The [Em,C,G,D] chord progression spans musical genres in its popularity and use. After many years of collecting songs that use it (or a transposition of it, e.g. [Bm,D,G,A]), I decided to demonstrate these songs' similarity by mixing them together... and so the "Same Chord Progression" project was born.
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BACKGROUND
If two songs have the same chord progression, you can mix them together, provided you can time- and pitch-shift them so that they occupy the same point on the "tempo vs. pitch" plot. By just resampling the song, you change both tempo and frequency: if you speed up the song so its length is half of what it was, you double the frequency, and it sounds like chipmunks singing. Hence, resampling changes both tempo and frequency... it moves the song along the curve f*T = Constant, where f and T are the frequency (Hz) and tempo (sec per chord progression) of the song. Unless both songs have the same constant, you can't get a good mashup with resampling. However, many audio-mixing programs have the capability to shift time or frequency independently from the other. Examples include Adobe Audition, Sony Sound Forge, and Audacity (free). For this project I used Adobe Audition, and found that I could generally time-shift by 75%-130% and pitch-shift by +/- 2 halfsteps without too much distortion. This amount varies by song, of course. The ability to shift a song to an arbitrary point on the tempo/pitch plot enables someone with plenty of time on his hands to make some very interesting song mixes.
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VIDEOS
SCP Mashup - Main Menu
http://www.youtube.com/watch?v=fhqAXjEK0LMThis video is the main menu for a number of "Same Chord Progression" (SCP) Mashups. Use the YouTube annotations to select pairwise mashups, or click the Walkthrough button (upper right) to hear snippets from all the songs.
SCP Mashup - Song Walkthrough
http://www.youtube.com/watch?v=XImK6XrzI3kThis video demonstrates that, even though each of the songs has a different tempo and key, it employs the same chord progression as all the others. The x-axis is tempo (measured in "seconds per chord progression") and the y-axis is frequency (measured as the base note of the first chord in the progression). The robotic arm indicates the song currently playing, the tempo (sec per chord progression), frequency (Hz), and chords in the progression. The song itself is indicated by its cover art.
Mashups
Be sure to check out the various mashups that all use this chord progression:
Hammerhead Hell (Offspring, Sum41, Cynic Project)
http://www.youtube.com/watch?v=UCS1OglVM-4Save Tonight Whenever (Eagle Eye Cherry, Shakira)
http://www.youtube.com/watch?v=lTacJDCLNzkLife's Lost Apologies (OneRepublic, Bon Jovi, Josh Vietti)
http://www.youtube.com/watch?v=ctqeQFXY_-oIn Another Side (Red Hot Chili Peppers, U2)
http://www.youtube.com/watch?v=xiD7z04LBSYI Hope You Build a Mystery (Bloodhound Gang, Sarah McLachlan, Cynic Project)
http://www.youtube.com/watch?v=KljPZINcEoA===========================
MUSIC CREDITS
Hammerhead -- Offspring
Grid II -- The Cynic Project
The Hell Song -- Sum 41
Save Tonight -- Eagle Eye Cherry
Otherside -- Red Hot Chili peppers
I Hope You Die -- Bloodhound Gang
In a Little While -- U2
Building a Mystery -- Sarah McLachlan
Apologize -- OneRepublic and Timbaland
It's My Life -- Bon Jovi
Lost Without You -- Josh Vietti
Whenever, Wherever -- Shakira
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OTHER SCP SONGS
My Oh My -- Aqua
My Skin -- Natalie Merchant
Rods and Cones -- Blue Man Group
Shooting Star -- Flip and Fill
Telling Stories -- Tracy Chapman
Tonight and the Rest of My Life -- Nina Gordon
You -- Switchfoot
(less info)
