Condenser microphones are one of the most popular types of microphones available. It is usually the preferred type of mic for recording vocals, acoustic guitar, drum overheads, and more. That’s because of how sensitive these microphones are.
However, for someone new to recording, condenser mics can be quite tricky to use. A common problem with condenser microphones is they can get very quiet, meaning the audio signal recorded will not be audible. But what causes condenser mics to be too low or quiet?
Here are eight reasons why condenser microphones are too low or quiet
- The microphone is not supplied with phantom power
- The input gain is low
- The mic is connected to a Line/Instrument Input
- The mic is connected to the Audio Interface/Mixer with the wrong audio cable
- You are far from the mic
- You are facing the wrong side of the mic
- Pad switch is turned on
- The audio cable is faulty
Some of these reasons are obvious, and some of them require some explanation. So let’s take a closer look at all of the reasons, one at a time, why condenser microphones are quiet or too low.
1. Microphone is not supplied with phantom power
As you may already know, there are three main types of microphones — Dynamic, Condenser, and Ribbon microphones. Ribbon microphones are the least known, and they are rarely used these days, but you will still find them in vintage recording studios.
This leaves us with two of the most popular microphones today — dynamic microphones and condenser microphones.
One of the major differences between dynamic microphones and condenser microphones is, dynamic mics don’t require a power supply to work. You can connect it to a microphone preamp and start using it right away.
On the other hand, condenser microphones require a power supply to work. This power supply is known as Phantom Power. The standard Phantom Power used for condenser mics is 48 Volts. When a condenser mic is not supplied with Phantom Power, it won’t work and will stay quiet.
Fortunately, most audio interfaces, preamps, and mixers can feed condenser microphones with Phantom Power. To supply phantom power to a condenser microphone, first connect the mic to the audio interface, preamp, or mixer, look for the button or switch labeled “48V” or “Phantom Power” on the audio interface, preamp, or mixer and turn it on. This will send 48V to the microphone through the XLR cable.
If your audio interface, mixer, or preamp doesn’t have phantom power, then you need a dedicated phantom power supply brick. This device will be connected between your condenser mic and audio interface or mixer. It will feed phantom power to the microphone, receive the audio signal from the mic, and then send it to the audio interface or mixer. Simple as that.
Neewer 48V Phantom Power Supply (on Amazon) is an excellent choice and always gets the job done. It’s a 1-channel phantom power supply brick, meaning you can connect only one condenser mic. It comes with an adapter and an XLR cable.
If you need an extra microphone input to connect another condenser mic, there is a 2-channel Phantom Power Supply (Amazon) also made by Neewer. Do check it out.
2. The Input Gain is Low
Microphones, regardless of the type, deliver a very low-level audio signal. The audio signal from microphones in itself is not audible. For this reason, audio signals from mics have to be amplified. This is the reason why preamps were made.
When processed through a preamp, weak microphone level signals increase the gain (voltage) of the signal so that it becomes loud enough for further processing.
Although there are standalone preamps, most audio interfaces and mixers have a preamp built into them. If you can see a gain knob on your mixer or interface, then there is a preamp built into it.
The gain refers to the amount or level to which the audio signal is boosted. When the gain on your preamp, audio interface, or mixer is too low, the condenser mic will be quiet. Essentially, the lower the gain, the quieter the condenser mic will be.
To boost the microphone’s signal, you have to increase the gain to an acceptable level where you get a clean and audible signal without distortion. This process is known as gain staging.
While the condenser microphone is in use, gradually increase the gain on your audio interface, preamp, or mixer until the VU meter on the device shows green without getting into the red. Green on the VU meter means the signal is loud enough to be further processed. When the VU meter shows red, it means the signal is distorting.
3. The Mic is connected to a Line/Instrument Level Input
Another reason why your condenser mic is quiet is that you didn’t connect it to the right input on your audio interface or mixer. Let me explain.
You will find three main types of inputs on an audio interface or mixer — Mic Level Input, Instrument Level Input, and Line Level Input.
Line level inputs accept only line-level signals. These are signals that have already been preamplified and are very strong signals. It can be signals coming from a preamp’s output, a digital keyboard or synthesizer, and more.
Instrument level inputs are designed to accept instrument-level signals. These are signals from an electric bass or guitar.
And Mic level inputs, as you may have already guessed, accept mic-level signals. These are very low signals that have to be preamplified.
This means, if you connect a condenser mic to a line level or instrument level input, the mic will be quiet. That’s because these inputs are designed to receive strong audio signals, not weak signals from a microphone.
For this reason, you need to always connect your microphone to a Mic Level Input on your audio interface or mixer. But how do you know the difference?
Mic level inputs on audio interfaces and mixers are usually XLR inputs, and Line/Instrument level inputs are usually ¼” TRS/TS inputs.
4. The Mic is connected to the Audio Interface/Mixer with the wrong audio cable
This ties in with the previous reason, and after explaining, you will understand why.
Combo jack inputs are increasingly becoming popular. Nowadays, combo inputs are the standard inputs on audio interfaces, especially the budget options.
But what are combo jack inputs?
These inputs accept both XLR mic level inputs and ¼” TRS/TS Line/Instrument level inputs. This means you can plug in a microphone, a guitar, a preamp, or a keyboard in this input.
However, something you should know is that the XLR inputs on a combo jack are routed through a microphone preamp, which boosts the microphone signal. On the other hand, the ¼” input inside a combo jack is not routed through a microphone preamp.
This means if you connect your microphone with an XLR to ¼” TS cable, the signal will be low or quiet. That’s because the mic signal will not be preamplified.
It’s just like you have connected the mic to a line/instrument level input, just as I talked about earlier.
You must connect your microphone to an audio interface or mixer with an XLR Male to Female Cable for it to work properly. This will ensure the microphone signal through the audio interface or mixer’s preamp.
This cheap XLR cable on Amazon is all you need. You don’t need to buy anything fancy or expensive (unless you have an extra to spend). They will get the job done.
5. You are far from the mic
This reason may seem obvious, but it may be the reason why your condenser mic is too quiet.
There is a component in a condenser microphone called the backplate. When this component gets hit by sound waves, it vibrates. This vibration is then converted into an electrical voltage, which is read off as an audio signal.
The farther you are from the microphone, the lower the sound wave’s impact on the backplate. Essentially, when you are not close to the mic, the sound waves from your voice do not vibrate the backplate as much. This means the audio signal generated is much weaker; hence the audio output will be too quiet or low.
Some people try to fix this issue by increasing the gain on the preamp. However, that will also boost the background noise in the audio signal, and in turn, make the final audio output practically useless.
So always ensure your condenser mic is as close to the sound source as possible. A good distance between the sound source and the condenser microphone should be between 6 to 12 inches. Anything beyond that is considered far.
6. You are facing the wrong side of the mic
Some microphones can capture microphones from all directions. This category of mics is called omnidirectional mics. Although there are a handful of condenser microphones that are omnidirectional, not every condenser mic is an omnidirectional mic.
There are many condenser microphones, which are directional microphones, meaning they can only pick up sounds from a particular area of the mic. This is a design choice by manufacturers to filter unwanted noise that may be captured by the mic.
If the sound source is being fed to the wrong side of a directional microphone, the audio signal will be much quieter or low.
The best way to check whether your condenser microphone is an omnidirectional or directional mic is to check the reader’s manual. Alternatively, you can try speaking in different areas of the mic to see where you get the loudest audio signal. This will let you know which area of the mic is designed to pick up sound.
7. Pad switch is turned on
Pad switch (or attenuation pad) is designed to reduce the loudness of audio from a microphone before it is preamplified. A typical pad switched, when turned on, will reduce a microphone’s audio signal by -10dB or -20dB.
There are some condenser mics with pad switches. You may also find pad switches on some audio interfaces and mixers.
If the pad switch is turned on, it will reduce the volume of the audio signal captured by the microphone, making the mic very quiet.
Verify if the pad switch is turned on on your condenser mic, mixer, or audio interface and turn it off.
8. The Audio Cable is Faulty
I think this is pretty much self-explanatory. Audio cables, just like any electrical cable, certainly don’t last forever.
After trying all these solutions and the issue is not solved, chances are that the audio cable is faulty. Purchase a new XLR cable or try out a different one to see if it works. That may be the solution.
I hope this guide helps you troubleshoot your quiet condenser microphone and get it to an acceptable dB level.