SDA SRS Mods.

drumiv

I'm thinking of starting the process of mod.ing my SRS's. I want to start with stuff I know I can handle. Tweeter replacement seems doable, as does Dynamatting. Also, seems I've read about some sort of metal gasket's to replace originals, although M. Polk recommends rope caulk. My question(s) is this; where to get the stuff. Is there a person in particular at Polk to talk to about ordering such things as tweeters? Any help would be greatly appreciated. I am limited by my low post count, so some access is not there. Thanks

westmassguy

drumiv wrote: »

I'm thinking of starting the process of mod.ing my SRS's. I want to start with stuff I know I can handle. Tweeter replacement seems doable, as does Dynamatting. Also, seems I've read about some sort of metal gasket's to replace originals, although M. Polk recommends rope caulk. My question(s) is this; where to get the stuff. Is there a person in particular at Polk to talk to about ordering such things as tweeters? Any help would be greatly appreciated. I am limited by my low post count, so some access is not there. Thanks

The first thing you'll want to do, is determine which SRS Model you have. If you don't know, post a few photos so we can help you identify them. Once that's determined, you can download the proper schematics for them here: http://www.polkaudio.com/forums/showthread.php?55888-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-Stereo-Dimensional-Array(SDA)
As for easy upgrades, replacement tweeters are available directly from Polk Customer Service. The Telephone # is at the top of the page. Be sure to mention you're a member of Club Polk to receive a discount and free shipping. Be advised that Polk is currently out of stock on both the RDO-194-1, and the RDO-198-1 replacement Tweeters until the end of October.
There are no "Metal" gaskets for the drivers. You may be referring to "Larry's Rings" which install behind the speaker baffle, and provide a more solid way of securing the drivers. Your SRSs should already have threaded inserts for all the front mounting screws, so the rings may or may not be required. The existing gaskets on all your drivers may in fact be just fine. As long as they provide a tight seal, there's no need to replace them. Mortite Rope Caulk would be my absolute last choice for making new gaskets. The preferred material is Armaflex/Armacell foam insulation tape, which you can find just about anywhere. It's 2" wide by 1/8" thick, and must be cut into 3/8" or 1/2" wide strips, depending on whether you're doing drivers, or passive radiators.
Dynamatting the drivers and passive radiators is relatively simple, and while you're at it consider gluing the magnet assemblies to prevent magnet shift. Some use JB Weld or 10 minute Epoxy, but I use and recommend Loctite Power Grab, clear acrylic adhesive. It goes on easy, and cleans up with soap and water. It can also be used to internally reseal the cabinets if needed since it does not contain any silicone.
Further upgrades, such as recapping the crossovers, requires more skill. Several members here, such as Trey/VR3 Mods, and myself, do that type of work.

drumiv

Thanks WMG, that's the type of info I was hoping for. The speakers are the original SDA SRS's based on the owners receipt, which states they were bought in Dec. '85. Am I wrong?

westmassguy

You are correct. There should be four SL2000 Tweeters, six 6.5" woofers, and a 15" passive radiator in each cabinet

drumiv

So I need 8, RDO- 194-1's to start with. I know there're on back order, but I might as well get in line. Is replacing the mids/woofers necessary?

drumminman

westmassguy wrote: »

You are correct. There should be four SL2000 Tweeters, six 6.5" woofers, and a 15" passive radiator in each cabinet

Very good advice from WMG, with most of the important mods listed.

Question: should be 8 midwoofers rather than 6?

westmassguy

drumiv wrote: »

So I need 8, RDO- 194-1's to start with. I know there're on back order, but I might as well get in line. Is replacing the mids/woofers necessary?

That's correct, 8 RDO-194-1s. I would carefully check each woofer by lightly pressing around the perimeter in several spots. There should be no rubbing or odd noises. If the system is functional, by all means fire it up, and check each woofer for sound output, and movement. The Stereo woofers, which are the inner four will be the loudest, followed by the outer four dimensional woofers. The interconnect cable must be installed for sound output from the dimensional woofers.

westmassguy

drumminman wrote: »

Very good advice from WMG, with most of the important mods listed.

Question: should be 8 midwoofers rather than 6?

Correct, Senior moment, and it's early. What's left of my brain cells aren't all firing just yet

markamerica

WestMassGuy,

I am very interested in the prevention of magnet shift on the various and sundry drivers in all my Polk SDAs of various models. Do you know has anybody posted a thread, hopefully with pictures, on this procedure? I've got a lot of drivers to glue, and I'd just as soon do it right. Is the Loctite Power Grab something I can pick up at a home improvement big-box store?

Thanks!

Mark

westmassguy

markamerica wrote: »

WestMassGuy,

I am very interested in the prevention of magnet shift on the various and sundry drivers in all my Polk SDAs of various models. Do you know has anybody posted a thread, hopefully with pictures, on this procedure? I've got a lot of drivers to glue, and I'd just as soon do it right. Is the Loctite Power Grab something I can pick up at a home improvement big-box store?

Thanks!

Mark

Home Depot, Loews, Good Hardware Stores should carry it. It comes in 6oz tubes, which are easier to handle then the caulking gun tubes. Gluing the magnets is not difficult. If you look at the back of the woofer, you'll see a steel back plate (usually with a label on it), the dark grey ceramic magnet, and underneath, the front plate. The magnet is sandwiched between the two plates. You apply a small bead of glue where the plate meets the magnet, on the top and bottom. Then smooth out the Loctite with your finger tip, making sure it fills the little gap completely. What I like about the Loctite, as opposed to epoxy or solvent glue, is clean up with soap and water. Any excess glue on the plates or magnet can be wiped off with a damp rag. Set the woofers aside for a few hours, and the Loctite dries clear with a flat finish. It Looks professional and looks like it's been there since day one. Do not use generic or another brand of clear acrylic adhesive. I choose the Loctite Power Grab specifically because it contain no silicone. Most of the others contain trace amounts of silicone, which you don't want anywhere near a speaker, or the inside of a speaker cabinet. Here's a few photos of what the glued magnets will look like:

markamerica

Thanks WestMassGuy! Loctite Power Grab it will be. The pictures helped, as did your description.

TennMan

How long does Loctite Power Grab take to cure to where the drives can be installed?

westmassguy

TennMan wrote: »

How long does Loctite Power Grab take to cure to where the drives can be installed?

Ronnie, it skins over in 10-15 min, then about a half hour later they can be installed. I always wait for a full cure, 2-4 hours so there's no moisture entrapment inside the speaker cabinet

drumiv

The system is fully functional, WMG, and the the only problem is, now I have a whole bunch of speakers to sell.

TennMan

westmassguy wrote: »

Ronnie, it skins over in 10-15 min, then about a half hour later they can be installed. I always wait for a full cure, 2-4 hours so there's no moisture entrapment inside the speaker cabinet

Thanks David!

westmassguy

drumiv wrote: »

The system is fully functional, WMG, and the the only problem is, now I have a whole bunch of speakers to sell.

Well sell away. You've got a awesome system now to replace them

westmassguy

TennMan wrote: »

Thanks David!

Always welcome Ronnie

oldrocker

Good luck with your project, would lOVE to offer advise cept I'm in the same position as you.
I do know this site has TONS of good advise to get them monsters back to where they should be.....

drumiv wrote: »

I'm thinking of starting the process of mod.ing my SRS's. I want to start with stuff I know I can handle. Tweeter replacement seems doable, as does Dynamatting. Also, seems I've read about some sort of metal gasket's to replace originals, although M. Polk recommends rope caulk. My question(s) is this; where to get the stuff. Is there a person in particular at Polk to talk to about ordering such things as tweeters? Any help would be greatly appreciated. I am limited by my low post count, so some access is not there. Thanks

drumiv

Yes oldrocker, plenty of good people/advice here. These speakers sound frickin' awesome now, I find it hard to believe we can improve them.

drumminman

drumiv wrote: »

Yes oldrocker, plenty of good people/advice here. These speakers sound frickin' awesome now, I find it hard to believe we can improve them.

IF you like them now, you're gonna be blown away when you complete all the mods. :cool:

leftwinger57

While not owning the CRS I do own 87' 2bs. While not the same speaker the mods ,the less expensive ones are easy to accomplish.1.Dynamating easy to find not expensive and very easy to apply and you should hear a difference w/out cabinet resonance and better bass resposne at lower volume levels.2. Either side and or floor deadening material for the same reason,I had some acoustic matting and that's what I used and it works also.3. Tweeters which as we all know by now are not available for a few months.4.Replace any beat gaskets you encounter either w/ gasket tape or Armacell.5.Seal cabinet w/ Liquid Nails type of adhesive for an air tight cabinet. .Then if your into redoing the x-overs knock yourself out. Others here have done internal wiring ,changing binding posts, rings ,gaskets, hurricane nuts and all assorted mods which I have no intention of doing .

westmassguy

drumminman wrote: »

IF you like them now, you're gonna be blown away when you complete all the mods. :cool:

Agreed. If you're handy, and comfortable with a drill and a soldering iron, you can do all the upgrades yourself. They don't need to be done all at once, baby steps are fine too. Some upgrades make a dramatic difference, while others are cumulative.

drumiv

WMG;I am very handy with a drill(all power tools; trim carpenter/cabinet maker), not so much with anything electronic. I have a GREAT tech. though. He'll be doing the XO's. He's doing them on my LS 90's, which I'll now be selling, if anyone's interested. I don't have enough posts to list with you guys(which is a shame, I've got some really nice speakers to get rid of now...darn SRS's!)

westmassguy

drumiv wrote: »

WMG;I am very handy with a drill(all power tools; trim carpenter/cabinet maker), not so much with anything electronic. I have a GREAT tech. though. He'll be doing the XO's. He's doing them on my LS 90's, which I'll now be selling, if anyone's interested. I don't have enough posts to list with you guys(which is a shame, I've got some really nice speakers to get rid of now...darn SRS's!)

Good enough, plenty to be done while the crossovers are out being rebuilt.

Schurkey

westmassguy wrote: »

The Stereo woofers, which are the inner four will be the loudest, followed by the outer four dimensional woofers. The interconnect cable must be installed for sound output from the dimensional woofers.

I don't think that's correct for any but the earliest generation (or two) of SDA speakers.

Below a certain frequency, all the drivers produce bass, even without the SDA cable. Certainly, that's true for my 1Bs, approximately the same generation as the blade/blade SRS.

F1nut

It's kind of splitting hairs....yes, the SDA drivers produce sound below 100Hz when the SDA cable is disconnected, but you're missing a lot.

Schurkey

F1nut wrote: »

It's kind of splitting hairs....yes, the SDA drivers produce sound below 100Hz when the SDA cable is disconnected, but you're missing a lot.

What's missing is the SDA effect on spatial information, but not ordinary frequency response as if those drivers fill a "hole" in the response curve..

The SDA speakers tend to be excellent "ordinary" speakers with the cable disconnected, made even better by connecting the cable so the soundstage widens.

westmassguy

Schurkey wrote: »

What's missing is the SDA effect on spatial information, but not ordinary frequency response as if those drivers fill a "hole" in the response curve..

The SDA speakers tend to be excellent "ordinary" speakers with the cable disconnected, made even better by connecting the cable so the soundstage widens.

I was advising him on a cursory examination. The Dimensional woofers produce sound below 150Hz with or without the Interconnect Cable due to the Dimensional Inductor that was added starting with the 3rd generation. Above 150Hz, any sound coming from the Dimensional woofers with the cable disconnected, is being produced sympathetically due to fluid coupling with the Stereo woofers.