Audio Editing

Published Date
01 - Dec - 2004
| Last Updated
01 - Dec - 2004
 
Audio Editing

We all love music! It’s merely tastes and the genres we listen to that distinguish us. Unfortunately, not all of us are talented enough to make music, but with the right software, anyone can edit and tweak their favourite songs. Whether it’s mixing favourite tracks, or creating non-stop compilations, or even editing one’s own little creations to make it sound more professional, there is software out there that will ease the task.

The first mistake most of us make is pessimism—as soon as we open an editing software, we see Sine waves and audio professional jargon, and are easily intimidated. However, Digit is here to show you that things are not as hard as they seem.

The two most popular Audio Editing software in use today are Sony Sound Forge (previously known as Sonic Foundry’s Sound Forge) and Adobe Audition. Here we will give you tips and tricks on how to put both these software to good use.

Normalising A Track

When you open a track to edit, the first thing you should check for is ‘clipping’. Some badly recorded tracks may have certain overtly loud sections, which will distort at loud volumes. These sections are said to ‘clip’. These are easy to spot when viewing the track as a wave form.

The wave form view has a left and right channel wave for stereo tracks, and each track has an X axis, also called the infinity line. The Y axis limit, both towards the negative and positive, is 0 db (zero decibels) for both left and right channels. If a wave peak crosses this 0 db barrier, it is said to clip. In order to prevent it from clipping, you can normalise a track.

Normalising an audio clip converts the track in such a way that the highest peak (the loudest sound in the audio file) hits exactly 0 db. Now you will have distortion free audio.

Normalising can also be used on a track that is too soft—where the wave form never comes close to touching the 0 db line.

It can also be used to normalise just a section of an audio track.

Sound Forge

To normalise a track or a selection in Sound Forge, select the part of the track you want to normalise, or select the entire track by using [Ctrl] [A]. Now go to “Process > Normalize…”. Make sure that the Peak level radio button is checked and the slider is set to 0.00 db. Click OK to normalise.

Audition

Select a part of a track, or the whole track. Go to “Effects > Amplitude > Normalize…”, make sure that ‘Decibels Format’ is checked and that ‘Normalize to’ is set to 0. Click OK to normalise.

Selecting Part Of A Track

When selecting a part of a track, you need to know where your selection should begin. For example, if you are looking to select an event, such as when the vocalist starts singing, or when the drum beat kicks in, you need to find the exact spot. If you are even a little off, you will end up with a selection that does not follow the songs’ tempo (beats per minute or bpm). If you select, say, six beats of an eight-beat song, you will not be able to loop your selection, or mix it with the same song—the beats will sound off.

In order to properly select an event, you need to listen to the song tempo and the beat count, while playing it and watching the wave form with a viewable zoom. This will give you an approximation of where your event lies.

Once you get a fix on the general area you want to select, zoom in and find a spot where the wave forms of both the left and right channels meet the infinity line.

You can make out the difference between events just by looking closely at the wave form. Just before an event, you should see the wave subsiding, and just as the event begins the wave will rise.

The point in the middle, where the wave meets the infinity line is the exact beginning of the event. You can always loop and listen to your selection later to make sure you got the exact beat count and the entire event.

Sound Forge

You can place markers while listening to the song by pressing [M]. Once you have marked your selection roughly, you can zoom in and look for the exact beginning and end of your event.

Press [Shift] [Z] to get the marker to the nearest point where the wave meets the infinity line.

Now place a marker at the end of the event and double-click between the two markers to select the event. Click on the loop button, located at the top left of the screen, under the edit menu option, and press play.

Listen to your event a few times to make sure that you have got the entire event as per the beat count of the song. Now you can cut or copy, your selection and paste or mix it into the same file, or a different audio file.

Audition

Audition uses Cue markers. Press [F8] to insert a cue marker when playing a song. Later you can zoom in to correct these markers. Use the standard keyboard shortcuts to cut, copy and paste your selections.

Merging Tracks

You can merge two tracks, or create a loop by merging a selection over and over. In both software, this is done by copying a selection or track normally. Now find the end of the track you wish to merge with, and then paste the selection or track. Again, the most important thing here is to understand the beat count and make sure to zoom in enough to the wave form to find the exact end and beginning of the selections or tracks.

Fading In And Out

While editing a song, you may want one to fade out while the other fades in. In order to do this, you will first need to make sure that the first track fades out and the other fades in before mixing the two. You can either choose to do the fade in and out manually, or just select the parts of the tracks you want to fade and let the software do it automatically.

Sound Forge

First select the portion of the track that you want the fade in or out to begin from. Now go to “Process > Fade > In” to make the selection fade in, or “Process > Fade > Out” to fade out. You can also choose ‘Graphic’ if you want to adjust the fade manually.

Audition

Audition has the standard automatic fade in and out feature. All you have to do is select the part of the track you want to fade in or out, and then go to “Favorites > Fade In” or “Favorites > Fade Out”, depending on your requirements.

Bonus Tip
Preview
Remember, with both software, every effect you add can be previewed by clicking on the preview button on any of the pop up boxes. If you don’t like what you hear, click Stop, change your settings and then Preview again!


Looping a track

When creating your own mixes, very often you will need to loop a track or a beat.

Sound Forge

When you select a track, or a part of a track, that you want to loop, check it by listening to it. You can make just the selection play in a loop by clicking on the Loop button located at the top left of your screen.

Only once you are sure that the selection will loop properly, and there are no audible breaks or missing beats, press [L]. This will pop up a dialog box that will ask you to fill in a few details about the loop you want to create. You can also just copy and paste your selection as many times as you want it to loop.

Audition

In Audition, you can just press [Ctrl] [P] to open the Wave Properties dialogue box, and then click on the Loop tab to see your looping options. You can also use the old trustworthy way of copy-paste to get a track to loop as long as you want it to.

Editing A Wave Form

If you know your music theory inside out, you can directly edit a wave form. This means that you will actually change the wave form manually, by using your mouse. Do not do this unless you know what you are doing, or are just playing around with a track you don’t really need anyway.

Changing a wave form is especially useful to professionals when a particular wave peak clips—there is no peak to the wave, instead it looks like a plateau. In such cases, you can adjust the wave form to a more suitable peak, rather than a plateau.

Sound Forge

In Sound Forge, you need to use the pencil tool to modify a wave. This tool button is shaped like a pencil, and placed right below the Help menu. Click on it to enable the pencil cursor, then zoom in to your wave to see the frame points. Now you can use your pencil tool to just drag the points higher or lower, redrawing your wave as you go along.

Audition

In Audition, there is no specific tool required to redraw a wave. All you need to do is zoom in to see the frame points and then drag them using the mouse. This will let you restructure your wave any way you see fit.

Mixing

Perhaps the most important aspect of audio editing is mixing. Whether you are creating your own tracks, or using readymade ones, chances are, sooner or later you are going to need to mix them in order to get the sounds you require.

Bonus Tip
Overdoing it
You don’t need to add a million effects to make a track or loop sound great. In the end, this is all about good music, and you will often come across tracks that need no improvement whatsoever. Don’t change things for the sake of change!


Sound Forge

In Sound Forge, you need to decide which two selections or tracks you wish to mix, and carefully check their beats and speeds. Even if you are mixing one part of a song with another part of the same song, beware, tempos vary. Just because it’s the same song doesn’t mean you can just copy paste one beat and place it over another—unless it’s a fixed electronica beat, as used in some trance and disco tracks.

Expert Opinion
Gilroy Valladeres,
Operations Manager,
Sound Dot Com

To help us demystify most of the basics, we got Gilroy Valladares to share some of the tricks he uses to edit audio. Gilroy is operations manager at Sound Dot Com, a professional Live Sound and Touring company that provides audio expertise for events all over the world.
Their portfolio includes the Sahara Sangeet Awards held recently at the Royal Albert Hall, London, the Gladrags Megamodel show, the CEAT Cricket Awards, War of the DJs, as well as providing expertise for live performances by bands such as Deep Purple and UB40.
Gilroy can be contacted at soundcom@vsnl.com.


To mix two tracks, open a new file, and then copy a track and paste it in the new file. Now, copy the second track or selection from the exact spot you want the mixing to occur. Go to the new file and select the exact spot in the first file from where you want mixing to occur. Once your cursor is at the correct spot, right-click and select “Mix…”. A box will pop up and ask you to specify a few settings, such as the volume of the selection you are adding and the volume of the track you are adding it to. Click OK and your tracks will be mixed. The undo option ([Ctrl] [Z]) is very handy here!

Audition

In Audition, the procedure is exactly the same as above. After you have copied the first track to the new file, and copied the second track, select the exact position of the cursor and then right-click and click on “Mix Paste…”. Here again a box pops up, with a volume control for only the selection you are pasting. Modifying the destination file’s volume isn’t really required anyway. If you do not want to mix the files, you can also choose to Insert the copied selection at the current cursor position, or even Modulate the files with Cross Fading.

The most useful bit here is the loop option. If you want your selection to be mixed and looped say, 10 times, you can just choose Overlap (Mix) and select the Loop check box and enter the value 10. This will loop your copied selection 10 times and then mix it into the current file.

Equalising a Track

One of the most important tools used to make your audio sound better is the equaliser. In order to get the exact tones you want, you need to equalise each track before you mix them or add effects to them. You can even use the equaliser to create different sounding Left and Right channels.

Most importantly, use the Preview button to listen to how your settings will sound, and also remember to use the Bypass check box to check the difference between the original and equalised track.

Sound Forge

In Sound Forge, you can open the equaliser by going to “Process > EQ > Graphic”. The equaliser pops up, and you can choose from the three types of equaliser displays—Envelope, 10 Band and 20 Band. Set the equaliser to the desired level, and don’t forget to preview your changes.

Audition

After you select a track or part of a track, go to “Effects > Filter > Graphic Equalizer…” to open the graphic equaliser. The Audition equaliser has options for 10, 20 or 30 band equaliser. It also has preset equaliser settings which can be selected from the bottom left of the pop up box. Set the equalisers and then use the preview and bypass options to hear the difference.

The Echo Effect

One of the most common effects used is the echo effect. When done with care, this can add just the right touch to your track or loop.

Sound Forge

To add an echo effect, you should first select a track or a part of a track. Now, go to “Effects > Delay/Echo”, and choose “Multi Tap…” or “Simple…”, depending on the type of Echo or Delay you want. If you choose Multi Tap, a box pops up, where you can select the Multi Tap Delay, the Number of taps, the Modulation rate, depth and Feedback, and also the Delay time. If you are not well versed with using echo and delay, just trust your ears and change the settings accordingly. 

Audition

In audition, you can add an echo effect by going to “Effects > Delay Effects > Echo…”. A box pops up with the different options for echo. You can set the Decay, Delay and Initial Echo Volume for the left and right channels individually. There is also a list of presets on the right that you can choose from. Make sure to try out the “Old Time Radio”, “Robotic” and “Taj Mahal” presets.

Flange Effects

When working with a single-track recording, such as only-vocals, etc, you can consider adding effects. The three most widely used effects for vocals and instruments are Flanger, Phaser and Wah-Wah.

Sound Forge

Go to “Effects > Flange/Wah-wah…”. A box pops up which will have three radio buttons, one each for Flange, Phaser and Wah-Wah. Select the effect you want, set the rate, depth, resonance and frequency of the effect and then preview your sound. Use the Real-time preview monitor to make changes.

Audition

Audition offers a Flange effect, and a Sweeping Phaser effect. These are accessible from the “Effects > Delay Effects” menu. Audition does not offer a Wah-Wah effect. Use the preview and bypass functions to check and re-check your settings.

Inserting Silence

When compiling a CD, or preparing a track for mixing, you may need to insert a predefined period of silence. This will let audio CD players distinguish between tracks or give you the correct spacing that is required when mixing two tracks.

Sound Forge

To insert silence in Sound Forge, go to “Process > Insert Silence…”. Add in the length of the silence you want to add, choose to add it at either the position the cursor is, or at the beginning or end of the track, and click OK.

Audition

In Audition, go to “Generate > Silence”, and enter the number of seconds, and press OK.

Converting Between Mono And Stereo

Sometimes, you may need to convert a track that was recorded in mono to stereo. Rarely would you need to convert stereo to mono, though this is also possible. Both  software have an easy way of converting between mono and stereo to give you control over your dual channel output.

Sound Forge

In Sound Forge,  just right-click anywhere and select Properties. Click on the Format tab to see file options. Here you can change the Sample rate, Bit-depth, and the Channels (Mono and Stereo). Just select Mono or Stereo, depending on which way you are converting, and click OK. When converting from mono to stereo, a box will pop up, asking you whether you want to convert to mono using only the left track, the right track, or to mix both tracks (standard). This can also be used to separate left and right tracks, to save them as separate mono files. Now use ‘Save As…’ to save the file with a new filename-for example, track1.mp3 can be saved as mono-left_only-track1.mp3.

Audition

To convert between mono and stereo, go to “Edit > Convert Sample Type…”, or press [F11]. Here you can choose the Sample Rate, Channels (stereo or mono), and the Resolution (bit rate). Make the appropriate selections and then either save as a new file or just press OK to overwrite the existing file. When converting between mono and stereo, it is advisable to keep a copy of the original recording, so always use the ‘Save As…’ option.

Recording

The easiest way to record your tracks is to connect the instrument or external device to the Line-in or Microphone port of your computer. This way you can record directly into the software, instead of using a  second software, and then importing into your editing software. Recording directly will prevent any loss in quality, and speed up the editing process.

Sound Forge

In Sound Forge, just click on the record button to get the recording pop up box. Here you can select the source (Sound card) and record from the Line-in.

Audition

In Audition, you can monitor the recording level, and select which input you want to record from. Press [F10] to see the input levels for the currently selected source, and then go to “Options > Windows Recording Mixer…”. The default Windows Recording Control box will pop up, where you can select the input device and its volume level. To record, just click on the
red Record button on the bottom left.

Synching With Video

As an added feature, you can synchronise an audio track with a video file. This will let you create better presentations or videos, as each visual event can be synched with an audio event. In order to do so, you need to be able to view the audio and video frames simultaneously while you edit. Both software allow you to do this.

Sound Forge

Go to “File > New”, and create a blank file. Insert a silence that is equal to the length of the video file—a little more in fact, so long as you remember to remove the additional blank space at the end later. Now right-click and select Properties, and click on the Video tab. Click on attach, and select the video file you want to attach.

On the top bar you will see the video displayed in frames. In order to accurately edit the video frame by frame, you will need to zoom in to the wave form you are editing or creating. Now you can begin creating and editing your audio track to fit your video. When you save your video, however, make sure you have disk space. Because Sound Forge is not a video editing tool, it expands compressed video files, and does not recompress them when it saves. Our test 10 MB .MOV file was saved as a 640 MB file after editing!

Audition

In Audition, you can use the Multi-track view to edit a video file’s audio track. Audition is much more powerful in these terms than Sound Forge. Using the Multi-track view you can just add effects and sounds to different tracks to create a much better soundtrack. You can also enhance existing soundtracks easily.

To open a video file, just switch to the Multi-track view and right click in Track 1. Go to “Insert > Video”. Select the video file from the dialog box and click OK. Audition will import both the audio and the video from the file as two separate tracks. Now you can edit the audio freely, and watch the video in real time playing along with your edited audio.

If you don’t see a video preview box when playing the file to test it, go to “Window > Video”. You can only save the edited audio back to AVI video files.

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