If you've ever attempted to edit sounds or create new sound files from exsisting recordings this tutorial will be very helpful.
Have you tired to loop a sound sample but suffered from an intermittent clicking sound? If so then continue to read and I'll explain in the best way possible to loop sounds.
Looping sounds is not only based on the actual audio of the clip but it also contains a lot of visual reference too. Programs such as Goldwave, Sony Sound Forge and Adobe Sound Booth all offer a visual reference to the sound clip as well as the audio reference via the play button.
In this example I will use Goldwave being as it contains a lot of features, with an all round ease of use. To download Goldwave visit
http://www.goldwave.com/.
Once downloaded, run the program and simply drag the source recording into the main screen area of Goldwave. This will then open that file and show a visual reference of the audio file.
Again in this example I will attempt to loop an engine idling sound. Firstly, use the section tool to select a section of sound that you would like to use. If you're looping an engine, as I am, you will need to ensure that the rhythm of the engine sound is believable and realistic.
First make sure you have the following setup.
So taking away the consideration that it may have an intermittent sound just hit the YELLOW play button and listen to the rhythm. Once you are happy with
the rhythm copy that section and paste it as a new file.
I will not explain how to do that as the program is very simple to use.
Once you have pasted the new file (that was sected from the source recording) you should be able to play the file directly via the yellow button again, if you was lucky you may not have any interference what so ever. However 80% of the time there is interference, so this is where I will explain how to remove this.
Why does it have interference? - this is simple because the ends of the sound clip do not match, therefore producing a 'clicking' or 'clunking' sound between the ends.
If you are placing this sound file inside a simulation program such as RailWorks it will have the same effect or possibly, dramatically worse because of the sound engine inside the program.
There are two ways to prevent interference, below is the first way.
To insure that the ends of the files match we need to zoom into the visualisation of the sound clip. If you have a mouse roller simply roll the mouse to zoom in and continue to zoom in until the sound visualisation is slight jagered and squared.
The below image clear shows this. Also notice the highlighted red line showing the center line of the sound clip.
As a guide line we can use the center balance line of the sound file to help us match the ends together. In this case they are slightly above the center lines. Its probably best to insure that they sit directly on the center lines for both the left and right channels of the audio. Simply select a section of the audio (whilst zoomed in) and delete them until the audio lines are sitting directly on top of the center line. Repeat process at the other end of the sound clip.
After which the sound should loop OK. If not is a case of trial and error to insure it does, but the bottom line is either ends need to match, visually.
The other way to do this without deleting sections of the clip (if using a small clip for example, like mine) you can simply do the 'select and reverse' trick. To do this select the whole clip, then copy and paste into the same file. When you paste the new section DO NOT DESELECT, you need to click the 'Effects' menu at the top and then hit reverse.
After you've done (depending on the ryhm of the sound) you should have a nice looping audo clip. Below is how mine turned out.
