Possibly good new tweeter?

[John Carr]

I e-mailed Kenneth Fritz awhile back about tweeter suggestions and he told me that Planar tweeters are the best of the bunch. I have been wondering if I should buy some, and then these came to my attention: Foster E100T10.
https://www.parts-express.com/Foster-E100T10-Ribbon-Tweeter-8-Ohm-279-468?quantity=2

They recently went on sale as well. Does anyone have any idea if these are good/worth buying?

 

[homebrew]

With a 6kHz crossover point, they would have to be used in a three or four-way speaker system.

 

[John Carr]

With a 6kHz crossover point, they would have to be used in a three or four-way speaker system.

I have a four way diy system.

 

[JRhoBurton]

I have a pair of the Foster leafs used in the Speakerlab Super Seven. The design looks very similar. Yes, they must be crossed high and steep. I do active at LR4 and I don't recall hearing anything better In the range from about 6500 up.