In this paper vibration energy harvesters based on coupled oscillators were compared to single degree of freedom (SDoF) systems. The harvester concepts were compared based on two cases: 1) a signal where a combination of two harmonic motions is continuously present and 2) a signal where the harmonic motions are alternating. Three configurations of the coupled oscillator harvester concept were presented and optimized for maximum power output. It was found that a coupled oscillator with two electromagnetic dampers performed equally well as an array of two SDoF systems. Coupled oscillators with only a single electromagnetic damper performed worse than the SDoF array. A prototype was built to validate the simulations and good correspondence between simulations and experiments was found.