SDA CRS speakers interconnect not working*

Brusco

I have a couple SDA CRS speakers and the interconnect is not working. While having the front speakers making sound from my receiver, I tried stuffing speaker wires into the interconnect jacks but could not get the interconnect speakers (rear) to make any sound. I even made my own interconnect cable using speaker wire and gold plated spade plugs. The front speakers alone seem to lack bass. I presume the rear speakers relay more of the bass. I wouldn't know since i haven't heard these working properly yet.
Does Polk still have support for this old stuff? Any suggestions?

TennMan

Are you trying to connect the front speakers to the rear speakers with the IC cable. IF so it is not meant to work that way. The IC cable goes between 2 front SDA speakers or the two rear SDA speakers. Not front to back.

westmassguy

Brusco wrote: »

I have a couple SDA CRS speakers and the interconnect is not working. While having the front speakers making sound from my receiver, I tried stuffing speaker wires into the interconnect jacks but could not get the interconnect speakers (rear) to make any sound. I even made my own interconnect cable using speaker wire and gold plated spade plugs. The front speakers alone seem to lack bass. I presume the rear speakers relay more of the bass. I wouldn't know since i haven't heard these working properly yet.
Does Polk still have support for this old stuff? Any suggestions?

You need to get your learn on about SDAs, and how to connect them properly: http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf

PolkieMan

Yes always "read up" before you start sticking wire in holes really bad things can happen :-)

Brusco

Sorry for any confusion but I'm trying to use the interconnects the way they were intended. So the interconnects on these speakers are not working. Perhaps the next step is to start taking them apart to see if there's anything obvious that has come loose. I'm not technical and can't read schematics, but have done some light soldering.Thanks for the handbook.

westmassguy

Those are 2nd generation SDA-CRS. The Blade/Blade connector must be connected correctly. Large blade to large blade, small to small, otherwise it won't work. The rear speaker is a Passive Radiator, not an active woofer. Your amp must also be common ground.

Brusco

I connected > large to large / small to small. I can't hear a difference with the interconnect plugged in or out.
Passive Radiator? Are these interconnects so subtle that maybe I think they're not working and maybe they really are? My amp is anAcurus 250. My Pre is a Aragon 24K. I wouldn't know common ground if it hit me on the head. How do you tell?

TNHNDYMAN

Maybe if you share your location, someone local to you could provide more assistance. The interconnect cable that came originally with the speakers is needed not just speaker wire. Also the "front" speakers are the only active drivers in those. The large thing on the back is a passive radiator. Yes it does help with the lower frequencies, but it is not a true driver connected to the crossover that you are assuming (I think and now I'm assuming, lol). At higher volume levels and with bass heavy tracks of music you could remove the grill cover off the back and see the passive radiator move a little, but don't expect to see excursion like you would with a 12" subwoofer.

If you get the interconnect cable figured out, the next step to verify the SDA drivers are working as intented would be to use a receiver with balance control adjustment and see if you are getting the intended effect. Of the two front 6 1/2" drivers, one is an active drive for that speaker be it left or right and the other is an sda driver for the opposite speaker. Again it looks like you need to read some more thru the manual to understand it a little better and until you get the proper interconnect all bets are off. Hope this helps a little.

TNHNDYMAN

Please stop trying to play them until you get a proper interconnect to go between the speakers or have someone with more knowledge than myself (Westmassguy would be a great resource) to possibly help you create your own. Without it you will not get the SDA drivers to work at best and worst case you will destroy the crossover and have flames shooting out your speakers. SDA's are not normal speakers and need to be setup properly.

[Deleted User]

Hello,
Here is a link to a previous Club Polk thread, go to post #9 and there will be a second link that will take you to a way to check the performance of any SDA speaker:

http://www.polkaudio.com/forums/showthread.php?55888-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-Stereo-Dimensional-Array(SDA)

Regards, Ken

Brusco

Hi Ken,
Thanks for the link to the SDA troubleshooting guide among others. If someone knows more about the design of the stock interconnect and why my homemade cable is not sufficient I'd be interested in hearing why. Again mine is basically 12 gauge speaker wire with gold plated spades on the ends.

F1nut

It's likely that one or more of the blade sockets is too loose or broken. You'll have to open up the speakers to check that.

Are these interconnects so subtle that maybe I think they're not working and maybe they really are?

That's a big no.

My amp is an Acurus 250. My Pre is a Aragon 24K.

You said you are using a receiver in the first post.

I wouldn't know common ground if it hit me on the head. How do you tell?

When your amp blows up and/or the speakers die, you'll know the amp wasn't common ground. Or, you can test with a VOM on the negative outputs on your amp, turn it off first.

PolkieMan

Yes use a standard stereo receiver, if you have one, till you get the SDA cable problem sorted out.
I can tell you when I hook and unhook the SDA cable I hear a change, in volume in the mid frequency's like the sound when a mid driver is working and then not. People do strange things to their speakers it could even be that the SDA drivers are bad or unhooked.
Or even rewired?

westmassguy

As Jesse points out, the sockets my be bad, also the male spades on the original interconnect cable are much thicker than a standard quick connect, and may not be making good contact. You'll need to pull both drivers to gain access to the two part crossover. Be advised that externally the cable is polarized. Large blade to large, small to small. Internally, the wires should be reversed on one speaker. This is normal. Everything else on the crossovers are wired the same between the two.

Brusco

I ordered the interconnect cable as recommended.. I just haven't received it yet.

I also have a NAD 2200 power amp that I would like to power the SDA's with. I'm not sure if this amp is common ground or not. It has a couple references to this in the NAD manual but I don't have a clue what it means? I'm lost when it comes to technicalities like this. Multimeters even confuse me more. Can anyone tell by these images from the manual if this is specifying whether this is a common ground amp or not?

Schurkey

Brusco wrote: »

My amp is anAcurus 250. My Pre is a Aragon 24K. I wouldn't know common ground if it hit me on the head. How do you tell?

Very fine equipment. My compliments.

The 8000-series Aragon power amplifers have 20 ohms of resistance between the two negative terminals. My hunch is that the Acurus amps (both companies were divisions of Mondial Design) is similar--a deliberately-inserted resistance between the negative terminals. Many other manufacturers do this also. A jumper wire from one channel's negative terminal to the other channel's negative terminal is required with Blade/Blade SDA speakers; and makes a HUGE improvement in sound quality.

Just to ask the question...does your Aragon 24K have the cube-shaped volume control, or the round-with-blue-sticker volume control? The round volume control is preferred.

Photo provided by Be_godwin, displayed at
http://www.ebay.com/gds/Aragon-Preamps-and-Home-Theater-Processors-A-primer-/10000000001649104/g.html

Brusco

Schurkey,
Thanks for the compliment. To be honest I never had the Aragon 24K open to see which volume control it has. I've only had the preamp for a few months now. I have a shot of the Acurus opened up if that can give you any clue to the jumper you speak of.
I'm not sure if that would be stock or a mod that would have to be done?

F1nut

The jumper is a piece of high quality speaker wire that you place between the negative binding posts of the left and right channels on the outside of the case.

That said, it's been the experience of most people that while allowing the use of a non-common ground amp with blade/blade SDA's such as yours, the sound quality suffers. YMMV.