High pass filter question

If you mean that on the tweeter, which is half the crossover, the answer is yes.

 

What are you looking to do? The PA cab would (should) have an LPF in it as well, if you're looking at moving some parts over.

 

The HPF would be calculated for the tweeters impedanve at the crossover frequency regardless of the woofer impedance. I assume you mean 1.5khz, not 15. That calls for a quality mid/high horn and driver, a 3rd order filter, not a single cap, and a 2nd order LPF for the woofers.

 

Not much above 15khz that is usable.
Consider FM Stereo Radio, it has no audio content above 15khz
the Delta are going to cut off well before 15khz
A midrange horn with a real crossover and a tweeter with a real crossover would be best.

 

At the very least you need to use a 3rd order highpass, and the woofers must be low passed as well.

When you want to blow your horn midway through its first gig.

 

Some bass cabs do use 1st order, and it defines cheap. You basically can't get any cheaper. They set them up at 5-6khz. It makes them sound very harsh, causing players to turn them at least down if not off, thereby saving the tweeter, at least temporarily. Yet, there are still countless threads about blown tweeters, and Talkbass might be 2% of all the blown tweeters out there. IMO, if they do it that way, they shouldn't waste any time or money doing it at all.

Somebody with more experience than I would have to help with your calculations.

 

Passive Crossover Slopes