Expansion Module for Teenage Engineering OP-Z. The Rumble is the second of the OP-Z expansion modules. It allows you to feel the music you are making. It does this by providing the haptic feedback needed to shake the OP-Z. Using high-definition vibrotactile feedback and psychoacoustic research. It provides you with deep sounding subs with a frequency response of 10-150Hz which is designed maximise the impact from the ZM-2. It's efficient on your battery too as it doesn't put too much stress on it. As well as being great for getting a feel of your music - it features a silent metronome that helps you stay in time when performing live.