One notable name that's missing from the list is Apple's HomePod. While it didn't move enough units numbers-wise to make the top five, the device is pricey enough to have captured 16 percent of wholesale smart speaker revenue for the quarter.

It's telling that four out of the five top devices on the list for Q2 came from Amazon and Google. These two companies are emerging as the clear winners in the smart assistant competition. The question now is which will be dominant between the two.