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Tweeter in parallel with coaxial. Does tweeter RMS need to match coaxial?


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I have 2 x 100w rms coaxial speakers powered by a 2 x 150w rms amp. The gain was set to match the lower rms speakers with a multimeter and 1k test tone. sqrt(100w*4ohm) = ac voltage.

 

I assume the coaxials are seeing close to 100w at times. When the volume on my head unit is at its max non clip point. Which is quiet often.

 

I would like to put tweeters with their own crossovers in parallel with the coaxials.

 

How many RMS will the tweeter actually see? Will I blow a 40w rms tweeter?

 

Also, the coaxial speaker's sensitivity is 90db and the tweeters are 93db. Are the tweeters going to be loud?

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It depends. No it should not blow. Tweeters are tough.  What is important is they should be 4 ohm and in parallel with the coax the amplifier will see a 2 ohm load. 

 

I don't underatand the sensitivity rating. P sure that's 1 w at 1 meter. Some crossovers have -2, 0 and +2 db. 

 

Cheers

Edited by liteblue
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Hmmm. I was under the impression the amp would not see a 2 ohm load because the tweeters are only operating at the higher frequencies.

 

Anyone know how I could quieten down the tweeters if they are too loud?

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3 hours ago, RazorRust said:

Hmmm. I was under the impression the amp would not see a 2 ohm load because the tweeters are only operating at the higher frequencies.

 EDIT!

 

I might need more research 🤔😩😫

 

Not sure now 😕 

Edited by liteblue
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No matter what frequencies pass, each channel you spoke on is seeing a beginning load of 2 ohms. Just split them tweeters from them coaxials. So, wire them 2 coaxials in parallel on one channel at 2ohms. And then wire them tweeters in series on one channel at 8ohms.

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:stupid:“How can we help you?”
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the customer isn’t always right.”

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Splitting your coaxials and tweeters and wiring your tweeters in series could be avoided and you can make your tweeters quieter with the EQ on your head unit if its EQ has multiple bands. That’s another thing to keep in mind. And if you split your coaxials and tweeters, make sure you wire/solder a non-polarized 100v 3.3 microfarad capacitor on the positive wire on each tweeter. They are called bass blockers and are small capacitors less than an inch.

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:stupid:“How can we help you?”
:guido:
“And don’t forget to tell them that 
the customer isn’t always right.”

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42 minutes ago, RazorRust said:

Here's what I read regarding the ohms: https://www.diyaudio.com/forums/car-audio/275689-tweeters-coaxials-parallel.html

 

Not wanting to hook the tweeters to the head unit or eq if not necessary. 

 

Guess I'll just order some and see what happens.

Your head unit has a built in EQ that can help you. Don’t go past flat (zero). Tune the tweeters in the negative on the higher frequency bands. And what are you gonna order?

:stupid:“How can we help you?”
:guido:
“And don’t forget to tell them that 
the customer isn’t always right.”

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