Build your internal clock with SUS4 Time Trainer

For SUS4 Time Trainer and SUS4 Metronome6 min readUpdated 29 September 2026

Playing in time with a click is not the same as having good time. Most players lock on to the metronome, and the moment it stops (a count-in that ends, a band with no click, a quiet bar in a song) the tempo starts to wander.

SUS4 Time Trainer measures that. You tap or play along, it scores every hit against the beat, and then it switches the click off and checks whether you can keep going on your own. Here is a 15-minute routine that uses it properly.

The short version

Warm up at 100 BPM. Start a session at the default 100 BPM and tap along for a minute to get a baseline Hits score.
Read Mean before Hits. Look at Mean: a negative number means you are ahead of the beat, positive means behind. Correct the tendency, not just the score.
Turn on Mute practice. Switch Mute practice on. The click plays 4 beats, then goes silent for 2. Keep tapping through the gap.
Lengthen the silence. When your drift in the gap stays small, raise the silent count, up to 8.
Move the tempo. Repeat at a slow tempo such as 60 BPM, which is harder than it sounds, then at the tempo of a song you are learning.

What the numbers mean

Each tap is scored against the nearest beat. It counts as a hit if it lands inside the hit window, which is ±10% of one beat, kept between 25 and 80 ms. At 100 BPM that is ±60 ms. At 140 BPM it tightens to ±42 ms. The subtitle tells you the current window.

Hits (for example 12 / 13) and the big percentage tell you how often you were inside the window. The two numbers underneath are more useful. Mean is your average offset: negative means you are rushing, positive means you are dragging. RMS is how much you scatter around that average. A player with a Mean of −3 ms and an RMS of 23 ms is centred but inconsistent. One with +20 ms and 8 ms is very consistent, but late.

SUS4 Time Trainer on iPhone during a session at 100 BPM: 92%, 12 of 13 hits, mean −3 ms, RMS 23 ms, a 30-session accuracy graph and the TAP pad. — A session at 100 BPM (App Store screenshot): 12 of 13 hits, slightly early on average (−3 ms), with 23 ms of scatter.

The 15-minute routine

Minutes 1 to 3: tap along at the default 100 BPM with the click. Don’t chase the percentage. Watch Mean and see which way you lean.

Minutes 4 to 8: switch on Mute practice. The click plays four beats and then goes silent. The default gap is 2 beats, and the screen shows "KEEP TIME" with a countdown while it is quiet. Keep tapping through it. When the click comes back you get a result: Drift (how far you had wandered, in ms) and Jitter (how uneven you were). When the drift stays small, add another silent beat, up to 8.

Minutes 9 to 12: drop to 60 BPM and do it again. Slow tempos leave a long gap between beats to fill with your own pulse, which is where most people drift.

Minutes 13 to 15: set the BPM (40 to 220) to a song you are working on, and finish there.

Use the Challenges to push the tempo range

The star button opens Challenges, which run you through a set of tempos and ask for a minimum accuracy: Warm Up (60, 80 and 100 BPM at 80%), Locked In (80 to 160 BPM at 95%), Iron Tempo (100 to 180 BPM at 90%), Full Range (60 to 180 BPM at 85%) and Sprint Mode (120, 140 and 160 BPM for 20 seconds each at 90%). They are a good weekly check that your time holds up at tempos you don’t usually practise at.

SUS4 Time Trainer on iPhone after a session at 140 BPM: 88%, 14 of 16 hits, mean +3 ms, RMS 28 ms, with a ±42 ms hit window. — At 140 BPM the hit window shrinks to ±42 ms (App Store screenshot).

Take it to the metronome

Once your drift in the silent gaps is consistently small, take the same idea into real practice with SUS4 Metronome. Its Mute every setting drops the click out for a set number of bars (up to 16), and the Practice trainer under Programs raises the tempo from a start BPM to a target every few bars. That is a good way to take a difficult passage up to speed without losing the time you have built.