Please help with SDA CRS's

armistad

Hey guys, I'm a brand new visitor to this forum, and I was hoping someone here could help me troubleshoot my newly acquired set of SDA CRS's. My dad just recently gave them to me after he got some new speakers.

I had heard great things about the speakers, but unfortunately when I set them up I experienced some problems. To be honest, I'm not speaker-savvy at all, so I do not really know where to start with this problem, and I was hoping someone here could help me troubleshoot a little bit. Here's whats happening-

The Left speaker of the set seems to work perfectly, but the Right speaker sounds very faded and seems to only play certain tones of the song. I took the cover off the front of the Right speaker, and it seems that only one of the woofers (out of the 2 tweeters? and 2 woofers?) is playing music. If I put the balance on my receiver all the way to the Left, I can hear the song clearly, but if I put the balance on my receiver all the way to the Right, the sound is very dull and there are no high tones.

If any of you could help me figure out how to fix these (if I can), I would really appreciate it.

Thanks


If there is anything else I can clarify about my problem, please let me know. (And someone once said it might be the interconnect cable, but I have that plugged in)

BSUfbfan

Well, the CRS's don't have bi-amp inputs, so that eliminates a jumper issue, so the best thing to do would be to pull out the two tweeters and check them with a multi-meter on the 'ohm' setting.... if it reads "0" then the tweeters are dead. Polk has aftermarket tweeters available for $96 a pair that sound much better than the stock SL-2000 units.

engtaz

Which version of CRS do you have? 1 tweeter or 2 tweeters? Verify which tweeter you have here:
http://www.polkaudio.com/forums/showthread.php?t=25377&highlight=identifying+vintage+tweeters

Do you have the interconnect cable? If so, is you amp common ground?

Take time to answer the questions and then we can give you better direction.

Good Luck and welcome armistad,
engtaz

armistad

The speakers have 2 tweeters in each of them, and they look just like the ones in the picture you linked me to.

I do have the interconnect cable, but I'm not sure what common ground amp means. I have a NAD Stereo Receiver 7155 that the speakers are plugged into.

Let me know if there is anything else I can clarify. Like I said earlier, I don't know much about speakers quite yet, so I really appreciate your help.

engtaz

You have the original CRS's. I am not the expert on these. Try switching speakers wires on the back of your NAD to see if it follows the channel or the speaker.

engtaz

nspindel

I'm pretty sure NAD power will be common ground (SDA's need a common ground amp), I have an NAD 2200 power amp, and it plays my SDA's fine.

Did your father have any problems with these speakers???

engtaz

As long as the interconnect is not plugged in, common ground groud is not a problem.

engtaz

danger boy

it sounds like one or more of the tweeters may be bad.. pull one out at a time.. and hook it up to speaker wires.. at a very low volume on your NAD receiver.. and if it sounds normal for a tweeter. if not.. then it may be bad. do the same for the 6.5" mid bass drivers...

armistad

The speakers haven't been used in the last 2 years, but my dad says they were working great 2 years ago. Is there anything else I should check before I start pulling speakers out of the box? Could this be caused by any faulty wiring or anything of that sort?

engtaz

did you do what I suggested in post #5 swapping speaker wire on NAD?

engtaz

Boywonder

Try swapping the left and right channel speaker wires as mentioned above. That will at least isolate the problem to the speaker(s). DON'T swap the positive/negative leads to each speaker, simply play the right channel thru the left speaker and visa versa, keeping the correct polarity for the wires at each speaker.

F1nut

You probably have a bad polyswitch, which protects the tweeters from clipping damage. There is one on each crossover board. You can get new ones from Polk.

armistad

Hey guys, thanks for all the responses- just a little updated.

I went ahead and switched the channels of the speakers. This didn't help, the left speaker still works fine and the right speaker is still having problems. This means that the problem is speaker specific i guess.

I've been messing around with the balance knob on my receiver and have realized a few weird things though. When I turn the balance knob all the way to the right, only the top tweeter and the top bass driver play on my Right speaker. The bottom tweeter and the bottom bass driver do not play. However, even while the balance knob is turned all the way right, the top tweeter and top bass driver on the Left speaker still plays, but not the bottom tweeter or bass driver.

When I turn the balance knob to the middle, all 4 speakers on the Left speaker play and the still only the top tweeter and top bass driver on the Right speaker play.

When I turn the balance knob all the way to the left. All 4 of the speakers on the Left speaker play, but so do the top tweeter and bass driver on the Right speaker (but not the bottom tweeter or bass driver).

The sound from the system sounds the worst when the balance is turned all the way to the right, it sounds a little better when turned to the middle, and it sounds the best when it is turned all the way left.

Also, it seems as if the problem with my Right speaker is that the bottom tweeter and bass driver are not working, while the top tweeter and bass driver are.

Does this open up any possibilities? Anyone have anything else I should try?

I appreciate all your help

BSUfbfan

As F1nut said, the polyswitch is out which will cause the tweeter to have no output (you can plug the dead tweeter into the other speaker cabinet to verify if it is the tweeter or polyswitch). If you have no sound from a midbass, as I stated earlier, check the impedence of the driver with a multi-meter for a simple way to tell if the voice coil is open.

armistad

Sorry to ask, but I'm not too familiar with working with speakers-

Is it hard to switch the two tweeters on the Right speaker? Is there some kind of guide or CRS layout I can find online that will facilitate me doing this?

Also, where can I get a multi-meter and around how much is it? I'm not sure what impedence is, but is there some other way I can check out what is wrong with the midbass?

Like i said before, the top tweeter and midbass on the Right speaker work and only the bottom tweeter and midbass on the Right speaker are not working. Could this possibly be a problem with the wire maybe?

Thanks again

Ron Temple

Not sure what you're describing. The CRS is meant to be horizontal. The tweeters and drivers are side by side. I'd swap out the non working tweeter and driver with those working on the other speaker. If it sounds right then it's it's the speaker and/or tweeter that need replacement. If the problem still persists then it's probably the crossover or poly.

BSUfbfan

armistad wrote: »

Also, where can I get a multi-meter and around how much is it? I'm not sure what impedence is, but is there some other way I can check out what is wrong with the midbass?

Thanks again

As Ron said, you can swap a non-working driver with one that you know works in the other cabinet, and if the speaker still has no output, it is dead.

You can get a digital mulimeter from Radio Shack that tests impedence (ohm load) for $19. just simply measure across the speakers terminals and if it reads "0" ohms then it goes in the garbage.

amulford

it sounds like the stereo drivers in the right channel aren't working. That could be the drivers, wiring or crossover. If it was only the tweeter, I'd say polyswitches, but not the mid and the tweeter.

BTW, you should turn your speakers 90 degrees to the outsides. The tweeters should be on top, not to the sides.

Libertyc

You have a bad tweeter.

nspindel

Libertyc wrote: »

You have a bad tweeter.

I don't see how you've arrived at such a diagnosis. The guy is saying the tweeter and one woofer are both giving him problems. How do you arrive at the conclusion that the problem is a bad tweeter? Replace the tweeter and the woofer will work???

engtaz

http://www.polkaudio.com/forums/showthread.php?t=55888
You will find the wiring schematics in this thread. You have the 1984 version of the CRS's.
This should help. BSUfbfan stated what you need to look at.

Good Luck,
engtaz

dcmeigs

I have a whole other take on this thing.

Do you understand about the interconnect cable between the two speakers and what it does? One tweeter and one driver in each speaker (the dimensional array) is actually feed from the "other" channel through the interconnect cable. (this is like a 1A in that the tweeter is involved too). If you roll the balance all of the way to the left channel, you will hear the left speakers stereo tweeter and driver and the "dimensional array" tweeter and driver in the other speaker.

I'm wondering if your source IC (wire with RCA plugs) has come loose from the right channel or something along that line. Reconsider your problem in this light to see if anything clicks for you. I understand that my take is not 100% consistant the observations you note, but it is very close.

It could be that one of the wires in the IC is bad too. I like that! Use your new VOM to test the IC. You are looking for discontinuity (a broken wire).