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    loopable wav


    I have a question. If I find a song I like here how can I make it loopable?
    Why is some effects made loopable while other are not?

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    Some clips lend themselves to looping better than others.

    For a sound to be loopable, the end of the clip must line up with the beginning of the clip. Depending on the sound, it may need to match in tempo, in timbre, and/or in volume.

    Many “ambient” sounds are good candidates for looping. Depending on the sound, they may not really need any special processing to loop. If the volume is reasonable stable but the timbre varies quite a bit through the clip, you can simply append the entire clip to itself to double the size as often as necessary to make it as long as you need to. Nobody will ever notice the splice.

    Here’s one of my ambient clips that can be looped indefinitely using that method:

    http://www.freesound.org/samplesViewSingle.php?id=117410 (Children Ambiance)

    In fact, there are several splices in that clip where I cut out some specific children’s voices because I thought they would be too recognizable. I bet you can’t even tell where they are. I also added some reverb (to make the room seem larger and to further “muddle” the individual voices) and I applied a compressor effect (several times) to create a consistent volume throughout. All those tricks aid the loopability of the clip.

    If there is a rather constant timbre throughout the clip (like a hum or a drone), it may not loop using that method because the splice would be noticeable. If that’s the case, you have a couple of options. If you are using the clip as a background for a video scene, you can place the splice at a point in the video where there is already another loud noise or a scene or a camera change. By doing that, the splice may be hidden.

    Another trick that I have used is to “fold” the clip on itself. This takes some advanced knowledge of audio editing in Audacity or GoldWave or some editor like that. Make a copy of the entire clip and then “reverse” it. Paste the reversed image to the end of the original. That way the end of the clip will seamlessly match the beginning of the clip. Here is a clip that I used that trick on:

    http://www.freesound.org/samplesViewSingle.php?id=78522 (Rain on a Roof)

    The second half of the sound is actually a reversed version of the first half, which is why the end of the clip seemlessly matches the beginning.

    Of course, that works only on clips that sound virtually the same forwards and backwards, like rain or running water. (I tried it on the “children ambiance” clip above with less-than-desirable results. They ended up sounding like aliens.)

    Another category of loopable clips is where there is a fixed tempo or rhythm to the clip. In that case, you can use audio editing software to carefully trim the clip so that the end of the clip has exactly the correct amount of space as between each “event”. That way, you can append the clip over and over to create a loop as long as you need it to be. (If you trim it incorrectly, you’ll get a little hiccup or limp at each splice.)

    Here are two clips that I trimmed to be perfectly loopable:

    http://www.freesound.org/samplesViewSingle.php?id=78563 (Clock Ticking)
    http://www.freesound.org/samplesViewSingle.php?id=81827 (Windshield Wipers)

    I hope that helps.

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    Snap to zero crossings is essential.

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    But the wav posted here is very long and hence the file is very big. Do you know lightning bug? Its a android app that plays ambient music. This is not big in size so I guess they use only 5-10 seconds loops. Is it possible to loop this short loops without the listener noticing it?

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    misogenisnt
    Snap to zero crossings is essential.

    Good catch! I have "snap to zero crossing" set as the default in GoldWave, so I tend to forget it's there. But if it isn't set, you can sure tell the difference.

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    Thesting
    But the wav posted here is very long and hence the file is very big. Do you know lightning bug? Its a android app that plays ambient music. This is not big in size so I guess they use only 5-10 seconds loops. Is it possible to loop this short loops without the listener noticing it?

    The size of the clip is irrelevant. What matters is how well the end of the clip matches the beginning of the clip. The distance between the beginning and the end could be 1/10 of a second or ten hours. It doesn't matter.

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