SDA-less

Mr. Bubbles

I finally got the new (to me) SRS's hooked up and the sound quality is great. Detailed with a lot of bass extension and depth but no obvious SDA effect, and everything seems shifted to the left. Vocals just inside the left speaker and electric guitars and violins right where the left speaker is at instead of far out left like with the 2B's and 1C's. Sounds more like a normal stereo set with almost no 3D effect. All drivers are working. Too late tonight. Guess I check it out more tomorrow. If any of you guys have run into this and have any pointers on what to check first it would be greatly appreciated.

dcmartinpc

Get the SDA schematics to double check all the wiring. Double check polarity and that each driver is functioning. The only was I have done this in the past it to pull each driver and play music while the driver is out of the cabinet to see if it moves.

Have tou tried a different SDA interconnect to verify it is not faulty?

My guess is that it is a wiring problem.

Don

drumminman

When I first got my 2.3TL's, I felt like the imaging was not what I was hoping for. When I opened 'em up I discovered some of the wiring was not stock, and had not been done all that well, especially the IC connection.

Once I corrected that, and made a new IC cable, the imaging was much better.

Pull the passive and have a look. Could be something as simple as loose connections. After all, these speakers are 20+ years old. They'll probably need a little TLC

Mr. Bubbles

GOT IT ! Oxidized connection in the right channel interconnect. Still some work to do; they still don't image like my 2B's but still sound awesome, I'll have to see what can be done with no money for now ( I just spent it all on the purchase). I'm sure a good going through and checking all connections and cleaning will do wonders. Seals as well. man I couldn't believe how crappy the x-overs seals are. The ones on these couldn't have been too good from day one, I suspect. Cabinet is routed and the seal is layed in the routed area, not so bad, BUT; the threaded inserts are not all flush with the baffle; some are flush with the routed surface, some are level with the front of the baffle and one even protrudes about 1/16" farther than the baffle. BUT, given the crappy seals and oxidized connections , they still sound pretty good. Can't wait to hear them after a little TLC.

quadzilla

If that's the case, your next step should probably be to pull all the drivers and check those connections as well.

OldmanSRS

My SRS1.2's had the input terminals mis-marked and reversed +/-. I used them for years with no SDA effect until one day I accidently reversed the +/- and WOW. Always thought they sounded a little narrow and never realized what I was missing. Years later I read about that snafu here.

Maybe not even relevant but verify yours if you get a monent.

stubby

Cheap and easy hop-up - remove original polyswitches (tweeter protection) and replace with new ones. Or, just add a jumper OR install a .5 ohm resistor. Those little buggers can cause all kinds of sonic anomalies.

drumminman

You're gonna have fun learning about these.

I gotta warn you - once you get inside those speakers the mod bug is gonna bite - HARD! :biggrin:

There are several tweaks you can do that don't cost alot of money. One of the best ones is to replace the IC socket with a quality binding post (such as Cardas), and a new heavy gauge IC wire (12 awg speaker will work just fine) with spade connectors. The difference will probably be fairly dramatic.

If you haven't already done so, search for DarqueKnight's posts on the mods he did to his. You'll get lots of ideas :cool:

Have fun!

quadzilla

stubby wrote: »

Cheap and easy hop-up - remove original polyswitches (tweeter protection) and replace with new ones. Or, just add a jumper OR install a .5 ohm resistor. Those little buggers can cause all kinds of sonic anomalies.

Ack, no. .5 Ohm is too much resitor from my experience. .1-.2 is more like it. When I replaced my polyswitches with .5 Ohm the speaker sounded very, very veiled. The polys measured .2 Ohm, which would explain why .5 sounded like ****.

If you do decide to replace the polyswitches, measure their resistence and replace with the same value resistor. Or just leave them out. Some people prefer that sound. Or, if by chance yours do measure .5 Ohm, then yeah, go with that value.

Mr. Bubbles

Will start by removing all drivers and checking / cleaning connections, removing poly switches as previous owner described them as cutting out some. I will check all wiring as per the schematics and diagrams in the sticky. I think the interconnect will get changed since it has already been found to be oxidized. While I'm in there I'll check all capacitors and resistors for tolerance( I know they should be updated, but cost currently will prohibit that). I will also check to see if I have the materials around to make some rings and spikes and will reseal all drivers and crossovers. I also have to replace the grille cloth, IMMEDIATELY, "if those things are going to stay in the living room". (words from the boss). I've got to keep it simple and cheap for now.

I see the Mye spikes are pretty highly recommended here. I can pretty much make any type of spikes but am curious how much difference there is between the conicle spikes and the ones that look like sharp tipped threaded rod and nuts (sound wise). can anyone that has had experience with this please let me know. Naturally it will be much easier to make the latter, but I don't want to take a shortcut and cut myself short. I do not have any brass stock so to make the conicle type, I would be using aluminum or steel. I could even do an aluminum with a threaded tip similar to the latter spike I described earlier, (for easier adjustment). I think I've seen some like that somewhere.

nooshinjohn

While you have those drivers out, get yourself some Armacell and replace the stock gaskets with this stuff. Armacell is a soft, adheisive backed insulation tape you can find at home depot. This stuff is far better at sealing the drivers to the cabinet than the old gaskets and is a very cheap mod to perform while the drivers are out.

audiocr381ve

quadzilla wrote: »

Ack, no. .5 Ohm is too much resitor from my experience. .1-.2 is more like it. When I replaced my polyswitches with .5 Ohm the speaker sounded very, very veiled. The polys measured .2 Ohm, which would explain why .5 sounded like ****.

If you do decide to replace the polyswitches, measure their resistence and replace with the same value resistor. Or just leave them out. Some people prefer that sound. Or, if by chance yours do measure .5 Ohm, then yeah, go with that value.

Is this true for the SDA-2B TL's? I think I have some .5's for my poly's. I might want to experiment

Mr. Bubbles

While you have those drivers out, get yourself some Armacell and replace the stock gaskets with this stuff. Armacell is a soft, adheisive backed insulation tape you can find at home depot. This stuff is far better at sealing the drivers to the cabinet than the old gaskets and is a very cheap mod to perform while the drivers are out.

Thanks for the input. Already planning on heading to Lowe's shortly for some insulation tape. Had read about the Armacell, didn't realize it was that easy to find.

Got all drivers pulled and seals look terrible. Soldered all terminals to the wiring. Some took good and some did not. Going to clean all terminals on the drivers as well. The clear tweeter wiring looks ok on the ends but appears to have some internal oxidation. looks like I'll be rewiring the cabinets when financing allows. I'll rework the x-overs at the same time.

nooshinjohn

oliverbubbles wrote: »

Thanks for the input. Already planning on heading to Lowe's shortly for some insulation tape. Had read about the Armacell, didn't realize it was that easy to find.

You won't find armacell at Lowe's. Home Depot is the only place I know that has it on the shelf.

Mr. Bubbles

Not a Home Depot near me. I got what is probably close; high density foam weatherstrip. Either way it has got to be better than what was on there. I'll investigate the Armacell and see what the difference is. If need be I'll change it out later, when I rewire.

I can see that the top and Bottom are bolted on. Can anyone tell me how the side peices come off? They appear to be snapped in the middle but I can't tell if they are attached to the top and bottom plates or just the sides.

stubby

quadzilla wrote: »

Ack, no. .5 Ohm is too much resitor from my experience. .1-.2 is more like it. When I replaced my polyswitches with .5 Ohm the speaker sounded very, very veiled. The polys measured .2 Ohm, which would explain why .5 sounded like ****.

If you do decide to replace the polyswitches, measure their resistence and replace with the same value resistor. Or just leave them out. Some people prefer that sound. Or, if by chance yours do measure .5 Ohm, then yeah, go with that value.

Truth be told, I use jumpers on mine. I simply stated what others have suggested in other threads. And since replacing the stock binding posts, I may try a .2 ohm res. as some recordings can be on the bright side.

nooshinjohn

oliverbubbles wrote: »

Not a Home Depot near me. I got what is probably close; high density foam weatherstrip. Either way it has got to be better than what was on there. I'll investigate the Armacell and see what the difference is. If need be I'll change it out later, when I rewire.

I can see that the top and Bottom are bolted on. Can anyone tell me how the side peices come off? They appear to be snapped in the middle but I can't tell if they are attached to the top and bottom plates or just the sides.

Just get the Armacell... The compressibility of this tuff is top notch. PM me your addy and I will send you some.

Mr. Bubbles

Just get the Armacell... The compressibility of this tuff is top notch. PM me your addy and I will send you some.

Thanks for the offer. My brother in law works at a Home Depot. I'll get him to get me some. I looked into it and it seems to be similar to what I picked up but is labeled as a closed cell foam where as what I have is not specifically labeled as either open or closed cell or a combination.

My assumption is there will be little difference in sound using the rings since the sandwiching action of the baffle by using the rings and driver should actually couple the driver to the baffle more effectively and compress any type foam gaske t the point where the possibility of air escaping the pores or cells of the foam gasket would be almost impossible. Which brings me to a question I thought of earlier; has anyone tried adding a rigid ring in front of the driver to strengthen the frame and therefore a better seal as well as a better coupling of the driver/ baffle?

Joe08867

hamberg54 reported.

Carry On,

OldmanSRS

Any issue with deforming the driver mounting flange since amercell is thicker than the orginal gasket. Any need to retighten the screws after it compresses for a few days.

How would the 1" wide amercell work to damp the baskets as an alternative to dynamat?

Mr. Bubbles

OldmanSRS wrote: »

Any issue with deforming the driver mounting flange since amercell is thicker than the orginal gasket. Any need to retighten the screws after it compresses for a few days.

How would the 1" wide amercell work to damp the baskets as an alternative to dynamat?

I was curious about the driver flanges as well. That's why I asked (somewhere) if anyone had tried an additional support ring on the front of the driver.

I haven't tried the armacell on the baskets but don't think it would have too much damping effect. The Mortite may damp fairly well, but if you have to buy it you may as well get the Dynamat (Xtreme).

Joe08867

Lots of guys here (me included) use dynamat on the baskets. It is an easy mod that isn't horribly expensive and does give good results.

I would also suggest thin foam from a fabric store over Amercell or Mortite. It would be more like the original gasket and works better in my opinion than trying to cram something behind the flanges of the drivers and tweeters.

Mr. Bubbles

Finally! Updates to the SRS's. After finding the oxidation, and weak cabinet joints, I didn't feel comfortable using the speakers as they were so i stripped them completely. below is a list of what i did and what i now hear.

- re-glued/ sealed all cabinet joints and braces
- dynamatted all baskets of M/W's and passives
Actually layers the passives as i could still hear some ringing after 1 layer of dynamat on them. two layers outside spokes and one layer inside. two layers on back of basket behind spider. they are now as dead as a foam covered wiffle ball bat.
- epoxied all magnets to baskets
-installed t nuts as due to failure in machinery I couldn't make rings except by hand and couldn't afford Larry's currently. Did this on all M/W's passives and crossovers. Did not see the need on tweets as the plastic frame will limited tightening on those no matter the hardware type.
- replaced all mounting screws with larger hardware. #10 button socket head on M/W's and crossover and 1/4-24 button socket heads on passives. Did this to gain more surface contact between hardware and component as well as to make all hardware match.
-replaced all gaskets with high density foam gasket material. I was unable to locate Armaflex ( I know someone here offered to send me some, I would like to thank that person very much for the offer).
These were tightened in stages for complete compression of gasket material. After tightening I noticed what appeared to be a very slight deformation in the input cup between screws. I measured with calipers and this was indeed the case. I changed these screws to larger screws and drilled and added the original screws at even intervals between the original locations. The input terminal cups now have 8 mounting screws each instead of 4.
I then measured the M/W's baskets and though not visible there is a very slight deformation of the baskets between mounting screws. I will look in the future to implement a front support ring for the drivers to prevent this. Tweeter gaskets were replace with this material as well since original gaskets only showed compression around screw holes and did not appear to seal the driver at any other location.
- since i found the oxidation I checked all the wiring and connectors and found some of the wiring to have slight oxidation as well. i replaced all M/W wiring as well as interconnect wiring with 12 awg. Input from terminal cups to crossover and from crossover to drivers as well as crossover to interconnect at terminal cups.
- since I am not bi-amping and did not have money to purchase new quality binding posts currently i placed both high and M/W inputs to lower factory posts and used the upper posts for interconnects and am using 12 awg speaker wire for the interconnect. All internal wiring was left so as to be able to switch back to a bi-amp wiring set up once I can replace all binding posts and add a 3rd set for interconnect.
- Polyswitches were already gone when i got in there so i left them out.
- all tweeter wiring was left original but terminals were soldered to the wiring.
- all wood was sanded clean and stained dark walnut.
- All grille cloth was replaced.
- replaced 2 tweets that I borrowed from my 1C's for now as I found that 2 of the tweets dome material had come at least partially unglued from the face plate. I think i can fix this but was trying to finish this project and get my wife the house back.
- found the spider on 1 passive to be starting to crack around the former section. This was slight and not really visible until I heard it when I was feeling it's movement while it was out of the cabinet. this was repaired with cyanoacrylate gel. ( I think I spelled that right but maybe not) ( a fancy name for super glue). this seems to be working good but I am now looking for a replacement passive just in case. if anyone has one they want to get rid of please let me know.


Now to what I hear.
the soundstage seems to be as wide as a football field with fantastic dimiensional effect. depth of stage seems to be somewhat lacking. Probably due to the old crossover components.
Everything is extremely clear and detailed
Bass is lacking somewhat in the presence of the music but is clean and detailed in what is there. I find this perplexing currently as some music sounds to have some slight out of phase effect in the bass while other music does not sound this way. I do not currently have spikes and again the crossovers have not been modded or updated yet. I am sure these things will have some effect on this. Bass does become more prominent (as compared to the mids) as volume level goes up.
Very mid range heavy but not to the point of truly overpowering lows and highs, but definitely much more prominent than the lows and highs.

The wife is happy with the looks now and i am happy with listening to them until I can upgrade the crossovers and binding posts. I am currently making spikes and will add them soon.

chandler9a

Very extensive... You seem to be learning about these SDA's a lot faster than most.

Keep it up

cnh

He's certainly already done more than I will ever do. My 2Bs are stock and they're currently sitting in my closet. lol

Nice work! There are a lot of SDA 'technicians' on this site. You're in the right place.

Enjoy...maybe I'll break mine out and give them a listen this weekend (they're just too big and I don't have permanent space to set them up. The footprint requirements for the SDA effect requires a minimum of 13-14 feet of free wall space).

cnh

audiocr381ve

On my tile floors, adding spikes with pads made brought the speakers into "focus." I didn't get better bass definition, but the bass output was punchier and tighter. I highly recommend spiking them!

Joe08867

Audio, The problem with the bass could be the room itself. If the wall they are sitting on isn't insulated it could be sending a lot of the bass into it. I have found that to be an issue on one wall of my 2ch room.

Wall treatments can help so could but bass traps could really bring them into focus even more.

I agree Spikes are key.

jaygax

hello everybody. i registered to this forum because a friend of mine just gave me a pair of Polk Audio SDA2a speakers. it has one tweeter, two drivers, and one sub radiator?=thats the term its called right? its not a subwoofer. anyway, i used them for my front L & R channel. they sound amazing. i have a yamaha RX-A1000.

i have a lot of questions,
my yamaha doesnt have a 4 ohms to drive those SDA2a's. am i taking a risk of burning my yamaha? i just connect them using an 8 ohm load. the SDA's really sound good even when i disabled my BIC PL200 sub with the DSP sound effect set to stereo mode.

even if im running a 7.1 setup with additional two front presence speakers, i still want to experience what everybody here are talking about. the SDA effect. thats actually what those speakers are for, right? i have a couple of problems.

first, where the heck can i find those interconnect cables? or how can i really possibly make one? what materials do i need to make one?

second is, the risk of burning out my yamaha. i really dont understand a lot about amps and i read that there is a risk of burning your reciever when using an interconnect cable. what should i do?

without the SDA effect, they are just ordinary speakers and OLD. i've been saving for a pair of klipsch for my fronts when a friend of mine sent me a message from facebook about a pair of huge speakers sitting at her attic. what's really sweet is i got them for FREE!

so please if somebody can help me about this. i would really appreciate it that much. thank you. :cool:

Mr. Bubbles

jaygax, welcome to the Forum.

I am relatively new to these forums as well ( a couple of months). I also have a pair of 2A's that i originally thought were 2B's. However the 2A's sound better to me than either of my other pair of SDA's currently ( I also have the 1C's and SRS's). The 2A's are not as powerful but mine have a terrific sound, excellent balance and smoothness that the others don't currently have. i think it has a lot to do with the simplicity of the design.

You will not get the full effect or sound quality of these until you connect them with the interconnect cable. I read on here recently that Polk still has the cables for this model available. You can also make one by finding some blade terminals that fit the locations and simply using speaker wire between the cabinets. Be sure the terminals DO NOT get crossed.

If your Yamaha is not a common ground amplifier, you could damage it and possibly the speakers. If you are not sure you may want to contact Yamaha customer support and ask them.

There are varying opinions about using these in a home theater setup. In my opinion these speakers do not sound the best in a 5.1 or 7.1 system. 2.1 or 2 channel sound makes them shine. that seems to be the opinion of most members here that have commented on this that I have read about. However let me also state that some members also have stated that they like these speakers in a H/T set up so the best thing to do is listen for yourself and see if you like it.

Good luck with these speakers and enjoy the SDA ride.

Joe08867

jaygax, you are running a risk of killing that Yamaha, you can order the interconnect cable from Polk the number is in the upper right corner of the forum.

The SDA effect will bring those speakers to life. Right now you are only using them to about 50% of there potential. Fully running them with the interconnect is the only way to go.

jaygax

thank you oliver for the reply. i'll just try to make the cable myself. anyway, i really wont be needing that cable that much since i have a 7.1 setup and my yamaha has various sound field effects called DSP. my SDAs will just have to be front left and right channels. but im still curious about that SDA effect.

im saving myself for a pair of RTi A7. those would really complement my yamaha and the 7.1 setup without worrying about the ohms load factor. SDA's got 4 ohms while most of the speakers now have 8. im just using my SDAs for the meantime. lastly, money is really a great factor in building a stable and ear satisfying home theater!