SDA SRS, help, I think I may have a problem?

danger boy

thanks for your post.. often times it's not easy to get information on what amps are common ground to use with SDA's.

Welcome to Club Polk.

chronoman

Hi Meg,I tried sending you message on this forum related to your problem but it's not taking for some reason so here go'es again.
Check to see if your amp is a common ground design or a floating ground design,,,,,,,Polk SDA serie's use to only work correctly with common ground type amp's,it really affect's soundstage and sound color..........I started out in 1986 with a Carver M500t(floating grnd type) and had to trade up to the M1.5t common grnd type to correct the problem........Hope this help's.

amulford

I didn't think of that. It's so ingrained in me (the common ground thing) I forget others may not know...

schwarcw

Thanks for that information chronoman, and welcome to the Club Polk Forums! Sometimes we overlook the obvious.

Carl

meg

Sorry, had to deal with my father this weekend and didn't get to work on my system. Anyway, I would purchase these SL2000. how do I go about that? Do I have any protection in case they don't work?

meg

Yes, I had to make sure that the amp I'm using is common ground. This forum is very helpful.

meg

I will work on my system over the long weekend...

schwarcw

meg wrote:

I will work on my system over the long weekend...

Let us know if you make some progress or discover the problem.

Carl

Tanveer Suleman

Hi Meg,

R u using RCA interconnects from CD to Amp? if yes then swap both the channels and check if problem persists. You can also check some Mono Recording if there is a difference in both the speakers or not. I think your speakers are perfect as you have already swaped them with each other and the speaker marked as right was sounding same like left speaker when it was placed on the left. The problem exists with the source, I'm sure. Let's try some other speakers in your home with this CD player and Amp. I hope the speakers cables of L+R are of same length.

meg

So far, I tested each tweeter and each has sound. I disconnected each one and I also connected the amp to the high frequency posts, and there was sound on each also. I also tested in mono, and there was sound. Can a tweeter be bad and still output sound? Its clear that the left channel high frequencies are louder than the right channel. Should the tweeters on each channel output about the same corresponding sound volume? In other words, should the first tweeter on the top of each speaker output about the same level and the second tweeter and so on...? If I stand in front of each, its clear the the left channel outputs louder high frequencies than the right channel. In other words, I can clearly hear the sound of the symbols and snare drums on the left channel and barley hear them on the right. Sometimes I hear the voices on the left channel substantially louder than the right. It seems that the left channel takes the priority over most of the highs. The right channel does put out the highs but less than the left. Now, am I crazy or could this actually be the design of these speakers that I have never heard before? I have a pair of SDA-1 and I have placed them side by side with these. On the SDA-1, they only have 2 tweeters in each speaker so its clear that each matches on left and right stereo and dimensional. The highs are the same on each channel. Could this actually be a crossover issue? I have another amp coming soon that I was planning on running these speakers in bi-amp mode, could this help? It's possible that the the only way for me to solves this issue to to be able to hear another pair. This hurts!

amulford

So far, I tested each tweeter and each has sound. I disconnected each one and I also connected the amp to the high frequency posts, and there was sound on each also. I also tested in mono, and there was sound. Can a tweeter be bad and still output sound?

Ok. You have determine each tweeter is outputting (sp?) sound. Normally if they are bad, you won't get anything.

Its clear that the left channel high frequencies are louder than the right channel. Should the tweeters on each channel output about the same corresponding sound volume?

That would depend on the recording. But since you went mono, they both should have about the same output levels.

Should the tweeters on each channel output about the same corresponding sound volume? In other words, should the first tweeter on the top of each speaker output about the same level and the second tweeter and so on...?

No, IIRC, the tweeters are cascaded according to frequency and/or power. The crossover is a complicated iso phase (whatever the hell that means) network. They are somewhat independant, so outputs can vary in each tweeter in each channel.

Sometimes I hear the voices on the left channel substantially louder than the right. It seems that the left channel takes the priority over most of the highs. The right channel does put out the highs but less than the left. Now, am I crazy or could this actually be the design of these speakers that I have never heard before? I have a pair of SDA-1 and I have placed them side by side with these. On the SDA-1, they only have 2 tweeters in each speaker so its clear that each matches on left and right stereo and dimensional. The highs are the same on each channel. Could this actually be a crossover issue?

It is really starting to sound like one. Or a problem with the amp. When you used the SDA - 1's, did you use the same amp to drive them that you were using for the SRS's? In other words did you diconnect the SRS and plug the SDA-1 with the same wire? Voices are mostly mid frequency range, so the amp may have a weak channel. What amp is it?

I have another amp coming soon that I was planning on running these speakers in bi-amp mode, could this help?

This isn't going to help this problem, but will help when we get this fixed. It might help diagnosing this problem. Try it when you get it in place of the amp you have in there now.

It's possible that the the only way for me to solves this issue to to be able to hear another pair. This hurts!

Nah, you don't have to get another set. If you are having a problem with a crossover, don't worry. We can get that fixed right up , too. Just hang in there man. I had a set of speakers torn apart for over a year, I just finally got them back together a little while ago. I feel the pain.

schwarcw

meg, Since you swapped the input wires from the amp and the problem stayed with the same speaker, I don't think it's an amp.

What I would suggest is swapping crossovers from one speaker to another. It's pretty easy since all the inputs and outputs to the crossover use wiring harnesses and plugs. This will tell you if the problem is in the crossover.

Carl

amulford

I may have missed it, but when did he switch over the inputs?

schwarcw

Anthony, check out his quote. I would suggest that he switch crossovers. If he's elimated the amp and the tweeters as the problem. it may be something in the crossover. I don't know what else he can try.

meg wrote:

Thanks for your help... I switched the output from the amp and the issue stayed with the speaker, so I eliminated the amp as the problem.

amulford

OK. Yep, we're down to the crossover. Try switching them like Carl says.

Now there are a couple of thing to look at on it. Take a close look at the connections. Try to wiggle them and take them apart, then put them back. The fit should be snug, and if you do this a couple times, it will clean 'em a little. If this does something, I'd suggest you get some Caig DeOxit and Pro Gold to clean all of them.

If it didn't do anything, it may be a crossover component, and for that I would suggest you talk to Ken Swauger. He may be able to tell you exactly what to check out on the crossover, or you can make arrangements for them to take it, troubleshoot and fix it.

It may be the polyswitches, and there is a way to check that. If you jump them, and it comes to life, you'll know. If not, I'd suggest you turn it over to Polk.

Any body have a picture of crossover to show him what he should look for?

schwarcw

Hi meg

The attached photo is of a pair of crossover. The one on the left should look similiar to yours. On the middle, lower edge of the board, look for the red, female 4 plug connector. Just behind that connector is a small, round mustard colored piece about 3/8" in diameter. That is the polyswitch. This MIGHT be the problem. If you can jump it with a wire connected to two alligator clips give it a try.



Carl

amulford

I like the job on the upgrade. Nice

whitetruk

amulford wrote:

I like the job on the upgrade. Nice

awesome,man i gotto do that

meg

Wow! Question; is the crossover you are referring to the black panel on the front of the speaker or in the rear where the interconnect cable is? Is this something you think I can actually do if I have never done it before? I do think swapping the crossovers will eliminate another variable.

amulford

Take off the front grills and then remove the passive radiator. You can't miss them. Just be sure to write down the wiring, so you can hook it back up right.

schwarcw

meg wrote:

Question; is the crossover you are referring to the black panel on the front of the speaker?

Yes! The crossover pic that I posted will be somewhat different from your's since you have a later model SRS.

Give the crossover swap a try, it's not that difficult. A screwdriver is probably all you need. Maybe an Allen wrench.

Carl

F1nut

Meg,

On your speakers the crossover is mounted to the backside of the large black panel on the front. You do not have to remove the PR.

The wires are soldered to the crossover boards, so be sure you make a drawing first and get a second set of hands to help hold the crossover assy's.

amulford

Thank you Jesse, I wasn't aware that panel came off.

F1nut

Eh, that's what bro's are for.

dudeinaroom

welcome to the forum meg. Have you tried different cd/records/tapes. And if you are like me and cannot get an equal distance from outside walls you could hang a decorative blanket on the wall next to the one that is closer to the wall.

jcmccorm

Maybe I could back up a bit and ask what kind of receiver or preamp is being used to drive these?

The balance control has already been covered. If this is even a somewhat modern receiver or preamp, there will be individual level settings for each speaker that should be checked to see that they are equal.

Apologies if the audio source (receiver, amp, preamp, etc.) has been eliminated as a problem, but I hadn't read that it has yet.

Cary

rocketman

Use a paper towel roll to put up to each driver,it works great to tell if the driver is workiing.

meg

Hi all, sorry I have been killed with the holidays and business travel. You have all been very helpful...

My preamp is a McIntosh C15 and I have one Monster MPA2250 amp with another Monster MPA2250 Amp coming next week. I haven't tried swapping the physical speakers themselves. Maybe the acoustics or my ears may be an issue. I really don't think so since I can stand directly in front of each speaker and hear the difference. Its frustrating when I listen to good music and I hear the percussion highs dominated on the left speaker, unless thats what Mathew Polk intended with these??? I never heard that with my SDA1's but then again, these speakers have a lot more inside...

F1nut

Meg, I think at this point you should contact Polk and talk to some of the techs about the issue. Please let us know what they say.

meg

Hi all, sorry its been so long. I took it upon myself to disconnect every speaker and crossover and reconnect. Speakers sound fantastic! I don't know what the problem was, but disconnect and reconnect seemed to solve it. I just wanted to thank you all for all your assistance. Without you, I would not have solved this problem. Thanks again...
meg.