So how did drummers find the tempo of a song ... back before there was a "Tap" feature on electronic metronome? I personally would try to guess the tempo, get it in the ballpark, then spend the next 5 minutes or so trying to dial the metronome to the exact tempo. Very frustrating! Well, here's a fantastic little method I learned from Nashville studio session drummer, Paul Leim.
Let's say you are working with an artist, and he/she is counting off the tempo of where they want the song to be performed at. You don't have a metronome with the "tap" function, and you don't have the five minutes it used to take me to find the tempo ... what do you do? If you've got a wrist watch with the "stop watch" function ... you're good to go!
Have the artist play, and time the length it takes for them to play six beats (pulses). It doesn't matter what the meter or time signature is ... just start the stop watch on one of the down beats and time the music for six beats, stopping on the seventh beat. Now you have the length of time it takes to play six beats of the song. So what's the tempo?
To figure out the tempo use this formula:
60 divided by the "measured time" ... multiply by the number of beats/pulses measured. If it took the artist 4.495 seconds to play six beats of the song, the tempo would be 80 bpm. So now you know what to set your metronome to!
60 divided by 4.495 equals 13.348
13.348 multiplied by 6 equals 80.088
80.088 translates out to be 80 bpm
I personally like to measure the length of time it takes to play six beats because four beats just seems to be too short, and the artist may start to get impatient if you take forever ... so six beats works well for me. If you wanted to time ten pulses rather than six, you would take 60 divided by the "measured time" it took to play ten pulses, multiplied by the number of pulses measured, which in this case is 10 ... and now you have your answer!
Another way to figure out tempos is to use your computer if you don't have a stop watch function. You can even import a WAV file ... such as a drum loop ... find out how many pulses (beats) are in the loop, then find out how long it takes for the loop to play. 60 divided by the length of the loop, multiplied by the number of pulses or beats in the loop ... and you've got your tempo marking!
