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I was thinking of using a passive highpass filter for the tweeters. Not sure about the brand, but all the one's I am looking at are 8 ohm. Is there a way to design a passive highpass crossover (more of a protection circuit) that would drop the impedence down to 4 ohms instead of 8 ohms? If this doesn't work, what about wiring 2 pair in parallel (1 pair in kicks and 1 in the Apillars). Use some soft of passive blend knob to switch between each pair). That would give me a 4 ohm load and be able to use tweeters in kicks, while still having a pair in the dash to avoid the "rainbow" effect.
 

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I think I'm understanding your question. First, tweeters are generally very efficient when compared to other drivers. That being said, an 8 ohm tweeter will very likely run just fine alongside a 4 ohm driver. Check out npdang's article on speaker sensitivity, and varying impedances.

Next, an 8 ohm speaker is an 8 ohm speaker. You can use all the resistors in the world, and drop the impedance of the load seen by the amp to .00000000000000001 ohms, and that speaker will still be 8 ohms. The extra resistors in parallel would just be wasted power. The ONLY difference between a speaker and a resistor is the fact that the speaker provides a return on your power investment, and that is musical output. A resistor just causes a voltage drop across it, with no benefit.

That being said, no there is no way to make an 8 ohm tweeter into a 4 ohm tweeter. Also, just because the tweeters and driver are different impedances doesn't mean they can't work together.

Lastly, using two separate tweeters like you mentioned wouldn't be a bad idea at all. CDT does this with their "Image Enhancement Kits". It's a combination of filters and L-Pads. If you need more info, let me know. I use this kind of method frequently when designing passives.
 

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Discussion Starter #3
MiniVanMan said:
I think I'm understanding your question. First, tweeters are generally very efficient when compared to other drivers. That being said, an 8 ohm tweeter will very likely run just fine alongside a 4 ohm driver. Check out npdang's article on speaker sensitivity, and varying impedances.

Next, an 8 ohm speaker is an 8 ohm speaker. You can use all the resistors in the world, and drop the impedance of the load seen by the amp to .00000000000000001 ohms, and that speaker will still be 8 ohms. The extra resistors in parallel would just be wasted power. The ONLY difference between a speaker and a resistor is the fact that the speaker provides a return on your power investment, and that is musical output. A resistor just causes a voltage drop across it, with no benefit.

That being said, no there is no way to make an 8 ohm tweeter into a 4 ohm tweeter. Also, just because the tweeters and driver are different impedances doesn't mean they can't work together.

Lastly, using two separate tweeters like you mentioned wouldn't be a bad idea at all. CDT does this with their "Image Enhancement Kits". It's a combination of filters and L-Pads. If you need more info, let me know. I use this kind of method frequently when designing passives.

thanks!

I would appreciate more information on using multiple tweeters. Only reason I am considering that is because I have heard putting tweeters up on the dash/ Apillars with mids in the kicks causes too many phase problems. If I knew I could adjust enough using phase and time delay, I would just stick with 1 pair up high and leave out the ones in the kicks completely.
 

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Why do you need a 4 ohm load? You can't change the driver's impedance, but you can change the load the amp sees.
 
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