Slow decline of SDA CRS's

mderning

I've had a pair of CRS's (blade/pin) since I purchased them new around 1989 or so.

A year ago a tweeter went out so I replaced both with SL2000s.

I've been working on a CD project lately and when I initially brought the mixes home was shattered at how poor they sounded on my stereo.

So, before taking it out on my engineer, I hauled in a pair of R50s I use in my office. Bingo. Way better, imaging great and mixes very similar to studio playback. Phew.

So, obviously my CRS's have been in slow decline and since I don't listen to music in my living room as much as I used to, I didn't really notice. Suspected it, but let it go.

I've got plenty of power, have switched drivers around, etc, to see what might be faulty. Drivers are functioning correcly from what I can tell.

I would love to restore these speakers to their original state. There's nothing quite like them. Where do I begin?

BlueMDPicker

Welcome to the forum!

Here's a good read to start you off (I don't know how much disparity there is between the CRS and CRS+ xovers, but still good information):

http://www.polkaudio.com/forums/showthread.php?t=40577

mderning

BlueMDPicker wrote:

Welcome to the forum!

Here's a good read to start you off (I don't know how much disparity there is between the CRS and CRS+ xovers, but still good information):

http://www.polkaudio.com/forums/showthread.php?t=40577

Thanks for the welcome and thread.

I don't think I want to play around with the current crossover - don't have the time especially when I'm not sure that the results may be. Why not replace crossovers? Any downside to that, other than cost? I notice replacements are available from Polk......

BlueMDPicker

If the crossovers are available (just a head's up, but some items listed are no longer available), it's worth a shot. Personally, I'd upgrade the existing resistors and caps on the originals before buying replacements (money better spent.) Can you describe the loss in sound quality with a bit more singularity?

Quick suggested checklist:

Driver, passive radiator, and tweeter frames well sealed to cabinet? Does gently pushing in on the driver cones cause movement in the passive radiator?

Replace the external fuses (if the CRS has them) and clean the contact area for them.

All polarities correct (tweeters and drivers)? You mentioned you replaced the tweeters. **** happens.

Phase correct at amp for each channel? Again, **** happens.

mderning

BlueMDPicker wrote:

If the crossovers are available (just a head's up, but some items listed are no longer available), it's worth a shot. Personally, I'd upgrade the existing resistors and caps on the originals before buying replacements (money better spent.) Can you describe the loss in sound quality with a bit more singularity?

Quick suggested checklist:

Driver, passive radiator, and tweeter frames well sealed to cabinet? Does gently pushing in on the driver cones cause movement in the passive radiator?

Replace the external fuses (if the CRS has them) and clean the contact area for them.

All polarities correct (tweeters and drivers)? You mentioned you replaced the tweeters. **** happens.

Phase correct at amp for each channel? Again, **** happens.

All of the above are OK. I'm very methodical and pretty good at debugging problems.

As for a description of the problem, imaging. Play the same material on the R50s and there it is. Play it on the CRSs and there it ain't. Couldn't have a clearer test than my mixes. I come home after listening to the studio's Genelec 1032As all day and listen thru the R50s and the info is pretty much all there but the CRSs are blurry.

I'm not that concerned with money. My time is more important at this point and I just want to return the speakers to their former glory. I really don't want to chuck them.

amulford

I second ugrading the original crossovers. You will actually exceed the Performance of their former glory.

Plus you'll have the oppurtunity to reseal all of the drivers to bring cabinet performance back up to spec.

What's the setup like?

F1nut

The electrolytic caps in your crossovers have reached the end of their life. Besides that, they are inferior to film and foil caps, so it's time to upgrade your crossovers.

Since you have the CRS+ (only the CRS+ have the pin/blade cable) you might consider doing the 4.1TL upgrade. I can say from doing it myself that the results far exceed the original sound.

hearingimpared

Welcom to the club.

Don't have anything here for you. Listen to those guys, they know!

BlueMDPicker

Maybe he just needs one of these?

hearingimpared

BlueMDPicker wrote:

Maybe he just needs one of these?

No really . . . what the hell is it?

DarqueKnight

mderning wrote:

I've had a pair of CRS's (blade/pin) since I purchased them new around 1989 or so.

A year ago a tweeter went out so I replaced both with SL2000s.

Tweeters usually don't just "go out" unless they are overdriven by clipping. What amp were you using when the tweeter went out? What amp are you using now?

If the tweeters were overdriven a year ago, the tweeter protection polyswitch has probably gone bad. It would be a good idea to replace both of them. They go bad with age. Their end-of-life is accelerated if they are tripped numberous times. The polyswitches are available from Polk Customer Service free of charge.

Also, if the tweeters were damaged by a clipping situation, some of the other components on the crossover board could have been damaged also.

F1 and others have provided good advice about replacing the electrolytic capacitors in the crossovers. They have a typical life of 15 years. Your CRS+'s are 17 years old.

mderning wrote:

So, obviously my CRS's have been in slow decline and since I don't listen to music in my living room as much as I used to, I didn't really notice. Suspected it, but let it go.

mderning wrote:

I've got plenty of power, have switched drivers around, etc, to see what might be faulty. Drivers are functioning correcly from what I can tell.

I would love to restore these speakers to their original state. There's nothing quite like them. Where do I begin?

As others have advised, looks like crossover upgrade surgery is required. No way around it. Even if new crossovers are available from Polk, I do not advise going that route because the components on the replacement board are going to be 17 years old. Modding crossovers is a pain, but the rewards far exceed the cost and inconvenience.

schwarcw

hearingimpared wrote:

No really . . . what the hell is it?

Snake oil! Mike is in a playful mood!:D

Mike, what's up with the "Mt. Wannahockalugi"? Too much cough syrup??

BlueMDPicker

schwarcw wrote:

Mike, what's up with the "Mt. Wannahockalugi"? Too much cough syrup??

After our dinner at "Rory and Trendi's", I consider myself fully initiated into the Polk aquarium tribe. My tribal name shall be "Cusses-While-Driving".

mderning

As others have advised, looks like crossover upgrade surgery is required. No way around it. Even if new crossovers are available from Polk, I do not advise going that route because the components on the replacement board are going to be 17 years old. Modding crossovers is a pain, but the rewards far exceed the cost and inconvenience.

Sigh. Nothing is easy, is it?:( I didn't stop to think the crossovers are new old stock.

Power source when it went out and same used now is a Denon DRA-685 receiver. 100 watts/channel. I don't play music loud enough to blow tweeters. At 55 I save my ears for loud guitar playing :rolleyes:. But I hear you, that's been my experience with tweeters, I've never seen them go bad w/o an event. Curious thing is only one tweeter went, the other appeared to be fine even though I changed it out. In my past experience, tweeters tend to blow in pairs. So I don't know what the deal is.

At any rate I appreciate all the quick and useful info. I will make use of it. I'll report back when either the speakers are back in shape or blown to heck.

DarqueKnight

It could be that the polyswitch of each speaker is in a different state of decline, hence, one speaker's tweeter was protected while the other one blew.

The polyswitches become more resistive with age and with the number of times they are tripped. If your tweeters are being "strangled" by the polyswitches, this, in addition to bad crossover capacitors, could affect the imaging.

heiney9

BlueMDPicker wrote:

Maybe he just needs one of these?

I had alittle chuckle at this phrase in the description of this item. I am really missing on some quick money making opportunities. I wouldn't bea able to sleep at night but I might be rich

"The Clock doesn't affect the audio signal anywhere in the audio system - including audio components, cabling/wires/house wiring or acoustic waves in the room."

So how does it make things sound better if it doesn't affect the singal or the sound wave? LOL

hearingimpared

mderning wrote:

In my past experience, tweeters tend to blow in pairs. So I don't know what the deal is.

I disagree. I have driven many amps to clipping (unintentionally of course) and have heard the tweeters pop. I had to replace one channel's tweeter but not the other on a few different speaker systems that I had. One great tweeter blowing LP is the Pyotr Ilyich Tchaikovsky's 1812 Overture, Telarc digital. That cost me tweeters on a pair of RTR 300s, RTR 600s and Polk SDA/SRSs. All three incidents were one tweeter on the right channel. I know we are supposed to learn from our mistakes but this LP was a killer when the cannon blasts occured even at lower listening levels. That could be why I'm hearingimpared! LOL

DarqueKnight

mderning wrote:

In my past experience, tweeters tend to blow in pairs. So I don't know what the deal is.

hearingimpared wrote:

I disagree. I have driven many amps to clipping (unintentionally of course) and have heard the tweeters pop. I had to replace one channel's tweeter but not the other on a few different speaker systems that I had.

I agree with your disagreement. It is highly possible for only one tweeter to blow in a stereo pair of speakers if each speaker receives a different signal. If the music is mixed with big bass in the left channel and lightweight midrange and treble in the right and then the amp clips...well, you get the idea.

DarqueKnight

heiney9 wrote:

So how does it make things sound better if it doesn't affect the singal or the sound wave? LOL

Placebo effect? Wishful thinking? The flashing lights induce an altered state of mind?

heiney9

DarqueKnight wrote:

Placebo effect? Wishful thinking? The flashing lights induce an altered state of mind?

All of the above

BlueMDPicker

DarqueKnight wrote:

Placebo effect? Wishful thinking? The flashing lights induce an altered state of mind?

I'd sure like to hear Professor Irwin Corey's thoughts on this one.

mderning

DarqueKnight wrote:

I agree with your disagreement. It is highly possible for only one tweeter to blow in a stereo pair of speakers if each speaker receives a different signal. If the music is mixed with big bass in the left channel and lightweight midrange and treble in the right and then the amp clips...well, you get the idea.

Yeah, after I posted that I realized it was just experiential and not very scientific. Of course you can have a situation where only one is damaged. I witnessed that. The previous experiences I had involved teenagers. Where I was lucky if anything still worked. Ah, to be young and deaf again.

BobMcG

heiney9 wrote:

So how does it make things sound better if it doesn't affect the singal or the sound wave? LOL

DarqueKnight wrote:

Placebo effect? Wishful thinking? The flashing lights induce an altered state of mind?

Yes,:) yes:D and yes.:eek: Plus, it's just the soft warm feeling you get from the sheer comfort in knowing they're in the room with you doing the mysterious thing they do, and that you spent good money on them.:o Why, of course they work.

Man, we're really missing the gravy boat you know it?

mderning

Just noticed the sticky regarding the compendium. I'm not allowed to send private messages yet. DarqueKnight, can you private message me the info I need to obtain a copy? Thanks.

DarqueKnight

PM sent.

schwarcw

mderning, with a little patience and maybe a few bucks those CRS+'s will sound good if not better than they did when new. Many of us here have had the same issues with the SDA's at one time or another:( This Forum is a great source of help and advice for audio lovers in all levels. Good luck and let us know how it turns out.

Carl

mderning

schwarcw wrote:

mderning, with a little patience and maybe a few bucks those CRS+'s will sound good if not better than they did when new. Many of us here have had the same issues with the SDA's at one time or another:( This Forum is a great source of help and advice for audio lovers in all levels. Good luck and let us know how it turns out.

Carl

Yeah, looks like I've got a project on my hands. But it sounds like fun and I'm excited about getting the CRSs back up to specs. I miss them. I'll definitely report back. And I agree, this is a great forum. Nice folks.