At $US800 ($1,125) for the small version, Seaboard's Roli keyboards — with their touch sensitive squishy keys that let musicians enhance their performances while they play — aren't cheap. But taking advantage of the iPhone 6s' 3D Touch feature, there's now a free Roli app that provides a similar experience on your phone.
NOISE 5D works on older iOS devices as well, but performances will be limited to tap and swipe gestures on its virtual keyboard. To take advantage of the pressure-sensitive features that the Roli's keyboards are known for — like shifting pitch by pressing harder, or creating vibrato with just a finger wiggle — you'll need to be using the app on a newer iPhone with 3D Touch.
Despite being free, Roli hasn't skimped on the features in its app. You have the option to display 13, 17, or 25 keys on screen at a time, you can tweak the layout with additional modulation controls, and it supports MIDI over Bluetooth so you can use it for actual performances.
In the event that the 25 simulated instruments included don't provide the exact sound you're looking for, there are also add-on sound packs available for just a few dollars. If you bought an iPhone 6s or 6s Plus and have been disappointed with the lazy implementation of 3D Touch features to date, you finally have a reason to feel good about upgrading your phone.