How to Remove (Isolate) Vocals in Adobe Audition

Introduction

This article will look at the removal of vocals from a piece of music. Music is composed of different elements. An audio music file will have a vocal part and the instrumentation part. The existence of these two separately are often privy to a few people sometimes it can be limited to the producer who worked on the song. Such processes are useful to DJs who are looking to make remixes of songs.

This article looks specifically looks at an effect known as the Center Channel Extractor in Adobe Audition. This effect has numerous effects that can be used. You can amplify vocals, boost center channel bass, drop vocals by some dBs and not entirely remove them. It is a resourceful effect in making changes to the instrumental parts or the vocal parts of a song.

This article focuses on the process of isolation of vocals in which we end up with the acapella of the vocalist. The inverse of this process is attenuating or removal of vocals from an audio file. In this process, we end up with just the instrumentals.

Mixing and mastering songs come with different approaches. This has a huge effect on how successful your process will end up. This is further broken down in the conclusion part of this article. Before that here is the process of isolating vocals in Adobe Audition.

Isolating Vocals in Adobe Audition [Step by Step]

Launch Adobe Audition and import the audio file. After the file has been imported, head over to the effects rack.

Activate the first effect by clicking the arrow on the right and picking an effect. Clicking on the white arrow will open a dropdown list. From this list, hover your mouse over Stereo Imagery. This will open a new list and click on Center Channel Extractor from this list.

Alternatively, you can access this setting in the Effects option in the menu tab. The list that opens up has a Stereo Imagery option just like the process in the effects rack.

This will open the Central Channel Extractor dialogue box. In this box, there is a preset menu set to Default whenever you open this dialogue box. Click on that entry and a list of options will appear. From this list, click on Acapella.

Acapella settings are supposed to isolate the vocals removing the instrumental. But just picking this preset does not get an excellent sounding acapella.

At times it will only attenuate the level of the instrumental. This is a result of how the song was mixed.

Therefore, follow up with these settings highlighted in the image below.

First, check on the right side of the dialogue box. This is highlighted with 1. There are two scales. These settings do not need changing. The only thing that you are on the lookout for is where the center channel is set and where the side channels levels settings are also set. From my image, the center channel level is at zero and the side channel level is at -48dB. The -48dB is the amount of attenuation applied to the side channels.

Follow this up by ensuring that the Extract entry is set as Center. What this does is you get to attenuate and minimize the vocals which are at the center. This is highlighted as 2.

The next setting to look at is the Frequency Range is highlighted as 3. There are four predefined ranges but since we are going to be doing additional adjustments pick custom. A custom frequency range will start at 115 Hz and end at 17000 Hz. This means that any sounds below 115 Hz and those beyond 17000 Hz are removed. If you play the audio you will notice, you will notice that some parts of the instrumental will have been affected. Note that the described process is an attenuation process, to get perfect vocals you have to do additional adjustments.

You can refine the audio by dropping the end of the frequency range which in my image is 17000 Hz. Do this by hovering the mouse over this figure and the mouse pointer will turn into a double-sided arrow. You can then drag it to the left.

Keep playing back to ascertain that the effects are being applied nicely to the file and you are getting excellent results.

Once you are done with these settings head over to the Discrimination Tab. This tab is useful in further refining your audio by identifying the center channel.

The 5 sliders, largely focus on these two: Crossover Bleed and Phase Discrimination. These sliders take care of the bleed of the instrumentals that remain after picking the Acapella preset.

The Crossover Bleed slider when moved to the left will increase the audio bleed. This move will make the presence of the instrumentals more audible. Therefore for better results move it to the right and not further out to the left. Also, a move to the left ensures that your audio does not end up sounding more artificial.  When you adjust it to the furthest right it will remove the instrumentals. In this move, you are ideally separating the material that is at the center of the channel from the overall mix. Note that sometimes the end result might have an effect on how the vocals sound.

The Phase Discrimination slider deals with the bleeding of sounds as well as the separation of vocals from the mix. This slider has its figures set as a degree. The lower the degree of phase discrimination the more bleed you will get and also much of the vocals will not be isolated from the instrumentals. Also, do not use a high degree as it will have a negative effect on how the vocals will sound.

As audio quality varies from one to another, I will suggest always listening back as you adjust these sliders to make sure that you are getting perfect results.

Conclusion

Note that you will at times follow this process and not get an amazing acapella at the end. I will also point out that this process is available on other equipment, software, and websites. Their results are not amazing as well. As a matter of fact, none comes close to the process in Adobe Audition. Why? Adobe allows you to make further adjustments in an attempt at refining the final sound. The other options are sometimes done with a click of a button but are not that effective. Dj controllers have this feature with just a click of a button.

Now the end result is dependent on how the original track was mixed and recorded. Good results are from tracks whose vocals are contained in the middle.