Adjusting the volume is the most frequent action when playing or working on music. But Dutch & Dutch speakers don't ship with a physical volume control.
Some users rely on external devices for this: a streaming device, an external gain controller, a mixing desk, etc. Not everyone though; a good example is people who play music using streaming services.
For these users, an app without a decent volume control is like shipping a heavy, very expensive brick. Which is why the volume control is front and center in the app.
The existing volume control had a few discoverability and usability issues that needed fixing:
None of these actions are obvious. There are no visual cues that tell users how to complete any of them. And because the Dutch and Dutch home audience skews a bit older, there's a strong need for the app's interface to feel as familiar and obvious as possible.
The circle with zero affordances was leading to support tickets.
A summary of the changes I made (the video explains in detail):
Why not a typical volume slider? It’s very easy to move a simple volume slider from 0
Too easy, in fact.
Dutch & Dutch speakers go loud. Not just wake up the neighbors loud; ear-damaging loud, if turned up too quickly while sitting too close. We needed some inertia built into the volume control, and we needed to prevent large volume jumps with a single gesture.
A synthesizer's pitch wheel has obvious use cues and some friction built in. Mimicking a control from the real world that had proven itself over decades felt like a natural fit.
The other details like the indicator line, the haptic feedback, and the larger than life dB level while dragging were somewhat inspired by !Boring's World's Most Satisfying Checkbox; the volume control is the most used control in the app. It should be extremely obvious. But not boring!