Fun with Inversion


Evening.I intended to create a long blog last time, but sadly, I am still working on it. It intends to be a continuation on The Driving Force of Music, where I explain how certain instruments and progressions lead up to some of the emotions we feel. As an amateur in music studies compared to my music major friends, I hope I'm able to at least convey my thoughts so that it makes sense for everybody!Today's blog is a short one, and it deals with a fun topic of sound waves in music. As we all know, music is conveyed by multiple sounds placed at certain times and rhythms that we then interpret with our minds. We hear music everywhere: from your car's radio, to your phone's music library, to scenes within a movie. Most of the time, we listen to music accompanied by vocals. It's always fascinated me how certain combinations of instruments and vocals can harmonize together to create something truly beautiful. Listening to each track separately makes it even all the more amazing, by seeing how creative the human mind can get. Be it singing a specific harmony, playing supplemental chords to the melody, or adding that extra pizzazz with percussion or sound effects, it's amazing how these collections of sounds can be interpreted as "music."Have you ever been curious as to how you could separate the vocals from a song? There are ways to minimize vocals from a song, but how can we accomplish the opposite? There's a fun trick dealing with inverting waves. It's actually really simple, and only requires a few things: a music editing program, the original song, and the instrumental version of the song.Korean and Japanese music tends to contain albums that have instrumental versions of the most popular songs at the end, so I'll be using those as my examples. I'll also be using Audacity, which is a free music-editing program.The first step is to load the program with the two songs. In this example, I'll be using IU's popular song, "Good Day."Inversion1First looking at it, we notice two sets of waves: one for the original song, and one for the instrumental. Both look fairly identical, and of course, that's expected! In order to achieve as much vocals as possible, we must put these waves on top of each other whenever both play at the same time. Then, we use a simple trick of inverting one set of waves to cancel out the other. Think of it in math terms. If you have a positive number, and you add its negative equivalent, you get zero. That's exactly what we're doing here!In order to get these waves to match dead-on, we must zoom in all the way to the millisecond level, as such:Inversion2I like to highlight a distinct pattern in the waves just so I can match up the waves a bit better. Notice how in this picture below, I'm looking for a distinct curve that I can match with the other wave easily. From there, I just shift them until they're as close to identical as they can be.Inversion3The last step is to simply invert the instrumental track. Now, you'll notice that the two tracks will almost look like mirror opposites of each other:Inversion4Then, just listen to the song. This isn't perfect in any way, and volume discrepancies/quality of each audio file/timing are all factors that can damage having a pure, vocal-only track. But it'll definitely get you in the right direction!Here's the final result. The first track is the original song, second track is instrumental, and the third is the inverted result.Original[audio mp3=""][/audio] Instrumental[audio mp3=""][/audio] Vocal[audio mp3=""][/audio] Again, not a perfect science, but it's a good starting point. Here's another sample I did over the song Hikaru Nara by Goose house. This one came out much better. It's awesome getting a chance to listen to the harmonization of the vocals in this one.Original[audio mp3=""][/audio] Vocal[audio mp3=""][/audio] All it takes are a few songs and free software. Try extracting your own vocals and see what you get!Until next time,Corey