How to clean up an old audio recording. How to remove noise from audio? Deadlines for the task

It happens when you record sound outside of the studio, extraneous noise appears on the recording, which cuts the ear. Noise is a natural phenomenon. It is present everywhere and in everything - tap water gurgles in the kitchen, cars make noise in the street. It accompanies noise and any audio recording, whether it is a recording on an answering machine or a musical composition on a disk. But you can remove these noises using any audio editor. We'll show you how to do it with Audacity.

Audacity is an audio editor that has a pretty powerful noise removal tool. The program allows you to record sound from a microphone, line-in or other sources, as well as immediately edit the recording: trim, add information, remove noise, add effects and much more.

Let's take a look at the noise removal tool in Audacity.

Let's say you decide to make some kind of voice recording and want to remove unnecessary noise from it. To do this, first select an area that contains only noise, without your voice.

Now go to the "Effects" menu, select "Noise Reduction" ("Effects" -> "Noise Reduction")

We need to create a noise model. This is done so that the editor knows which sounds should be removed and which should not. Click on the "Create Noise Model" button

Now select the entire audio recording and again go to Effects -> Noise Reduction. Here you can adjust the noise reduction: move the sliders and listen to the recording until you are satisfied with the result. Click OK.

No "Noise Removal" button

Often, users have problems due to the fact that they cannot find the noise removal button in the editor. There is no such button in Audacity. To go to the window for working with noise, you need to find the "Noise Reduction" item in the Effects (or "Noise Reduction" in the English version).

With Audacity, you can not only slice and remove noise, but much more. It's a simple editor with tons of features that an experienced user can use to turn a recording made at home into high-quality studio sound.

Well, if you talk about everything and everything, then you need to talk a lot, so I’ll only talk about some of the most interesting functions for cleaning the recording from noise.

Let's assume that we already have an open sound file from which we need to remove the hiss of the tape. To do this, we select a fragment of the recording in which only one hiss of the tape sounds, without a useful signal. This can be a pause between songs, or pauses at the beginning and end of a recording. Therefore, one should not rush to remove pauses, they will help us a lot when cleaning the recording from noise. For a more accurate and accurate selection, stretch the wave image horizontally so that you can see the selected fragment in full screen and do everything neatly, without capturing anything superfluous in the selection. Unfortunately, I have not yet figured out how to do this using JAWS, if someone explains, I would be very grateful! To change the wave scale horizontally, you can use the mouse wheel or special zoom buttons in the Adobe Audition window.

Now open the menu "Effects" (Effects), select the item "Noise reduction" and in the submenu that appears again the item "Noise reduction". The noise removal window will open. In new versions of Adobe Audition, this option is opened through some other menus, but in version 1.0, which I use, the noise removal function opens this way.

A few words about the settings, the values of which I would advise you to change and set them to other values that differ from the default settings.

The first is the "FFT" combo box. If the value in this list is very small, the useful signal will also suffer significantly when noise is removed. If the value is very large, the write processing will take a long time, the useful signal will not be affected, but the cleaning efficiency will be lower. I recommend setting FFT to 6000, because as a result of my experiments with sound cleaning, I found out that this is the best option for cleaning up the most common noises, such as tape hiss or noise from a not very high-quality sound card.

Secondly, "Accuracy", by default it is 7, for stereo recording it is better to set the value to 14 or 15, this is already quite a lot, it makes no sense to set more, in my opinion, because apart from increasing the processing time, this does not give anything . And thirdly, Spectrum Decay. This setting defaults to what I think is 56, I suggest setting it to 0 as the higher the value, the less effective the noise removal. An exception can be made in cases where the hiss of the tape is too strong compared to the useful signal. Then in the attenuation of the spectrum, you can try to increase the value to get rid of some "metallic" chime that remains after removing such a strong noise.

So, the noise that should be removed from the recording is selected, the noise removal window is open. Press the "Get from selection" button in this window and wait for a while. A bar appears on the screen showing the percentage of the process completed. When the scale reached one hundred percent and disappeared, everything is ready, we provided the program with a noise sample that needs to be removed from the entire recording.

There are two buttons in the noise removal window, "Ok" and "Close", Click "Close", since clicking the "Ok" button will start the cleaning process, but we don't need it yet. Also, don't close the noise cleanup window by pressing Alt+F4, clicking on the cross or clicking the "Cancel" button, as this will undo everything that we did in the noise cleanup window. After the window is closed, we need to select the fragment of the record to which the noise cleaning will be applied.

Here I want to draw attention to the fact that all Adobe audition functions apply only to the selected fragment of the recording. If the fragment is not selected, any triggered operation will be applied only to that part of the soundtrack that is currently on the screen. Therefore, if we want to apply the noise cleaning function to the entire recording, after closing the noise cleaning window, press the ctrl + a combination to select the entire audio track. After that, using the method already described above, open the noise removal window, press the "test" button and listen, our recording will sound the way it will sound after processing. if everything suits us, press the "Ok" button and wait for the end of the processing process.

Another important point: it is possible that after the first cleaning, the noise will not be completely removed. The noise removal function has one property: the farther we go along the record from the place where we took the noise sample, the more this same noise that we removed begins to appear. I do not know what it is connected with. Either the noise changes slightly over time and no longer matches the received sample, or the noise cleaning function, the further, the more mismatch with noise occurs. Therefore, it is possible that in order to completely get rid of noise, after processing, you will have to select a sample of one noise again, in the place where it remained, and repeat the entire operation. The noise removal function works very well on homogeneous or cycling noise. To remove, for example, the crackle of a record, I would strongly advise you to first use the function of removing crackles and clicks (Clip pop eliminator), and only then, remove what remains using the noise removal function.

Adobe audition has a hiss removal function specifically for removing hiss, but it seems to be based on the use of some kind of frequency filters, when using it, the hiss is not particularly removed, and the quality of the main signal suffers. Therefore, if there is a place on the phonogram from which you can get a sample of one noise without a useful signal, then to remove hiss it is better to use the noise removal function by sample, rather than the hiss removal function. If you made a recording, for example, from a cassette or a phonograph record, I strongly advise you to cut one song from it and process each composition separately, and not the entire large recording at once. This is how you get the best results.

After the noise removal is completed, you can remove all unnecessary pauses at the beginning and end of the recording, apply some more functions if necessary, for example, sometimes it can be very useful to correct the frequency characteristics of the recording using an equalizer. And as the final stage of record processing, you can perform normalization.

Normalization

A little about what types of normalization are and what it is in general.

Normalization is bringing the volume level of the recording to some specific value, for example, to the maximum allowable volume level. After normalization, firstly, your recording will not sound quiet, if you wish, you can turn it on on any computer or player and use all the possibilities of its acoustics in terms of volume. And secondly, if you recorded several tracks and normalized them all to the same volume level, they will all sound the same and it will not turn out that one song sounds louder and the other quieter.

The first normalization option is peak normalization. The principle of its operation is this. The program analyzes the entire recording and finds in it those places where the volume reaches the maximum value, and after that, increases the volume of the entire recording so that these places reach the maximum allowable value.

Peak normalization is very well suited for classical music. But, she also has a downside. For example, in our musical phonogram there is, say, a drum, which, at some point, was beaten so that it sounded much louder than all the other instruments. Naturally, this sound is the loudest in the recording, peak normalization will focus on it and increase the volume of the recording so that this fucked-up drum reaches the maximum allowable volume value. But all the other instruments sound much quieter, as a result, the recording turned out to be quiet, only this very drum thumped loudly enough once. Yes, such normalization will not introduce any distortions into the sound, but if such a drummer comes across, it will not work to get the desired recording volume, but, for example, as I already wrote, this is a good option for classical music, since it will not make any other changes to the sound except by changing its volume.

In Adobe audition, you can use peak normalization in the following way: select the entire record by pressing ctrl + a, open the effects menu, select the "Amplitude" item in it, and "Amplify" in the submenu of this item. In the window that appears, on the "Constant amplification" tab, there are one or two volume controls, depending on whether we have a mono or stereo recording. You can move the controls manually, or you can click the "Calculate" button. Then the program will analyze the recording and set the controls to the value itself, in this case, necessary for the peak normalization of the recording.

After that, it remains only to press the "ok" button. You should also pay attention to the checkbox "Block left right". If the checkbox is checked, when calculating the peak normalization level, the program will focus on the loudest sound in one of the two channels, but will set the volume controls so that it does not change the volume ratio of the left and right channels. If the checkbox is unchecked, each channel will be normalized individually.

The second type of normalization is Um, I'm sorry, tense with terms, I forgot what it's called. But, its essence is that it does not just change the volume, but, apparently, in some cunning way processes the numerical values of our digital recording. The essence is something like this. They play, for example, simultaneously, the balalaika and the violin, they play at the same time, but the balalaika player balalaika so loudly that it completely drowns out the violin. After our second type of normalization with a forgotten name, :-) both the balalaika and our muffled violin become more or less audible. Now, our "drummer" can drum as loudly as he likes, he will no longer be able to drown out everyone else.

Personally, this method seems to me suitable for most cases and is very good for processing digitized live recordings. For example, if someone shouted loudly into the microphone, this shout, after normalization, will no longer seem too harsh and much louder than all the others. At the same time, such normalization does not mean at all that all noises will be blown out, especially in pauses. Not at all, this type of normalization does not change the volume level in different places of the recording, the recording amplification is the same throughout the entire recording.

Although, if there is noise on the recording that was previously drowned out by the useful signal and was not heard, it may take a more prominent place against the background of the volume of all instruments.

In Adobe audition, such normalization can be used by selecting the "Amplitude" item in the "Effects" menu, and the "Normalize" item in the submenu of this item.

The third type of normalization is the so-called strict limiting. It operates on the principle of AGC (or ARUZ), radio amateurs will understand me. This type of normalization changes the amplification level of the recording depending on the volume of the original version at the current moment. For example, if someone barks loudly into the microphone, the program will lower the volume at that moment, and when someone speaks softly, the program will increase the volume so that they can be heard better. To use this for music, of course, is a complete desecration of the phonogram, but in cases where several people are talking, one is sitting far from the microphone, the other is closer, and the third is very close, this method of normalization can help, but only on condition that there is no noise on the recording and the interlocutors are talking in silence, otherwise it will also be an outrage, since in the pauses between words the noise will mercilessly come to the fore (you can set the input signal level, starting from which this type of amplitude correction will operate, and thus to exclude noise from the process, but then the quiet voice of one of the interlocutors may also "fall out").

In Adobe Audition, strict amplitude limiting can be applied by opening the "Effects" menu, selecting "Amplitude" in it, and selecting "Hard limiting" in its submenu. The settings of this function are made by analogy with a hardware device. "Input signal level", "Seek rate" ("sleep rate") and "fade rate" ("sleep rate").

After everything is denoised, edited, processed with other effects and normalized, you can save the recording. The only thing is that denoising, especially the click removal function, must be applied before normalization is performed.

Well, that seems to be all the most basic about cleaning up the sound and bringing it to normal sound in Adobe Audition.

Sometimes your footage can have a lot of noise, simply because there were extraneous sounds in the background during recording. However, do not rush to click on the "Delete" button. In most cases, this can be easily fixed.

In this tutorial, we'll show you how to reduce background noise in a recording using the free VSDC Editor. If you have not installed the editor on your computer yet, then you can download it from the official website.

VSDC offers 2 powerful noise removal filters: Median and Gate.

Gate is one of the most popular techniques in the post-processing of an audio stream. This filter is especially useful when you're working directly with recordings trying to remove unwanted sounds between passages because it's very effective at identifying persistent noise sources such as hum, hiss and buzz - and reducing them to a minimum.

Technically, when you gate, you control when and to what extent the sound passes through the channel. In other words, you are creating a shutter to filter the sounds in the video.

There are three reasons for using a gate:

Reducing unwanted external noise
Natural noise reduction
Using the gate as a special effect

Here's how it works. The threshold is controlled by setting several parameters:

Now that we've covered the process of applying a gate, let's move on to how the Median filter works.

The median filter helps to eliminate impulsive noise in your recordings. In a nutshell, it can be ideal for removing unwanted frequent sounds such as clicks and pops.

We hope this guide was helpful. Even though it may sound (or look) very difficult, once you get started, you'll find that noise reduction is quick and easy. Now try it yourself!

One of the most common problems that arise when working with audio files is the elimination of various noise and interference. In most cases, they appear in the process of recording from a microphone, but are caught, as a rule, already as you listen. This may be due to poorly tuned hardware. To clean the track from unwanted sound defects, you need to use high-quality. The AudioMASTER audio editor from AMS Software is the best solution in this situation.

So, today we will talk about how to remove noise from an audio recording using the AudioMASTER program. The algorithm of actions is simple: follow the instructions below and you can easily learn how to process audio.

STEP 1. INSTALLING THE PROGRAM

Before you start, you need AudioMASTER on your computer, and then install it. The size of the distribution kit is 50 MB. Remember that the download speed will depend on the speed of your internet connection. After the download is complete, run Setup Wizard double click. Be sure to transfer the program icon to the desktop so that it is easier to access.

STEP 2. ADD AUDIO RECORDING

Click the button "Open file" in the main editor window. This will allow you to load the required audio track to edit it. AudioMASTER supports the most popular audio formats - MP3, WAV, WMA, OGG, FLAC. In addition to downloading from a PC, you can save music from a CD if the disc is in the drive. After a while, the music file will open.

STEP 3: REMOVE NOISE

Now let's start looking at how to quickly remove noise from an audio recording. AudioMASTER offers you several options:

Equalizer setting. An equalizer is used to improve the sound quality of a track by adjusting its audio frequencies. In the action bar, click "Equalizer" and select the Noise Reduction preset in the column on the left. Using the vertical sliders, lower the level of a certain frequency until the noise disappears. You can control the process using the button "Listen". To apply the settings, click "Apply".

frequency filter. The frequency filter will help to highlight or remove the sound of a certain frequency. If you want to use this feature, go to the tab "Frequency filter" in the action bar. A list of presets available for editing will appear. Specify the numerical value of the selected frequency in the settings. The result can be previewed and then applied by clicking on the appropriate buttons.

STEP 4. SAVE THE FILE

Summing up the work, we will analyze two possible ways to save the processed file. The first way is standard - you can simply save the song in any of the proposed audio formats. To do this, click File > Save As in the main menu. From the list of available extensions, select the one you need. After that click "Save". The second option is suitable for those who want. Click in the main menu File > Save As Ringtone. In the dialog that appears Ringtone Wizard set the trim time and press "Save".

Compatibility

The program supports:
Windows 7, XP, Vista, 8, 8.1, 10

Not so long ago I needed to remove the noise from the sound. Previously, I did not do this, so I got on the Internet to dig out a way how this can be done with the least loss. After 10 minutes of searching, it turned out that all paths lead to Adobe Audition.

After half an hour of experimenting, I figured out the best way to remove the noise. Now I present to you a fairly detailed instruction on how to do this. I will try to collect all the information found together, summarize and write in an accessible language. I’ll make a reservation right away that there will be only instructions, and not a description of a bunch of filters for this monster (Audition). Instructions like “There is a problem - here is the solution for you.” And Audition is essentially Photoshop in the world of audio.

Let's say you recorded sound on a microphone, camera, phone. Often, these devices do not differ in special quality (in terms of sound recording). And there will always be noise - some kind of constant component. And if there is also a generator of additional noise (for example, the hum of coolers in a computer) ... Our task is to separate it from speech or music.

There are two options here:

The audio contains a recording of the atmosphere of a room or street without a useful signal. Those. in the presence of a recording of noise without impurities. For example, you are going to record your friend's guitar playing on a computer microphone. The apartment is quite quiet, there are no neighbors, no one makes noise on the street either (hmm, a rather idealized situation, isn’t it), but a disgusting computer, which is a hundred years old at lunchtime, and besides, it has not been cleaned of dust since the day it was born, treacherously rattles with coolers throughout Ivanovo. Well, there are two options: initially record 10-20 seconds before a friend starts playing and the same amount after the end. In this case, you will have a pronounced noise, which can later be separated. By the way, professional journalists do this whenever possible. And the second option is to clean the computer. And the second is clearly preferable.
There is no separate recording of noise in the audio. Those. your friend started playing immediately after the recording started, and after the end you instantly cut the microphone. Here is the worst option. The fact is that noise is a collection of certain frequencies. If there is pure noise, then it is safe to say that these frequencies are noise, garbage and can be removed from the entire track. If some useful signal goes along with the noise, then the selected frequencies will no longer be exclusively garbage. And, when you delete them on the whole track, some part of the useful signal will be lost. Or rather, the music and voice will acquire a metallic hue. Therefore, it is better to rewrite such a record. You can also try to find a section where the useful signal will be at a minimum, put less aggressive settings when cleaning noise and put up with a metallic echo. Or you can just write the noise sample to a separate file, unless of course you are 1000 km away from this place

There is a small original file of 5 seconds in size with a pronounced background noise. The recording was made on the voice recorder of a smartphone. And this noise is generated by the phone and at a low volume of the signal source is clearly audible.

Where to download the program, I will not tell you. I think you can guess without me. Let me remind you that you can download a trial version from the official Adobe website. You can use it for 30 days without restrictions.