Today we’ve changed how our playback speed selector works: you now specify the speed in BPM (beats per minute) instead of a percentage, if you’re using synthetic playback. “Real” recordings, such as MP3s or videos, still use a percentage.

The idea here is to better reflect how musicians think about tempo. If you’re learning a fast piece of music, starting slowly and building up tempo, then it’s more natural to think in BPM than an arbitrary percentage.

It’s also a bit presumptuous to grant a specific tempo “100 percent” status, in cases where you don’t have a reference recording you’re trying to mimic. Often there’s no absolutely right or wrong tempo.

At the same time, lots of musicians have grown accustomed to using percentages, and we think this makes sense when trying to learn from specific reference recordings. That’s why we’ve changed our speed selector to work differently depending on the context:

• If the slice is synced with a real recording, then you change speed in percentages (the right example).
• If the slice doesn’t have a real recording, or you’ve chosen “Synthetic” playback, then you change speed in BPM (the left example).

At the risk of complexity, we think this dual-purpose interface strikes a nice balance for the two learning approaches. Let us know what you think.