Introducing Tachyo

Tachyo is a new metronome for iOS. It’s my first new app in 15 years, and also my first project after going fully independent earlier this year.

Now, you may ask if there aren’t already enough other metronome apps out there. There certainly are many. But, as is so often the case when I look for software, I haven’t found any of them to be quite satisfactory.

Beyond the obvious functional requirements (and my personal ones are actually quite basic), there are a number of usability and quality requirements that I think tend to get ignored.

The main one of these is being able to set the speed quickly but also precisely. This turned out to be the central design problem for Tachyo. When choosing from 200 possible bpm values on a touchscreen, efficiency and precision are seemingly conflicting requirements: fast selection would require having all options close together, but then they’d be very small, making it hard to target a precise value. Any apps that address this usually offer multiple mechanisms, each optimised for either speed or precision. The nice thing about a wheel is that it offers a natural way to choose how you want to make that trade-off, in a single control: near its centre you can turn it quickly, or you can fine-tune its rotation near the edge.

However, this insight was only the start of overcoming the challenge. Creating a digital wheel that behaves in a sensible way is actually rather difficult. On the one hand, you want it to feel “natural”. On the other hand, there is no such thing: people will perform gestures in a virtual UI which have no meaningful equivalent on a physical wheel. Tachyo’s speed wheel required a completely custom implementation, and I explored seven distinct approaches before finding a set of calculations that produced what I felt was the right behaviour. I hope you like the result.

Some tips: try flicking the wheel from near its centre to spin it very fast. You can also tap on the left/right half to decrease/increase the speed by 1 bpm at a time.

Here are some other features you may enjoy:

• A quick way to set an accent every 2–12 beats.
• A varied set of 16 pleasant, high-quality sounds.
• A comprehensive menu of traditional tempo markings.
• When running Tachyo in the background, you can pause and restart it from the lock screen or Control Centre.
• A choice of colour schemes so you can personalise the UI to your taste.

Tachyo is available for iOS 16.4 or newer in the App Store. Please consider leaving a rating to let me know how you like it and to help others make a decision. Also feel free to email me if you have any questions or feedback.