Soundlab P115CV rebuild

I recently bought some pretty banged up soundlab p115cv’s of Facebook marketplace and got some decent use out of them before I managed to blow all the drivers in them. I’ve tried to find replacement drivers so that I could use the old crossover but haven’t had any luck finding them online. This has lead me to want to design my own crossover and buy new speakers to fit into the cabinets. I need to get 6 tweeters (5 piezo style and 1 horn) and a subwoofer. I want the speaker to work with a thoman amp that puts out 2x350w at 8ohms and was wondering where to start the crossover design to complete this goal. Should all the speakers have the same impedance and be connected in parallel with resistors to reach the desired ohm raiting? How should I tackle the wattage, would the total rms raiting if the drivers need to equal that of the amp?
Any help would be greatly appreciated
 
Having a read of that article has been very helpful thank you! Part of it suggest using an oscillator and amp to test the speakers impedance is this necessary or will I be able to use ZMA and FRD files directly from the manufacturer to inform my crossover design?
 
I am only just getting into the world of speaker design so my lack of terminology may be the confusing factor here 😂. Are you saying that if each of my piezo tweeters is rated at 50w rms and I have 5 making 250w rms when in parallel then I won’t need to fit a circuit like the L pad to protect them?
 
Ah so a resistor in parallel would just reduce the db level of the drive and bring it back to a suitable range for it?
Then with the power should I be thinking about this after the speakers have been made. So then what are the key factors to think about for the crossover is it just impedance and db response in the given frequency range?
 
diyAudio Moderator
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Ah so a resistor in parallel would just reduce the db level of the drive and bring it back to a suitable range for it?
I'm not sure I get your point here. Resistors in parallel are just another part of the circuit. On the other hand, you cant just use them and expect it to work without considering other parts of the circuit.

By the way, your piezos do not work as normal tweeters do in the electrical sense. You can't just use a regular crossover for them.
 
With the resistor I was just referring to what you had said before about reducing the level of the tweeter to make them not as loud as the woofer. And how do the piezo tweeters operate differently would it be more simple to go for standard tweeters for simplicity sakes? And would this be the same if I were to get a piezo horn as well?
 
diyAudio Moderator
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With the resistor I was just referring to what you had said before about reducing the level of the tweeter to make them not as loud as the woofer.
Ok, then it has nothing to do with your amplifier power or the driver power. It has to do with how loud they get comparged with each other when fed the same drive, quiet or loud doesn't matter as it will mean the same resistance.

how do the piezo tweeters operate differently
They have a capacitive impedance. I don't know how you plan to cross, but you'll need to know at that stage.