XO Wave: Edit Softening

(a)

(b)

(c)

Figure 1. An abrupt transition from silence to a very loud sample, as shown in (a), can produce a popping noise. This can be eliminated by manually trimming the region to a "zero-crossing" (b), or by creating a fade (c). However, manually eliminating such pops is usually not necessary in XO Wave because XO Wave has a built-in edit-softening feature which will use similar techniques to eliminate pops automatically.

Edit Softening is a feature of XO Wave that automatically removes discontinuities that often occur at edit points. For example, if you place a region onto a track and trim it to a point where the waveform is high, such as in Figure 1a, it creates a discontinuity between the region and the surrounding silence. If this were played back as is, it would create a loud popping sound because of the discontinuity between silence and the first sample in the region. This popping sound is not only annoying, but it is also potentially damaging to speakers and your ears because it contains some very high frequency content. Edit softening is XO Wave's way of automatically eliminating these horrible sounds.

How Edit Softening Works

The problem of discontinuities at edit points can be fixed manually by either trimming the region to the nearest "zero crossing", as shown in Figure 1b, or by creating a fade, as shown in Figure 1c. Obviously, it may be hard to trim to a zero crossing if you have a stereo region with left and right channels that vary significantly, but even when it does work, it takes time away from more important tasks.

Instead of having to waste time tweaking each transition manually, XO Wave removes the discontinuities automatically during playback. Your waveforms won't look any different, but they'll sound much better because any ear-splitting pops will have been removed.

Although you can fine-tune the settings, the defaults work like this:

• When XO Wave starts playing back a region, it plays silence until it reaches a zero-crossing, at which point it starts playing back at full volume.
• When XO Wave gets close to the end a region, it fades the end of the region out, using a short, linear fade.

Turning Edit Softening On and Off and Fine-Tuning

In general, the defaults have been found to work well in virtually every situation. However, there may be some cases where you prefer turning it off or tweaking it's settings. Edit softening may be turned off on a per-track basis by clicking the Edit Softening button in the Track Control Panel. By double-clicking this button, you will see a window (pictured below) which allows you to fine-tune the settings. For example, instead of using the zero-crossing technique for removing discontinuities at the start of a region, you can use a fade-in of a selectable length.

Don't Try This at Home

Finally, it's worth mentioning that some musicians, such as the Postal Service, have used the popping sounds created by abrupt transitions as a special effect. You can do so as well, but I suggest you try and keep the levels of the pops low so as not to damage anything or cause ear strain. One option for reducing the side-effects without eliminating that pop is to set the Edit Softening feature to use very short fade ins, such as around 5 samples.