How to Upload Music to Audacity and Overlap Voice

April 14, 2022 Post a Comment

Switching tracks all of a sudden in your audio/video projects can exist really jarring for the audience. Crossfades tin can aid make natural-sounding transitions between audio tracks, and y'all tin can really take advantage of them if you lot know a little nearly how audio works.

What is a Crossfade?

Odds are you know what a fade is, though maybe not past name. When an audio runway starts with silence and the book rises up out of nowhere, that's called a "fade-in." When a runway slowly lowers its volume until it's nothing but silence, information technology's called a "fade-out." How "sharp" a fade is directly involves how much volume is lost or gained over what flow of time. Sharper fades happen rapidly while duller or steadier fades take a long time. This is what a fade-out looks like visually:

A fade-in looks like.

A crossfade is essentially doing both simultaneously to ii split up tracks. The first track slowly fades out and the second fades in, simply instead of there being silence in between, it happens concurrently. It usually sounds like y'all opened the door to another room with different music, then went through information technology and airtight the door behind y'all.

Why is it Useful?

Many songs employ fading techniques to keen effect when starting or catastrophe, or at item parts in the song. The same goes for video; information technology's useful to exist able to fade in to a crowd'due south cheer, or fade out of an original audio source in favor of narration of some kind. Crossfading is valuable because it allows these changes to happen quickly without being jarring, without introducing silence, and while sounding polish and more than natural. DJs often utilize this technique while matching beats of ii unlike songs to produce a continuum of sound, while editors oftentimes use crossfades (as well as fade-ins and fade-outs) to make the introductions of dissimilar sound components audio less "sudden" and more than natural.

Y'all tin can grouping crossfades into three vague categories, and each sounds very different from the others.

Mid: Each track is linearly faded. Y'all tin download a brusk sample track hither: mid crossfade. Visually, it looks similar this:

linear crossfade

You can see that the volume increment/decrease looks steady. Depending on the volume of the original tracks, this sounds more or less even.

High: The faded-out track starts fading slowly, and so picks up speed equally time goes on. The faded-in track, on the other hand, picks up book fairly quickly and that increase of volume slows down over a period of time. Yous can download a short sample runway here: loftier crossfade. Visually, information technology looks like this:

high crossfade

The volume changes expect similar bulges hither, with the effect that the both tracks have a high volume through the duration of the fade, and there is still some abruptness to it.

Low: The faded-out runway drops its volume pretty quickly and the speed of this drop slows downwards over a period of time. The fade-in rail starts gaining volume slowly merely it picks upwardly speed equally fourth dimension goes on. You can download a curt sample track hither: low crossfade. Visually, it looks like this:

low crossfade

The changes here wait similar concave cuts. For the elapsing of the fade, both tracks take a reduced volume until the original track is almost completely gone. The effect feels almost like a lull (merely lacking complete silence) and the volume so builds upwards quickly over again after, well-nigh like a swoop.

When the two tracks crossover, their volume builds. For mid-level crossfades, at halfway through the transition the book of each rails is half. Low-level crossfades are beneath one-half volume halfway through the transition, and loftier-level crossfades are above half-book halfway through the transition.

Audio Differences in Crossfades

Audio is measured in Bels, or more commonly, as fraction of that unit: decibels. Human hearing is very sensitive to acute changes in sound. Simply like how we can hear very low frequencies (like twenty Hz) and very high frequencies (like 20,000 Hz), we tin hear very soft sound and very loud sounds. In fact, our ears have a sensitivity from ane to 130 decibels, which is to say that the loudest sound you can hear is roughly 10 trillion times loader than the softest audio you can hear! As such, what appears to be a "linear" alter in volume is actually logarithmic. In crossfades, if y'all want to mess with the rate of change of volume, yous need to more aggressively modify it. Information technology helps to see things visually.

Linear Crossfades in Audacity

In Brazenness, it's piece of cake to add linear crossfades. Align the ii tracks you want to crossfade in the timeline, either by editing or by using the fourth dimension shift tool. When y'all're lined up, select a portion of the track you want to fade out. Become to Effect > Cross Fade Out.

And so, in the adjacent runway, select the portion you lot desire to fade in. Go to Effect > Cross Fade In.

You can delete the residuum of the commencement track if yous're done with it. Be careful with the rail that you're fading in, though, as deleting it will motion it back to the beginning. You lot can either use the fourth dimension shift tool to bring information technology dorsum to where it needs to be, or amend withal, just convert the start office of the runway to silence.

silence beginning

Crossfading High or Low

Making high or low crossfades isn't automated in Audacity. I mode to easily practise it requires the use of the Envelope Tool.

envelope tool

The Envelope Tool volition allow yous to change the volume of any runway without really changing the amplitude. As the actual sound wave isn't changed, the source file volition remain untouched. Yous can add together multiple points to further shape the necessary change. Later selecting this tool, click on your track, and drag to change the level of volume.

enveloping for a fade

Each click volition add a new handle in the form of a white dot that you can move. Merely manually shape the bend to about what we described above. Of class, your track may have different needs. If your runway's volume itself changes, and then you lot tin can compensate or ignore information technology. As always, do what sounds right.

Crossfading has a variety of uses for both audio and video editing. Depending on what blazon of crossfade you practise, you lot'll be able to achieve a diverseness of effects for unlike purposes. Now that y'all know how crossfades piece of work, you tin choose which one works best in your projects. Later all, information technology's all about choice isn't it?

Note: The music used in the sample tracks is by Talvin Singh; "Traveller" and "Butterfly" from the album OK

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