sensitivity & Max SPL Ratings
What is Microphone Sensitivity?
If you have used multiple microphones, you will come to realize some require more gain than others. This is due to the sensitivity of that model.
Microphone sensitivity is a measure of how well a microphone picks up sound from its source. It's measured in decibels (dB), and it can be found on microphones' specifications sheets, or on the manufacturer's website.
It is often considered to be one of the most important specs when choosing a microphone for your need, but it's also one of the least understood ones. But don't worry! We're here to clear things up!
The amount of amplification or attenuation a microphone provides is typically measured in terms of sound pressure level (SPL). 0 dB SPL is the threshold of human hearing. Most microphones provide amplification of somewhere between 60 and 100 dB.
How Is Microphone Sensitivity Measured?
Microphone sensitivity is measured in terms of sound pressure levels (SPL). The higher the SPL number, the more sensitive the microphone. For example, a microphone with an SPL rating of 120 dB is more sensitive than one rated at 100 dB.
Microphones are usually grouped into three categories according to their SPL ratings: low-sensitivity microphones (rated below 80dB), medium-sensitivity microphones (80dB to 94dB), and high-sensitivity microphones (above 94dB).
Low-sensitivity microphones are typically used for recording speech or instruments in a quiet environment, while high-sensitivity microphones are used for recording sound in louder environments, such as on stage or in a studio.
How Does A Microphone's SPL Rating Relate To Other Sound Ratings?
Here's where things get interesting. Most of the standard units of measure that people are familiar with—decibels (dB), Hertz (Hz), and watts, for instance—relate to each other according to some simple mathematical relationships.
Knowing this makes it easier to understand how different microphones can be characterized in terms of their sensitivities.
A microphone with an SPL rating of 80 dB, for example, is one-millionth as sensitive as a microphone rated at 94 dB. Microphones are typically measured at distances of one meter or more from the sound they are recording. The further away they are from the sound, the lower the SPL rating will be.
The Relationship Between Gain And Sensitivity
A microphone will require more gain to produce an output signal if it is less sensitive. A microphone with a low sensitivity rating will require much more amplification to produce the same volume as a high-sensitivity microphone in front of the same sound source, because it's picking up less sound relative to the high-sensitivity mic.
Also, if two microphones are both plugged into preamps that have identical gain, a less sensitive microphone will require more amplification to achieve the same output level as a more sensitive mic.
Another important relationship is between distance and SPL. As a microphone gets farther away from its sound source, its SPL rating decreases accordingly. This means it needs even more amplification to achieve the same output volume.
Who Is More Sensitive; Europe, Or America?
Different countries measure sound sensitivity differently. For example, in America, it is measured in relation to a microphone that would produce 1 volt if exposed to a sound pressure of 1 pascal. Whereas in Europe, it is measured in millivolts per pascal, so 1 mV/Pa.
If you want to understand the sensitivity on an American scale, take the number and subtract it by 20 (remember that negative numbers mean greater sensitivity). So, for example: -40dB is much more sensitive than -50dB.
There are benefits to this system, for example, you can easily estimate how much gain is required for an average medium-level sound source.
How Do I Check Microphone Sensitivity?
If you have purchased a microphone, the sensitivity has already been set during manufacturing, you will not need to test it yourself as the sensitivity information will be present on the box, on the site or manual, or on the sales page of the microphone.
If you are unsure about the brand or model of a particular microphone and want to test it yourself. This can be done using an SPL meter and while this method is very accurate, not everyone has access to one of these or even knows how to use it correctly.
You can purchase sound pressure level (SPL) testing equipment like this SPL Meter below, which allows you to test microphone sensitivity and other details. Again, these are the most accurate method of testing but not everybody can afford these so the guide on the website will be the next best bet.
What Is a Good Microphone Sensitivity?
This question is difficult to answer because it depends on the application. A lower sensitivity rating means that more gain needs to boost your mic signal from below-normal levels into something which can be handled by an audio processor or DAW (Digital Audio Workstation) without too much distortion.
But also keep in mind how many dBs of headroom these devices have when capturing signals at different volumes before compression happens – so that you can still achieve a good dynamic range and at the same time you don't overdrive your input signal.
An application where lower sensitivity is better would be, for example, to record someone who speaks very soft and close to the microphone and does not move around much, or maybe an instrumentalist or singer in a loud acoustic environment.
Mics with high open-circuit voltages will usually require less additional voltage via phantom power supplies before reaching line level; this makes them ideal choices during interview situations where low output sound levels are desirable.
But, Does Microphone Sensitivity REALLY Matter?
Microphone sensitivity is not a terribly important specification to consider when choosing a mic. This is because any value above about 8 mV/Pa is more than enough for good noise performance with most preamps.
Some people think that high sensitivity can compensate for a mic with a mediocre self-noise figure. But this is not true, because, for noise measurements, the gain must be adjusted according to the mic's sensitivity anyway.
Can You Increase/reduce Microphone Sensitivity?
You cannot increase or reduce microphone sensitivity on a computer. The microphone is a sensitive device that picks up sound and sends it to your computer. You can, however, change the settings on your computer to make the microphone more or less sensitive.
On a Windows PC, go to Control Panel > Sound > Recording tab. Under “Levels” you will see the slider for Microphone (and other devices). Slide the bar to the right to make the microphone more sensitive and to the left to make it less sensitive.
On a Mac, open System Preferences and click on Sound. Click on the Input tab and then look for the Microphone input level under “Levels.” Slide the bar to the right to make the microphone more sensitive and to the left to make it less sensitive.
With regards to the mic itself, adjusting the gain will be the way to control its sensitiveness.
Popular Microphones And Their Microphone Sensitivity & Max SPL Ratings
Here are some of the most popular microphones on the market and their sensitivity and Max SPL. But as mentioned above, sensitivity probably is not the most important factor when choosing a microphone.