CRS+ Troubleshooting SDA issues

jimbo1421

Hello everyone,

For the past two weeks since going over all the internal wiring (see http://www.polkaudio.com/forums/showthread.php?128798-CRS-crossover-miswired) I have been listening to these CRS+ and giving them some break-in time after their long storage. I have them set up as shown in the attachments except that the CRS+ replace the SDA-1b in the photos. The CRS+ are set on a pair of Monitor 10 boxes. I have had a chance to compare these two SDA models using "Take Five" by the Dave Brubeck Quartet as a reference. Both pairs have had the Dynamat and Mortite treatment, but no upgrades or modifications to the crossovers. The SDA-1b have the original SL-2000 tweeters; The CRS+ have the RDO-194 tweeters. The CRS+ have 5'-9" between them (inside to inside) and the listening spot 7'-9" from the plane of the soundboard. The right speaker is 1-1/2" in front of that short dividing wall which places the back of the speaker 23" away from the back wall. I hope that eliminates the need for 36" side wall clearance on the right.

Both sets of SDA speakers have passed the tests in the user manuals and the Quick Test of SDA Functions PDF.

As expected, the CRS+ with the RDO-194 tweeters are easier on the ears than the SDA-1b, but I also find a greater degree of detail from the CRS+. Bass response is crisper and more musical than SDA-1b although the SDA-1b reaches deeper. Perhaps, as I had hoped, the rear facing passive bass radiator functions better at the 23" distance from the back wall.

I find that the CRS+ soundstage does not extend more than a foot beyond the outsides of the speakers, whereas the soundstage of the SDA-1b extends as much as 4' to the left and 7' to the right. From the SDA-1b, on "Take Five" Paul Desmond's sax appears in front of the fireplace while Brubeck on piano appears in the direction of the display cabinet. The drums originate from the left speaker and string bass around left center. From the CRS+ the sax moves inward to just in front of the drums on the left speaker, while the piano appears just to the right of the right speaker. In brief, the soundstage is broader and the imaging is much better with the SDA-1b. My expectations are for the soundstage to extend well past the space occupied by the speakers and thus give more space between individual instruments.

With the CRS+ I tried disconnecting the IC. The soundstage was reduced to within the space of the speakers and became shallower as well. In other words, they behaved as ordinary stereo speakers.

Due to its greater detail and more musical bass response I would really like the CRS+ to be the keepers here and sell the SDA-1b pair to pay for the TL upgrade. What can I do to improve the soundstage of the CRS+?

Regards,
Jim

LR audio plan 6a.pdf

thsmith

The right speaker being right next a wall is hurting you in both situations. You need at 30-32" between speaker and wall.

thsmith

Try pulling both speakers forward 3-5" so you have at least 3-4" past the side wall. In either case looks like you do not have an ideal location in current location.

jimbo1421

thsmith wrote: »

Try pulling both speakers forward 3-5" so you have at least 3-4" past the side wall. In either case looks like you do not have an ideal location in current location.

Thanks for your comment, thsmith. I just tried this and the width of the CRS+ soundstage actually decreased a bit. Remember, the SDA-1b had a soundstage 6' wider on the right and 4' wider on the left.

Could I still be having electronics issues in spite of passing all the tests? Another odd phenomenon I have noticed is that sometimes a TV show or DVD with a stereo sound track will come out sounding real surround-y for brief intervals. Could old caps and resistors cause some slightly misaligned signal phases?

Jim

thsmith

Certainly could be you need to upgrade the xover. Double check your internal wire including drivers

gimpod

Jim, Not to be an insensitive **** (but I am one ) here it go's.

Your biggest problem is that room (it sucks for SDA's) and setup, SDA's REQUIRE at least 36" of clearance to the side walls and should be no more than 6" - 8" from the back wall (the further away from the back wall the less bass response) and at least 6' apart. At this point your only options are to move or if you can remodel i.e. get rid of the fire place and remove those windows so you can move everything down that wall. Also spiking those SDA's and getting a proper set of spiked stands for the CRS+'s will help a lot too.

Now Caps and resistors could be giving some problems but not as much as you current set up is. The internal wiring on those CRS+'s, I believe we got you straitened out on that.

Warned ya I was an insensitive ****. :cheesygrin:

jimbo1421

Hi, gimpod,

Do SDAs absolutely require 36" clearance from a side wall even if the sound board is 2"-5" in front of the end of that short wall? Actually, that is an opening 7'-10" wide x 6'-8" high. I had hoped that this placement would give me plenty of clearance by adding in the length of the dining room on the right. Is the SDA effect affected by stuff behind and to the side of the speakers? Like the fireplace, window trim, sashes and blinds? Must I have 15' of smooth, flat wall space to make this work properly?

Jim

gimpod

Now this is just my opinion and others may disagree. It's been my experience that anything next to the outside of the speaker affects the sound even if it's behind the plain of the front baffle of the speaker (Bookcase, CD rack etc..). Yes a good 15' - 20' of smooth, flat wall space to start with makes for a good canvas, you can add sound treatments, pics etc... and see how it affects the sound as you go along. But proper setup of SDA's is essential for them to preform there best. Now I realize not everyone can design and build there home around a pair of speakers so most of us make the best of what we have with me I found that my bed room was better suited to my SDA's than my living room so I swapped them. My bed room is now my living room and my living room is now my bed room of course it helps that I'm a confirmed bachelor so there's no WAF to deal with or care about.

jimbo1421

Thanks for your comments, gimpod. It sounds like I need a real estate agent to solve this problem.

What puzzles me is why do the SDA-1Bs have so much broader a sound stage than the CRS+.

Jim

thsmith

Do you have a room in your house that would be more ideal to setup just to test and see what results you get?

It may tell you more about if you have a problem or not.

jimbo1421

thsmith wrote: »

Do you have a room in your house that would be more ideal to setup just to test and see what results you get?

It may tell you more about if you have a problem or not.

I have one other wall in the bedroom which is 13'-8" with a door in one end. I would have about 4'-4" between the speakers. It will be awhile before I could set that up.

Jim

gimpod

jimbo1421 wrote: »

Thanks for your comments, gimpod. It sounds like I need a real estate agent to solve this problem.

What puzzles me is why do the SDA-1Bs have so much broader a sound stage than the CRS+.

Jim

Yea SDA's can be a real PITA to get setup right, but once you do there a great speaker. That fireplace really screws you up to bad they couldn't have put it on the short wall. On the CRS+ it could be because you've got them sitting on empty box's, you really need a proper set of stands for those that will get them 26"-27" off the floor.

jimbo1421 wrote: »

I have one other wall in the bedroom which is 13'-8" with a door in one end. I would have about 4'-4" between the speakers. It will be awhile before I could set that up.

Jim

All though not ideal this would be better than where you have them now and would give you a better idea of how these speakers can really preform at least for testing everything out.

Let me leave you with this thought "SDA's are a lot like democracy, You've got to want them/it really bad and put up with a lot of BS setting things up right in order for them/it to work right."

jimbo1421

OK, then. The next item will be speaker stands. I had always thought that tweeters should be at about ear level. That would be 40" off the floor and the stand therefore would be 30-1/2" high. However the steel tube stands that Polk used to build are 26-1/2". Why are they 4" shorter?

Jim

jimbo1421

Just an update to this old thread. Over the last 2-1/2 weeks since my last post these CRS+ have been gradually improving. Also, I discovered that one of the IC cables from my preamp had worked loose about half way out of the socket. fixing that helped a good bit. But ever since the SDA effect has also been improving, until this evening, listening to Roxy Music Avalon several of the cuts were wrapping around to both sides of me. These CRS+ had been stored for an unknown period and the seller did not even have the IC so the dimensional drivers have been unused for a very long time. I think now they are finally broken in. Would the dry climate here in New Mexico cause the drivers to stiffen up so that they could pass the Quick Tests, but still not really coordinate well with each other?

Regardless of why they have improved, they are now officially keepers. I look forward, down the road, to recapping and doing the TL upgrade. So, to all who helped me here, thank you.

Jim

PS: Can anyone answer my previous post about the proper height for CRS+ stands?

F1nut

I'm glad you are now enjoying your CRS+'s in all their glory.

Can anyone answer my previous post about the proper height for CRS+ stands?

I'd venture to say that Polk felt 36" was good enough.

PolkClyde

I have a bad setup for my BIG Polks.... I need a bigger house/Room ..... Question, does polk have a CD to test to see if my SDA is set up right or close to being right?... I could call Polk, I know. Or what would be a good Test CD for the SDA effect... I know there's a list of CD'S here on the forum. what do you think is best CD for that?, F1NUT and Guys. Thanks.... you guys are the greatest.My SDA effect is not that bad... it's just I hear more of that SDA sound on my right speaker. I did notice an Improvement when I more the left speaker a Little... it's real tricky.

headrott

Not sure what CD's you own, but one of the best I've heard for SDA is Jon Anderson's "Toltec" CD as I put on the list. Madonna's "Ray of Light" CD is very good as well or her song "Rain". Roxy Music's "Avalon" CD is good. Or Depeche Mode's "Violator" as well. Any of these would be a good test. Particularly the Jon Anderson or Madonna CD's.

Another key factor in getting the best SDA sound is making sure your speakers are not toed in or out AT ALL and that they are 100% leveled. I hope this helps you out.

Greg