I was in discussions with another user of this forum about the CPC and WLE piezo and thought the best way to show the difference is to simply measure and display the results.
Both single 1016 piezo's where measured with pink noise with the exact same signal level and measurement mic sat in the same location.
This is a very quick and dirty plot carried out in my garage, but the only purpose was to compare the top end roll off of the cheaper WLE piezo.
CPC piezo:-

WLE piezo:-

You can clearly see the massive drop in the upper freq's, it starts around 5k.
Dave