Crossfading 101

The purpose of the first Dance Project of the year was to learn how to cut digital audio in Audacity. The purpose of Dance Project 2 is to learn how to crossfade instead of making hard cuts on a piece of music of the student's own choosing.  Let me tell you, this was a struggle for some students.

Some students learned that they need to listen to a piece of music differently when crossfading.  Instead of listening to the lyrics, they need to listen not just for the beat ("boom...boom...boom...boom"), but also for the count ("...5, 6, 7, 8, 1, 2...").  The technique I have learned to use comes from working with WLA's Dance and Cheer Teams over the years.  They have what they call "8-Counts": generic sideline routines choreographed to groups of eight beats that they can adapt to fit any song that is played by the Pep Band at a home football or basketball game.

I use the concept of "eight counts" when cutting music to help me line up the end of one cut with the beginning of another cut.  The procedure I use and teach my students is this:

1. Leave extra music (at least 4-5 beats) at the beginning and ending of each cut so that you have music to overlap to make a good crossfade.
2. Find the last downbeat of the first cut (beat "1") and line it up vertically with the first downbeat of the second cut (also beat "1"). 
3. Decide whether you need to either silence audio (Cmd-L) on either track at the overlap or if it works better to fade out audio on the first track and fade in audio on the second track (like in the picture above).
4. Check your work by listening through your crossfade, tapping your foot to make sure the beat is steady and counting eight-counts to make sure "1" (the downbeat) fall on the strongest beat.

Want to learn more about crossfading in Audacity?  Read the article "How to Use Crossfade in Audacity for Seamless Transitions Between Audio Tracks" from How-To Geeks.

EDITED 10/9/13 11:54 am – Rebecca raised a good point in her comment below: I never talked about "Christmas trees" in this blog post.  When I first start teaching my students to see beats in a waveform, I encouraged them to tip their heads to the right and see the wave as a Christmas tree laying on it's side: the bottom branches of the tree are the beginning of the beat, the narrowest part of the wave is the top of the Christmas tree. (Do you the "Christmas tree" in the crossfading picture above?) Thinking this way, I can tell my students to always cut entire "Christmas trees" (up to, but not including the bottom branches of the next "tree") and they will always select entire beats in their editing.

When should you use the "Christmas tree" method?  I use it every time I select audio, because I will always select a full beat.  The challenge in crossfading comes when you are working with music that has lyrics.  Crossfading lyrics gets messy because you can hear the same singer singing two different words at the same time.  If it can't happen on stage that way, I try to never let that happen in my editing. So, I'll do a hard cut, using the Christmas tree method) on whichever track needs the lyrics cut out and use a fade on the other track.