Tempo: It's complicated...
On the surface, tempo is a simple count of how many beats occur in a single minute of music but it’s much more than that.
It’s about the speed, the attitude and the feel of a song. It can tell you if you need to warm up before you play or if you can simple walk up and get it on.
In terms of sheet music, it has yet another role: readability.
Sound & Vision
Oftentimes a song can sound really fast but actually be in a slow tempo. This is very common for rock and metal music (many Slayer songs sound REALLY fast but on closer inspection they’re actually at a tempo that’s half what they sound like).
How does this relate to sheet music?
If a song is actually at 88bpm but you hear is at double or even double-double that, writing out the really fast parts can leave things looking utterly garbled on the page.
For example, this is the exact same riff at 88bpm and double that at 176bpm.
At 88bpm the entire riff takes up a single bar and is a mixture of 16th and 32nd notes that are really hard to read. It’s very difficult to visually isolate the downbeats and orient yourself in the riff (and this is the riff without any accents!).
While the actual tempo IS 88bpm, doubling it and writing it out at 176bpm makes the whole thing so much more intelligible.
Drums, drums drums...
A lot of people assess the bpm of a track by the drums.
This is logical enough as, generally, they’re the time-keepers of the piece but, with some forms of music, metal and rock especially, the drums can be playing a lot faster than the rest of the band and so taking tempo from them is misleading.
Let’s take a simple 16th note riff at 120bpm.
A riff like this is quite common in heavy rock and metal. It sounds like this:
Now, let’s add in some drums.
Pattern 1: Half-time Feel
Pattern 2: On the beat
Pattern 3: Double-Time
Pattern 4: Lombardo!
Which all sounds like this:
If we look at the drum tab here, when things are at Lombardo speed they’re getting pretty hard to read due to how crowded they are.
Imagine that Lombardo speed pattern with fills all over it at 32nd and 64th note values! I’m feeling sick even contemplating it…
The solution? Anything above a Double-time feel, double the tempo to halve the values on the page! The Lombardo pattern is now written out, at 240bpm, the way the Double-time pattern was at 120bpm…
This provides plenty of breathing room for fills to be written out and makes it much simpler to read.
In terms of the riff itself, that can stay written out at 120bpm because the actual core tempo hasn’t changed but in order to make what’s written down easier to read for drums here, we have to do some sleight of hand.
So when you hear a drummer say, “yeah, that song’s at like 265bpm!” it’s not but it also kind of is for them…