Tempos Differing - Playing a Song Slower or Faster
A common question I get asked is how fast 4/4 time is. The 4/4 at the beginning of a line of music doesn't indicate the tempo of a song, it indicates how many beats are in a bar (4 in this case) and which note value receives the beat (quarter note in this case). This 4/4 is what's known as the Time Signature.
Tempo is up to the player, even when playing a known song.
Take a listen to the study song "Temperature" (Tongue Block Study Song 2 http://www.bluesharmonica.com/lessons/tongue_blocking_2). Temperature is presented at a given tempo and as a student you'll commonly learn it at 30% slow, then 15% slow and then ultimately at its original tempo.
After you learn a song, it's now your song... you can play it slower, faster or at original tempo.
Place Temperature in a program like the Amazing Slow Downer and listen to it at 80%, 90%, 110% and 120% relative to its original speed and see which you like best. If you've learned this song already, go ahead and play along to these differing tempos.
The challenge for you is to keep everything proportionally the same... everything (every lick and space) either faster or slower.
Think of the song and its tempo as a balloon. The balloon represents your tempo and the graphic image on the balloon is your song. To slow down the song blow up the balloon more. Your graphic grows proportionally, making everything larger (and slower in our case). To speed up the song let some air out of your balloon and the graphic becomes smaller, making the distance of all of your notes proportionally closer together.
Hopefully this balloon analogy helps you to understand better what happens when a song is played at differing tempos.