The engine is quite noticeable in this video - it sounds like a drill maybe?? The video is sped up 800x .. In real life, the hum is very deep and hard to hear but you can feel it in the steering wheel.. Pretty interesting though..
This is an interesting video of the Japanese Insight, with sound-monitoring/recording devices placed under the hood. The video runs through different drive modes and their corresponding under-hood engine sounds. These recordings were done with relatively low (3 bar) HV battery charge, so...
@insightfully posted related video awhile back of what it sounds like under the hood while the Insight is running.