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
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?
The amplifier power is not the issue because you're the one in control of how far you turn it up. If you use a lower powered amp, you'll run into distortion earlier and if you push it, that might blow tweeters quicker.
Would I not be able to use resistors to reduce the risk of blowing the tweeters while still maintaining a high level of power to the sub?
If the tweeters are louder than needed to match levels with the bass driver then yes, an L-pad composed of a couple of resistors is the standard way of adjusting that in a passive crossover.
Is see so if I’m connecting the 5 piezo tweeters to the high pass section in parallel and they’re around 50w rms each will I need to limit the power based of the sum or average of these rms values?
Limit? How are you planning to do that?
Assuming you set them up in proper balance, the only limiting there is will be your choice on how far to turn them up.. unless you have a protection circuit?
Assuming you set them up in proper balance, the only limiting there is will be your choice on how far to turn them up.. unless you have a protection circuit?
By limit I was referring to the l-pad circuit previously mentioned by David. Would I not need to use on of these if I could make the total rms for all the tweeters the same as the rms of the sub? And would this go the same for finding a horn driver
You are talking about reducing the level to protect the tweeters. Won't that make them sound bad if they're not at the right level? Perhaps I'm missing something...
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?
No. I’m saying that resistors make them quiet or loud compared to the woofers. Only one amount is right.
Forget about power for now, it’s not important in that way.
Forget about power for now, it’s not important in that way.
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?
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?
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.
They'll need a certain amount to get loud for your use. Either your amp can do it or it can't.
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?
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.
They have a capacitive impedance. I don't know how you plan to cross, but you'll need to know at that stage.