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Passive X-over

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=28823
Printed Date: May 15, 2025 at 11:29 AM


Topic: Passive X-over

Posted By: gtchida
Subject: Passive X-over
Date Posted: March 22, 2004 at 12:01 AM

My system will consist of a Rockford 851s powering an adire shiva 12 utilizing the on-board crossover.

I am using an 851x to power 2 midrange, 2 mid bass, and 4 tweeters with the combination of the on-board x-over and caps / coils. My questions are...

1. Should I wire the midrange and tweeters to the "front" portion of the amp and the mid bass alone on the "rear" or should I use a different configuration?

2.  Should I match the crossover impedence to the speakers or to the overall impedance per channel? Currently, all my drivers are 4ohm.

Any other suggestions are welcome...

Thanks,

Gary




Replies:

Posted By: DYohn
Date Posted: March 22, 2004 at 8:28 AM

1.  You could do this, it's up to you.  I'd simply build the proper 3-way Xover and use two channels of the amp.

2.  Design your crossover for the impedence of the drivers.  Choose your X-points, then determone the proper cap/coil values based on the total impedence load of the drivers you are using.  A properly designed x-over will never let the amp see less than the impedence of one speaker at a time.  BEWARE of using two tweets (for a total 2-ohm load) and 4-ohm mid & bass.  The tweets will be at a higher relative volume level since they will present a lower impedence load.  You will need to incorporate attenuating resisters to adjust for the excess brightness.  I also recomend using a zobel network across your bass driver.





Posted By: gtchida
Date Posted: March 22, 2004 at 9:00 AM

Thanks DYohn, can you tell me about the "attenuating resisters to adjust for the excess brightness".

Gary





Posted By: DYohn
Date Posted: March 22, 2004 at 10:28 AM

Here's one of the best tutortials I know about.  Attenuation is discussed in this. Be sure to use good quality components in the X-over, not cheap stuff from Radio Shack.  Use audio grade, especially for the caps.

https://sound.westhost.com/lr-passive.htm

Cheers!






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