crossover death

nms

When crossovers die / go bad, how fast does it happen? Is it a slow, gradual degradation in sound quality, or is it a sudden "one minute it sounds great, the next minute it sounds like it's playing through broken glass" type of deal?

Thanks!

Face

Are you sure it's not a tweeter? You can swap from one cab to the other. Otherwise, you could yank the crossover and inspect it.

nms

Right now it's just a little tickle of "crackliness" in the left tweeter on some high passages. Not all the time, and part of me thinks I'm imagining it because it's so transitory and faint. So I haven't even begun to diagnose it.

I was just wondering how quickly this type of thing normally happens, because this wasn't present a week ago

ben62670

Poly switches are going bad. Call Polk CS and mention you are a member. Polkies get them free.

F1nut

Crossovers can go bad slowly or in a New York second. However, I agree with Mike and Ben, it's more likely one of those two issues.

dorokusai

They can also not go "bad" in a lifetime...one never knows. The problem is probably pretty simple.

Which loudspeaker are we talking about?

F1nut

Depends on how one defines a lifetime. The odds are against any electrolytic cap lasting more than 20 years as they do dry out.

ben62670

dorokusai wrote: »

They can also not go "bad" in a lifetime...one never knows. The problem is probably pretty simple.

Which loudspeaker are we talking about?

Polk's

dorokusai

I had a console Telefunken from 1956, at Polkfest 2005 that sounded pretty nice. Maybe you didn't get your ears on it but I used it for two more years until I parted it out to someone in Japan. I didn't notice any bloated caps or components that needed replacement.

Oh well, YMMV.

dorokusai

ben62670 wrote: »

Polk's

Thanks rocket scientist....he has two pairs. Did you look at his system or just blurt out whatever came into your head?

ben62670

dorokusai wrote: »

Thanks rocket scientist....he has two pairs.

HeHe. I'm funny damn it:D:p:D

dorokusai

He's got some crazy setup....I'd love to hear it That's a stack allright.

Let's take bets on which xover now....I'll bet one goat that it's the Monitor 10's, in the end.

nms

Thanks guys.

For those of you who asked, it's the 2As that I'm talking about right now (doro, you lose a goat! ). I know for a fact that one of the 10Bs has a bad x-over, but right now those don't get played a lot for a variety of reasons.

Thanks again for all the help. I'll see if it gets worse over the next few weeks.

heiney9

Just to put my .02c in.

X-over's 90% of the time gradually loose there original specs. Mostly due to the use of electrolytic capacitors which good ones have a typical useful life of 15-20 years. The cheap ones used in Polks and many other mass produced electronics most likely will have a shorter life cycle.

The second thing to consider is if you are not the original owner of the speakers the X-over may have had it's life cycle significantly shortened by previous owner abuse.

Always check the basic things first like swapping tweeters, cables (both speaker and interconnect) and a very common issue with Polk's are the poly switches. If you change the poly switches inspect the x-over visually. I found a burnt resistor on one of my 5B's.

My 5B's just never sounded right from the beginning. Bass was anemic, vocals were sucked out and the highs were shrill. Once I rebuilt the x-overs and put in RD0's they were excellent. Not every 5B will have such a dramatic improvement but mine did; I suspect they took some abuse over the years.

After 15-20 years of service if you are noticing some issues with your speakers and you are a tweaker and like tinkering then I always recommend updating the x-overs. I have never heard of someone who updated/upgraded x-overs say it wasn't worth it. All in all there is a significant change for the better.

H9

dorokusai

Where did that 90% figure come from exactly? Just wondering. In case I missed an issue of the local audio magazine.

heiney9

dorokusai wrote: »

Where did that 90% figure come from exactly? Just wondering. In case I missed an issue of the local audio magazine.

Pulled it out of my hairy a** based on my personal knowledge and experience over the past 25 years in this hobby, working in the business, as well as my interest in electronics/design and all the information I've amassed in 25 years. Feel free to disagree.

Point being that it is a gradual thing, not one day it sounds fine the next it sound like crap. But once in awhile something happens where one day it sounds fine the next it sounds like crap. It may always sound fine to you.

H9

dorokusai

Ok, so essentially it means very little. Just checking. You rule.

dkg999

What H9 fails to mention is that his original 5B's were found setting at a local flea market, with only the passive radiators intact. I had extra mid/woof drivers and SL2000 tweeters setting around, so I gave the guy $20 for them as they were in OK cosmetic shape. So they could of had some previous to me owner abuse! They actually sounded pretty good after I stuck the drivers I had in them, but nowhere near the level of SQ that they are at now with the improvements H9 made to them!

heiney9

dorokusai wrote: »

Ok, so essentially it means very little. Just checking. You rule.

Hey just adding my .02c to the discussion. You don't agree, that's fine. You are the one with the attitude and the need to always RULE. Be sure to take your meds, you'll feel better.

BTW, my opinion has just as much validity as yours. I know you think you rule, but in the end it's just a friendly discussion. Some of us are friendlier than others at times however.

H9

gij801

So is there a way to check if a cap is within tolerance of its original value to know whether you should update it or not?

F1nut

Absolutely. Set your DVOM to uF and test away.

dorokusai

heiney9 wrote: »

Hey just adding my .02c to the discussion. You don't agree, that's fine. You are the one with the attitude and the need to always RULE. Be sure to take your meds, you'll feel better.

BTW, my opinion has just as much validity as yours. I know you think you rule, but in the end it's just a friendly discussion. Some of us are friendlier than others at times however.

H9

Absolutely but I try not to make sweeping generalizations regardless of personal belief.

ShinAce

Be careful testing caps. Another test to add is to use a battery and resistor, now insert the cap as a DC blocking cap and see if there is a leakage current. Leaky caps need to be replaced. If there is no current flowing with this setup, and the capacitance reads within spec, you're ok to continue using it. Another way to do such a test is to charge the cap with a battery(you need the cap out of circuit for this) and then hook up an LED and resistor to see how long it lasts. Now you charge the cap and wait, say, an hour before doing the same LED test. If it was brighter and or lasted longer the first time, the cap is leaking.

There's nothing wrong with replacing these small and inexpensive components if you can afford it and just want to rest easy.

nms

There's nothing wrong with replacing these small and inexpensive components if you can afford it and just want to rest easy.

I probably will towards the end of this summer, depending on what other projects I start up.

Thanks for all the input guys, it's what makes this place great.

dorokusai

It will be a fun project. Post pics!