polk SDA 2 B cross-over upgrade

pitdogg2

Hello out there,
I am new here just bought my first pair of SDA's. They are SDA 2 B they have 2 6.5' woofers,1 12" passive radator and 1 tweeter in each speaker.
I am handy with the soidering iron have a buddy that builds his own speakers.
So my question is all you upgrade aholics out there what would be my best option and where do i order the parts from please include part numbers and such so i get the very products you are describing. Maybe give me a little up front knowledge on the pitfalls I only want to do this one time and perfect so i can now move up from my Cerwin Vegas D7's that are 25 years old.
Thanks for the help in advance
Pitdogg2

F1nut

Welcome to Club Polk.

http://www.polkaudio.com/forums/search.php?searchid=11646351

Face

I never saw your write up Jesse, nice job.

Here's one more to add to the list: http://www.polkaudio.com/forums/showthread.php?t=87121

nspindel

Hey, don't forget about mine. Have since sold these to Big Dawg. He's a happy camper.

http://www.polkaudio.com/forums/showthread.php?t=62106

F1nut

Thanks Mike. To be honest, I'd forgotten all about until I saw it come up in the search.

pitdogg2

WOW that is a LOT to absorb I thank all that posted. I really didn't know I was in for 600.00+ dollars to do this upgrade. So I guess it's my karma for buying(stealing) these speakers for 50.00 from a little old lady with a walker that got stuck with them when her son left for college 20 yrs ago and never came back. So to be sure we are all talking apples to apples. Mine look like Nspindels but have a vinyl veneer and are not wood laminate(later version maybe) so might that change anything? My numbers as follows Right speaker SDA II 13989ser# left speaker SDA II 13991ser# each has the following 1xMW6503 Mid L.F.(stereo) 1xMW6511 Mid L.F. (Dimensional) 1x SL2000 H/F 1xSW121 Passive. So while reading I read the connecting cable up grade SO am i mistaking in reading that i can upgrade that to a 5way binding post and can run both the wires(inside) to one binding post? I'm confused...mind you I have not opened these up and have not even brought them home to my house yet (going through divorce) as I don't want them to get caught in that drama as all other gear has. It's just a good thing my Carver TFM45 and Carver C16pre-amp and Sony ES X33 CD player were pre-marriage and I can't wait to hear them through that stuff:) I also ran my Cerwin D7's as a sub-sat type of set-up i have built old JBL cabinets with 15" Eminence woofers with sedgehammer X-over's that roll to the D7's @90hz under each D7 speaker set-up as 8ohm knowing that the SDA's are 6ohm I would like to still use the subs the same as i do now any comments on ant problems I will run into? Sure as heck don't want to blow up the amp that was just rebuilt 2yrs ago by Roland @ carver service.

F1nut

So to be sure we are all talking apples to apples.

If yours have the pin/blade IC, then yes.

run both the wires(inside) to one binding post?

You cannot do that.

inspiredsports

Welcome to Club Polk pitdogg2,

If I were doing it, I would get settled and first hook them up without worrying about the external subs.

First, determine if you have Blade/Blade or Pin/Blade female connections for the Interconnet cable on the back of the speakers. If Pin/Blade, you will have to build yourself or buy aftermarket as Polk no longer makes them. Polk still had a few Blade/Blade last year, and they can frequently be found used for around $40 on eBay. HOWEVER, stock quality was just OK. Best to use quality 12 gauge silver wire and make them yourself.

After properly interconnected and cabled to your amp, you should experiment with positioning. The SDA 2B's will pound out a tremendous amount of bass when properly spaced from the rear wall. Distance from sidewalls, distance between left and right speaker, keeping plane of speakers parallel to rear wall, and listening position will determine your ability to create an SDA "sweet spot".

After you get to know the speakers a bit, tackle the crossover upgrade so then you can truly appreciate the improvement. The BE1807-B "TL" crossover rebuild is fairly straightforward and $600 is about right with new Cardas binding posts, new RDO-198 tweeters, and caps and resistors from soniccraft.com. You could also go crazy with Mundorfs and really wreck the budget, but Sonicaps are a tried and true favorite around here.

After about 400 hours of burn in, you will have a pair of some of the best sounding speakers ever built.




You can continue your "drink from a fire hose" about SDA 2B's at . . .
http://www.polkaudio.com/forums/showthread.php?t=74945

pitdogg2

Nope mine would be the blade/Blade type and it sure looks like a cheesy little cable. I do subscribe to the Tim the toolman mentality bigger is better so yes i was a little disappointed when she (little old lady) brought out the cable. I was thinking that Polk was doing a switch somehow where the little blade on one end wire went to the larger blade on the other end but nope i seem to be wrong there when testing with an ohm meter

inspiredsports

The stock cable will actually do the job, but 12 gauge silver really opened mine up. There's a guy on eBay who goes by navships who has great prices, quality and service. You can generally buy the better wire and plug ends for about the same amount or money you can resell the stock blade/blade cable for, and you will come out ahead in sound quality.

Only the small blade carries signal on the SDA 2B, the large blade is connected to absolutely inside of the cabinet.

You can find the schematics for both SDA 2B pin/blade and blade/blade in Post #3 at http://www.polkaudio.com/forums/showthread.php?t=55888s

F1nut

My take on silver wire. If you need to open the top end, then it might be for you, but many find silver wire on the bright side. Also, sliver cable doesn't carry the low end as well as copper wire.

pitdogg2

Well I wasn't really looking for silver but more of a 12-10ga replacement with a better hook up mine seems to be a little loose. there is not much grip when the blades are inserted. When i seen the one thread where the guy made his out of high end Monster and spades to a better binding post i thought that would be something i could do. I also have access to a lot of cat 6 wire any thought on that ? Several friends of mine braid 3lengths of that and either terminate to spades,bananas or just bare and swear it makes great speaker cable.

inspiredsports

F1nut wrote: »

My take on silver wire. If you need to open the top end, then it might be for you, but many find silver wire on the bright side. Also, sliver cable doesn't carry the low end as well as copper wire.

Hmm . . . I never really considered that as I (maybe mistakenly) thought the SDA circuit on the 2B's was limited to to the frequency response range of just the 6.5" MW6511 and not the tweeter.

My handmade 12 gauge 9 strand silver replacement wire seemed (to my ears) to open up the mid and bass versus the stock cable.

I made the same cable for my SDA SRS II's and feel the same way about the improvement there too.

fbm211

I also made a DIY interconnect cable.I used a 8/ft run of DH Labs T-14 speaker cable and terminated it with cardas silver spades.Much better SQ than the stock cable.
Dont forget to mortite those SDA drivers Pitdogg2.

pitdogg2

fbm211 wrote: »

I also made a DIY interconnect cable.I used a 8/ft run of DH Labs T-14 speaker cable and terminated it with cardas silver spades.Much better SQ than the stock cable.
Dont forget to mortite those SDA drivers Pitdogg2.

so when you made your cable you just took your binding post's and made say the red the large blade and the black binding post your narrow blade and then attached one wire inside to each? then you would of course like any other speaker +(red) -(black) would be the way you attached the IC cable. Why (mortite) is it that much better than other speaker gasket sealing material you'd get from parts express or madisound?

comfortablycurt

pitdogg2 wrote: »

Why (mortite) is it that much better than other speaker gasket sealing material you'd get from parts express or madisound?

People have experimented with several alternative gasket materials, and the consensus is that Mortite is the best. Not to say that other materials won't work, but considering it's relatively low cost, it's worth it to spring for the Mortite.

I actually just got some Mortite and Dynamat Xtreme for both my SDA 2A's and my Monitor 7A's. I haven't applied it all yet...waiting for a rainy weekend or something like that.

fbm211

pitdogg2 wrote: »

so when you made your cable you just took your binding post's and made say the red the large blade and the black binding post your narrow blade and then attached one wire inside to each? then you would of course like any other speaker +(red) -(black) would be the way you attached the IC cable. Why (mortite) is it that much better than other speaker gasket sealing material you'd get from parts express or madisound?

I replaced the b/b connector with 1 binding post in each terminal cup.The large blade does not serve any signal purpose as it is not in the signal path.+(red) -(black) does not matter in this case...I soldered both 14g leads to the spades to make the cable 11g....

ben62670

F1nut wrote: »

My take on silver wire. If you need to open the top end, then it might be for you, but many find silver wire on the bright side. Also, sliver cable doesn't carry the low end as well as copper wire.

I agree with your statements in general when it comes to silver speaker wire. Silver plated copper works great for SDA IC's for the reasons you mention. The lack of low end bass with the silver SDA wire helps prevent as much lower frequency cancellation in the dimensional arrays. The mid range with stock, or half assed cables sound muddy in the dimension arrays. Silver plated wire can be had cheap on ebay. Use at least 16ga, and I wouldn't go higher than 12ga.

inspiredsports

I think that's what I was trying to say too.

Am I right that the highs can't be opened up with a silver plated SDA interconnect cable wire as the high signal is not sent from the crossover network to be reproduced only by the 6.5" SDA drivers?

The argument might be that it "supresses" lows in this use, but I don't think it can affect the highs when used in the 2B's SDA circuit.

The suppression of lows would also not be a bad thing as I believe the SDA effect was always meant to be limited to the midrange ???

pitdogg2

All have been really helpful and have opened my eye's to theese fabulous speakers. Two more questions I can think of are do the rubber surrounds on the 6.5's or the passive ever need replaced like on other speakers? What are the rated W.P.C. these polk SDA2B's rated at? As i mentioned in a earlier post the TFM can really pound out the watts in excess of 350 so I like it loud and some have mentioned a cut off for the tweeter so i don't want to fry anything on these so any info would be great
Thanks
Ivan

NJPOLKER

I don't believe you'll have any problem ever with the surrounds unless you or someone screws them up. Good clean power is the most important thing to be considered when looking at power to supply your speakers. Of course it should be common ground which the TFM is. The poly switches will cut the signal to the tweeters when you clip/distort the SQ.

inspiredsports

The original literature that came with mine in 1987 shows 10-500 watts/channel (the low 10wpc boasting of the speakers high 92db efficiency rating) and a maximum output level of 120 db.

With a clean power source they will allow you to blow your eardrums out, with the drivers still sounding nice and sweet.

F1nut

the SDA circuit on the 2B's was limited to to the frequency response range of just the 6.5" MW6511 and not the tweeter.

Good point.

inspiredsports

F1nut wrote: »

Good point.

Thanks!

superjunior

tsnany115 wrote: »

wonderful! thanks for the info..

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pitdogg2

comfortablycurt wrote: »

People have experimented with several alternative gasket materials, and the consensus is that Mortite is the best. Not to say that other materials won't work, but considering it's relatively low cost, it's worth it to spring for the Mortite.

I actually just got some Mortite and Dynamat Xtreme for both my SDA 2A's and my Monitor 7A's. I haven't applied it all yet...waiting for a rainy weekend or something like that.

Dynamat Xtreme ? using that to stick to the inside of the cabinet like the car audio people do to their trunks? Are you applying to all sides? Does that increase perceived bass response? Do you put the Mortite just where MP put the original gasket seal or are you putting under the speaker flanges?

Face

You would apply it to the back of the basket to dampen it and prevent it from ringing.

inspiredsports

post #25 shows my "WAY OVERKILL" approach on my passives . . .

http://www.polkaudio.com/forums/showthread.php?t=74946

The 6.5 mids should be done also, but YOU REALLY NEED JUST A COUPLE OF SQUARE INCHES on the back of each "spoke" of the basket. Your tweeters do not need Dynamat.

When removed, carefully hold a driver and "flick" one of the spokes on a driver. You will hear a "ring" or natural resonance of the metal used. Damping that ring out with Dynamat Extreme keeps the driver from interjecting that resonance into your music.

pitdogg2

inspiredsports wrote: »

post #25 shows my "WAY OVERKILL" approach on my passives . . .

http://www.polkaudio.com/forums/showthread.php?t=74946

The 6.5 mids should be done also, but YOU REALLY NEED JUST A COUPLE OF SQUARE INCHES on the back of each "spoke" of the basket. Your tweeters do not need Dynamat.

When removed, carefully hold a driver and "flick" one of the spokes on a driver. You will hear a "ring" or natural resonance of the metal used. Damping that ring out with Dynamat Extreme keeps the driver from interjecting that resonance into your music.

WOW you guy's must have better hearing that Bat's:)
but really it's right up there with if it ain't helping it sure ain't hurting I will put it on the list also. I did hear that clanging sound from the passive when i loaded them and thought to myself that something was sure loose inside thought the crossover came apart until i played them at a buddies funny thing he offered 350.00 on the spot i smiled and told he could come to my house and visit them anytime day or night.;)