If the built-in speaker in your OP-Z isn’t really cutting it, Teenage Engineering has a solution. The rumble module is the second optional expansion for the company’s portable electronic instrument - following the Oplab CV/gate add-on - and is described as a “built-in haptic subwoofer”.
Given the name and description, we’re guessing that the ‘rumble’ experience is similar to that which you’d get from a video game controller; Teenage Engineering says that the device enables you to “feel your music”.
We’re also told that rumble uses “high-definition vibrotactile feedback and psychoacoustic technology,” and has a frequency response of 10 - 150hz. As well as offering subwoofer functionality, it also features a silent metronome mode to keep you in time.
Find out more on the Teenage Engineering website, where rumble can be purchased for £69.