Do passive X-overs go bad over time?

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=54344
Printed Date: May 11, 2025 at 5:48 PM

Topic: Do passive X-overs go bad over time?

Posted By: Cpuneck
Subject: Do passive X-overs go bad over time?
Date Posted: April 21, 2005 at 5:03 AM

I have a pair of JL audio components in my truck powered by a Fosgate 250x2. The speakers are over 5 years old and I've found when playing my music loud there is a "compression" effect on my upper frequencies. It's like your adjusting the trebble all the way down. Now if I turn it down a little you can hear the upper frequencies come back. I've changed the amp thinking it was that (Pioneer Premier 250x2) and it did the same thing. :(

Replies:

Posted By: DYohn
Date Posted: April 21, 2005 at 8:17 AM

Speakers will generally wear out - especially when played at high volume - long before crossovers. But yes, it is possible a capacitor in your crossover has a higher DCR (or ESR) than it should due to age. If this was your problem the effect is unlikely to change with volume level, though. Much more likely the problem is your head unit or your amp is clipping, or the speaker is simply being over-driven from too much power.

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Posted By: Cpuneck
Date Posted: April 21, 2005 at 9:07 PM

OK, please give me some advice on testing as I've already tried replacing the front amp with the same results. I can replicate these results regularly. I'm trying to figure out what is broke. I'd have a hard time saying it's the head unit as it works just fine otherwise. Thanks for the help. posted_image

Posted By: DYohn
Date Posted: April 21, 2005 at 10:09 PM

Is this happeneing on both right and left? If so it's most likely that nothing is broken, but your amp or head unit is clipping, or you are over-powering the speakers. In either case they will soon blow if you keep operating like this. How was the gain set? Do you know the point at which your HU clips? What's the RMS power rating of the speakers and of the amp?

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Posted By: dpaton
Date Posted: April 22, 2005 at 6:36 PM

It might also be your ears. They do that. It's one of several things that fall into a phenomena known as "threshold shift", and it's an indicator that you should turn it down. Ask me how I know.

-dave

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Posted By: Cpuneck
Date Posted: April 24, 2005 at 7:34 PM

Well I'm sure it's not my ears as I run a board connected to a system documented at 129db posted_image

Always sounds good! Now back to my truck. I believe the speakers are ~175watts ea. and have been in the truck as long as the other components. When everything was new, this didn't happen. It's easy to reproduce and to experiance (other people have) I can turn up the volume and 30-55sec later it sounds like I'm moving the sliders down on the Eq starting with the highest frequencies and working my way down. When it finally settles out it sounds like there is no 1k and above posted_image

. As soon as I turn down the volume, you start hearing the return of the lost ambiance. Also my Sony ES MDX-8500 (I believe) is hooked up completely passive. The internal amp has NEVER been used as I've always had seperate amps hooked up for front, rear, and sub channels. Thanks

Posted By: Cpuneck
Date Posted: April 24, 2005 at 7:37 PM

Opps, Yes both front channels do this at the same time.

Posted By: DYohn
Date Posted: April 24, 2005 at 7:54 PM

Try this. Swap the RCA connections on your front and rear channels but leave the speaker connections alone. If the problem moves to the rear it is your head unit. If it stays in the front, it's either the amp or the speakers. If it stays, try swapping the speaker connections AND the RCAs (swap the front channel amp and rear channel amp.) If it moves, it's the amp, if it stays, it's in the speakers - or crossovers.

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