Slow practice is not slow

The objection to slow practice is always about time. There are twenty-five minutes before work, the piece is four pages, and taking it at half tempo means getting through half of it. It feels like choosing to do less.

It is the other way round, and the reason is mechanical rather than moral.

Two things get called slow practice

The first is playing the whole piece slowly, start to finish, at a mild reduction. This is pleasant and it is mostly not practice. It is a run-through with the tension taken out, and it leaves every habit in the piece exactly where it was.

The second is working a short passage at a tempo where you can hear and control every note in it, then raising that tempo in small steps. That is the thing worth defending, and when people say slow practice does not work for them, they have almost always been doing the first one.

What speed hides

Play a scalar run at performance tempo and you will hear a run. Play the same run at half that and you will hear that the third note is early, the seventh is louder than the rest, and there is a gap where the hand changes position.

Those things were there at tempo. Speed did not remove them; it removed your ability to notice them. The audience notices, in the sense that the passage sounds untidy without them being able to say why.

There is also a limit on correction. If a passage is running at eight notes a second, no amount of concentration lets you decide anything about note six while note five is sounding. The hand is running a movement it already knows. Practice is the process of choosing which movement that is, and choosing has to happen at a speed where there is time to choose.

The movement you rehearse is the movement you get

This is the whole argument and it is not a research finding, it is what every teacher watches happen in a studio every week. Your hands learn what they repeat, including the flinch before the shift and the extra squeeze in the thumb. They do not know which repetitions were meant to count.

So the useful question is not "how much did I practice" but "what did I practice, exactly". Ten fast repetitions of a passage with a lurch in it is ten rehearsals of the lurch. Five slow repetitions without it is five rehearsals of the passage you want. Under tempo is simply the speed at which you get to choose.

Sixty percent, with the pitch where it was

This is the part a score in a browser can do that a metronome cannot. Here are eight bars of guitar at 90. Load it, set the tempo down to 60 percent, and listen: the pitch does not move.

If that sounds unremarkable, it is worth remembering what slowing music down used to cost. A record at half speed dropped an octave. A tape machine at half speed did the same. Generations of players learned solos in the wrong key and transposed them back by ear, and slow practice against a recording meant practicing against a sound nothing like the piece.

Playback that holds pitch while it changes tempo means under-tempo work no longer sounds like a different piece. You can play along with it. You can check your intonation against it, which you cannot do with something a fifth flat.

Loop the bars, not the page

The second thing to do with a score you can control is stop playing the parts that are already fine.

Select the two bars that fail and loop them. The loop turns the count into something the room does for you: you play the fragment, it comes round again, you play it again, and the decision to stop after a good one is the only discipline left. That is roughly the whole method from an earlier post, automated.

How slow, and for how long

Slow enough that it is easy. If you are not sure whether it is easy, it is not.

Then move in small increments and stop when the quality drops rather than when the time is up. A passage practiced carefully for eight minutes is further ahead than the same passage practiced anxiously for thirty, and the eight minutes leaves you able to do something else with the rest of the session.

Twenty-five minutes before work, spent at 60 percent on two bars and one transition, is a real practice session. Twenty-five minutes of playing the whole piece at a tempo you cannot control is a warm bath.

About the time it takes

Open an interactive score from your own library and the player counts the time while it plays. Once you have more than a minute, the button that saves it as a practice session against that piece becomes available. Counting stops while the tab is hidden, so leaving the page open and going to make coffee does not turn into forty minutes of practice you did not do.

That is the only thing MakesPerfect does with slow practice that a good pair of ears would not: it removes the argument at the end of the week about how much work went in, and it does it without asking you to estimate anything.