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How To Reduce Background Noise on a Microphone?

Wherever you are, if you are using a mic, there will be the risk of some background noise. And that applies if you are using mics for vocals, drums, guitars, an orchestra, or just some outside recording for a vlog or Youtube channel. And it can easily end up being a big problem.

Therefore, you need to find out how to reduce background noise on a microphone. Whatever you are using it for. 

Not Every Mic is The Same

Bit of an obvious statement because they aren’t. And not every environment presents the same problems either. You will certainly be confronted by a different set, from working in a studio to a live performance on a stage to a busy street with cars flying by.

Just as those elements have an effect, if you are working with a singer, so can they. All singers don’t sing the same way. They don’t even act the same way in the studio.

Some will naturally make more background noise than others through actions and movement. Even the way they sing. It’s how they are. You might be able to calm them down a bit. But you can’t change who they are.

Not Every Environment Is The Same

Furthermore, reducing background noise on a mic will have something to do with where you are using it. The environment will play its part in creating unwanted noise. Therefore, no single solution exists that fits all the different scenarios. 

If you are using your mic in a near acoustically perfect studio, the problems will be different than in your bedroom. There are some basic things that the ‘ordinary’ user can do to start with to begin to reduce ambient background microphone noise.

  • Move any noisy equipment away from the mic.
  • Close any windows to reduce external noise.
  • Make sure the mic is not too near a fan on the computer.
  • And if you are speaking, use a pop shield.

All very basic and obvious things, of course. And in some circumstances, it might not be possible to remove all the background noise. 

Before we look at ways of reducing unwanted sound, it might be appropriate to understand some things about audio noise as it relates to microphones.

What Is Microphone Noise?

What Is Microphone Noise

You can clarify mic noise as an unwanted sound. Something that is reducing the quality of your microphone’s performance. How long that sound lasts, and its level will determine its characteristics. 

Let’s look at some of the various noise issues you will encounter. Knowing these will help you learn how to reduce background noise on a microphone.

Continuous or Broadband Noise

What we call hiss, and other static noises fall into this category. It is a noise where acoustic energy gets distributed over a range of frequencies when it is collected by the mic.

Narrow Band Noise

Briefly described, it is an unwanted signal that is constant. The audio level remains steady and is often the result of badly shielded cables that are connecting up the mics or poor grounding.

Impulse Noise

These are pops or clicks or any other short, sharp sound. They are of short duration and are high-frequency sounds.

Random Background Noise

These will include various unwanted ambient sounds but are often easily dealt with singly. Not so easy if there are groups of them. They could include traffic noise, weather conditions (wind, rain, or storms), or background conversations. 

As I said, these are sometimes difficult to remove as a group of sounds. This is because they are produced from a variety of places with different volume levels and frequencies. The best way to deal with them is individually. That might be going back to my earlier comment about closing the windows or just asking someone to be quiet.

Electrical noise 

A hum or buzzing sound can often be a big problem, even if it is not particularly loud. You can perform some simple checks.

  • Ensure all recording equipment has the same power strip.
  • Keep main electric cables well away from mic cables, or if they have to cross, make sure they are at 90 degrees to each other.

A further consideration is if you are using a Fender Stratocaster or some other guitars with single-coil pickups. The lovers of the “single-coil sound” are in a constant war with the RFI or radio frequencies that surround us. And/or EMI, electromagnetic frequency interference. The 60/50Hz hum can be a real problem, although it doesn’t always seem to occur.

You Have Noise

Infuriating it is, and you have to get rid of it. Let’s take a look at some ways you can identify unwanted microphone sounds and then get rid of them. Let’s start with the mic and see how to reduce background noise on a microphone with a few easy options.

The Gain Setting For the Mic

The Gain Setting For the Mic

You are probably aware that some mics are more sensitive than others. When you choose to buy your mic, sensitivity is something you should consider very seriously. This is because when different mics are exposed to the same source levels, they can give you differing levels of audio output.

Whether a mic is right for a specific type of recording can be gauged. We look at the clipping point, the noise level, and the sensitivity. If you have a very sensitive mic, you might need less gain from the preamp. You may also find the headroom is lower before it starts to “clip” than a mic that has less sensitivity.

Clipping

Let’s just have a brief pause to ensure that all readers understand what I mean by “clipping.” When something is driven too hard, beyond its maximum capacity of output, it is called “clipping.” 

It is a type of distortion that occurs within the waveform. A rather harsh and distorted sound results if we push it too hard. Guitars might benefit; mics usually not. Sensitive mics will, therefore, clip before a less sensitive mic.

How Good is Your Mic?

This is another issue that will affect the result. Is the mic you are using rather poor quality? If so, then all the filters and all the processing you can muster isn’t going to make that much, if any, difference.

Dynamic or Condenser?

You can say that there is a difference between the sensitivity of a Dynamic and a Condenser mic. The Condenser mic will usually have a higher sensitivity than a Dynamic mic. This makes each of them more suitable for certain styles of use.

Even though one might be more sensitive than the other, the level of the signal can still be adjusted. Ideally, to the input level that is best using the right amount of gain from the preamp.

However, if you need to increase the gain stage, it may inevitably bring some signal noise. Therefore, you will have to be careful that any increase in gain does not adversely affect the audio signal. As a result, setting the gain on a microphone properly should keep most of the noise out.

Microphone Boost

Sometimes you may have a microphone boost control on your mixing console or possibly on your audio interface. If you are getting some noise, you can try turning that down or even off.

Microphone Windshield 

Let’s take a look at external sounds that you cannot control. If you are recording outside, then there are plenty of issues. Inclement weather, especially wind, is going to have a major effect. Although you can’t get rid of the wind, you can reduce its impact on the sound collection somewhat. 

You can buy coverings made of foam or fur or even a combination of both, known in the industry as ‘dead cats.’ These slip over the mic head and will help to block out wind noises. They also help to cut out plosives from the spoken word if you are doing a narration. Good products can reduce wind interference by up to 12dB. But any such windscreen will block an element of unwanted sound. 

Windscreens, or windjammers, as they are sometimes called, are available for all mics. An example is this Movo WS220 Professional Microphone Windscreen. Even if you are recording without adverse weather conditions, these will give you better, cleaner sound.

Pop Filters

When working with vocals, you need to try and remove any plosives or sibilance from the recording. It is, therefore, a good idea to use a Pop Filter.

  • Plosives are an excess of air pressure on the mic’s capsule that happens using certain letters like B or P.
  • Sibilance is the unpleasant sound that can be caused when emphasizing the letters S, T, or Z.

A pop filter will reduce or eliminate that problem. They are not usually used outdoors, more of a studio setup for a vocalist. It is just a filter that is placed between the singer and the mic. 

Easy to Use

It is easy to use, mounted on the mic stand, and has a small flexible boom arm holding the filter. This allows you to get the position of the filter in exactly the right area. It will also help to keep moisture off the mic head.

Built-In

Many mics these days have some form of pop filter built-in. However, it is a good idea to also use an external filter to increase the protection. One such mic is the Shure SM58 Handheld Dynamic Vocal Microphone. Likewise, Pop Filters are not expensive, as you can see from this NLL Microphone Pop Filter, and certainly worth the small investment.

Microphone Shock Mount

Microphone Shock Mount

Whilst the standard and sensitivity of mics has improved over the years, that sensitivity has brought with it its own set of problems. Even the slightest touch on a mic stand can send unwanted sound into the recording. 

Someone walking across a hard floor while in record mode can also cause noise. Using a handheld mic is usually a no-go in a studio. A good way of reducing sound caused by contact with the mic or any supporting structure is with a shock mount system.

The shock mount will reduce even handling noise if the mic is sensitive. Some mics come with their own shock mount system. Australian company Rode makes excellent mics, some coming with a shock mount. For a good example, check out this Rode Procaster Broadcast Quality Dynamic Microphone with Rode PSA 1 Mount.

Moving On

Having looked at minimizing as much ‘practical’ noise that can interfere with your sound, let’s move on. An area we should look at is removing microphone noise using sound processing. The application and use of these many processing options can be complex. I am, therefore, only giving the briefest mention to some.

Filters

The use of a filter will not change or add to the audio signal. They are used to highlight or reject some signals in certain frequency bands. In particular, those frequency bands that carry unwanted sounds. Let’s briefly consider four of the most used.

Bandpass Filter 

This is used to separate a signal operating in one frequency, or sometimes with a group of frequencies. It separates and filters it out from the signals on other frequencies.

Band Reject Filter

Effectively the opposite of Bandpass, it eliminates background noise by removing the frequency. This does have a limited effect on other frequencies.

Low-Pass Filter

This filter allows the lower frequencies, but it will reject any signals above the frequency level used for the cut-off. You would use a low pass filter to remove troublesome high frequencies from your signal.

High-Pass Filter

Operates the opposite way round. This filter will reject lower frequencies where there are sound problems. Other than filters, you can try the EQ if the filters don’t solve the problem.

Noise Gate

This is one to go to early in your efforts using processing options. It has a control that raises the cutoff threshold to remove noise. It works quite well with hiss and hum. But, be careful not to go too far. If you go to extremes, it will start to remove the frequencies you need and sound very artificial.

How To Reduce Background Noise on a Microphone – Final Thoughts

When it comes to unwanted sounds and getting rid of them, you will learn as you go on. You will recognize things and know exactly how to fix them. This is a learning curve for most people. So, take your time and learn through experience. The answer is in there somewhere.

Until next time, make yourself heard.

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