SDA-CRS dummy subwoofers?

[antinucci]

:lol: Newbie Alert, Newbie Alert :lol:

OK, I realize this might be extremely stupid, but I inherited some SDA-CRS speakers (circa 1987) from my Dad. I have always loved the way the sound. I decided to remove (what I thought was) the "subwoofer" off the back and there was no electro-magnetic coil on the back of the "speaker". Is this correct or did my dad get ripped off?

http://www.systolic-usa.com/dummy_subwoofer.jpg


http://www.systolic-usa.com/speaker_front.jpg

My guess is that these are not traditional speakers and there should not be a magnet on the back. How does this work?

Why did I take the speaker off the back? Because I was thinking about making my own cabinets for my home theater... I have 5 NHT super zeros and want to make the SDA-CRSs the two main speakers that sit beside my 65"HDTV but I want them in the thin vertical cabinets (towers I guess). If I keep the same volume of space in the cabinets, should these sound OK? I want to mount the "subwoofers" on the sides of the cabinets.

http://www.systolic-usa.com/speaker_plans.jpg


http://www.systolic-usa.com/speaker_plans_2.jpg

[RuSsMaN]

It's called a 'passive radiator'. It is not supposed to have a magnet or voice coil. The purpose of the radiator is to share the acoustical load, and extend the low-end response of the other active drivers.

Polk used a lot of PR designs, which I believe combines the best of both worlds, between sealed acoustic suspension, and ported designs.

Acoustic suspension typically provides tight, accurate bass, and more useable response below the 3db downpoint BUT typically requires more clean power.

Ported tend to give a little more bass 'punch', and require less power, but response is sometimes sloppier, and although the 3db downpoint may be lower, useable response after 3b down is almost non-existent.

The pr designs, imo, utilize the best parts of both configurations..

Put that nice SDA back together, thats damn near blasphemous!!! Your Dad did NOT get ripped off....

Others will chime in, the CRS you have is a very sought after model among SDA enthusiasts.

Cheers,
Russ

[F1nut]

antinucci,

Welcome!

The speaker in question is called a passive radiator (like a sub woofer) it operates from the sound waves from the mid-drivers.
Do you have the interconnect cable for the speakers? As for your idea.....I wouldn't ruin a perfectly good pair of SDA CRS speakers. There are plenty of people that would buy them and you could spend the money on something else that suits your needs better.

[F1nut]

Originally posted by RuSsMaN

Put that nice SDA back together, thats damn near blasphemous!!!
:lol: :lol: :lol: You tell'em Russ!

[antinucci]

Originally posted by F1nut
antinucci,

Welcome!

The speaker in question is called a passive radiator (like a sub woofer) it operates from the sound waves from the mid-drivers.
Do you have the interconnect cable for the speakers? As for your idea.....I wouldn't ruin a perfectly good pair of SDA CRS speakers. There are plenty of people that would buy them and you could spend the money on something else that suits your needs better.

Thanks for the welcome!

Yes, I have the interconnect cable.

>I wouldn't ruin a perfectly good pair of SDA CRS speakers.
Wow, I did not think these speakers were that hot of a commodity!

Thanks for the tip!

[F1nut]

If you want to sell, put them on the flea market. Do you have the stands? Have you ever heard these play on a 2 channel system?

[antinucci]

Originally posted by F1nut
If you want to sell, put them on the flea market. Do you have the stands? Have you ever heard these play on a 2 channel system?

I don't have the stands. I was just upstairs measuring things to see if I could keep the original cabinets and just make stands myself instead of redoing the cabinets. I could keep the original cabinets if I situate them vertically (i.e. turn them 90 degrees from correct position). Is this a really bad thing for audio quality?

What do the original stands look like?

These speakers have only been connected to my left and right channel of my home stereo system - they are wonderful in that system. I just recently tried them in my home theater and loved them, so I want to convert them so as to play nice with my home theater. This involves thinner cabinets and perhaps some satin black paint :eek: to cover the wood grain exterior (which is pretty badly worn - but salvagable I guess)...

Thanks for the info...

[hoosier21]

You have a pair of Polk CRS+ speakers, they come from the Polk SDA line of speakers. SDA = Stereo Dimensional Array. The speakers were made "short and wide for a very good reason and turning them up on the sides will kill the SDA effect. They have that interconnect cord to direct some of the right channel signal to the left speaker and some of the left channel signal to the right speaker.These extra signals are fed to the outside 6.5" drivers (right speaker's most right driver and the left speakers most left driver) out of phase from the reagular stereo drivers and creates a crossfire of sound. you hear in phase music from the right speaker in the right ear and before that sound makes it to the left ear it is intersected with the out of phase right channel sound that is coming from the left speaker's outer driver and creates a null (meaning your left ear will not hear the sound from the right speaker. The same happens from the left side. If this is done correctly it will be similar to listening with headphones and give you great stereo imaging and a very wide soundstage. Please don't mess with them, ENJOY them as is. Do a search I give some proper set up information on another thread, these need to be set up correctly for all this SDA to work, good luck.

[hoosier21]

watch out boys, this guy has only 3 posts and has has used the quote feature, posted a picture, used the smiley's and colored text, hell he can even spell

welcome antinucci

[nascarmann]

These guys are pulling your chain.....The speakers you have are out of date.....I will give you $250.00 just to help you get a new pair of speakers. No..no..don't thank me....I'm glad to help you out. Email me here! (ksr999@earthlink.net)

[F1nut]

The stands are a black metal frame and are made to put the speaker at just the right height which is very important. Someone else can give you the measurements. Please don't paint them! If you need some tips on restoring the finish I'd be happy to help. I see that you liked them on your 2 channel system which is what they were designed for, so maybe you can go shopping for some new Polks for the HT. I believe Polk can provide a owners manual for the CRS if you're interested, just give them a call.

[F1nut]

Originally posted by nascarmann
Email me here! (ksr999@earthlink.net)

Yeah, right!!! :lol:

[nascarmann]

Yeah, right!!!

Maybe a little too much?:D

[F1nut]

Maybe :D :D :D

[DEvans]

I have a set of the SDA (CRS) compacts also and have had them for years on my 2 channel system. Last year I added a set of RT25's to the rear for watching movies.

I have now moved into the 21st century (I think), by purchasing a new surround sound receiver. I have now added a PSW350 sub and CSi30 center. I know plan on moving my 20 year old two channel amp and the SDA's out of the den and into a larger living room for music only. The SDA's will be replaced with another set of Polks for the surround sound system, but not sure which to use (need to mount the new ones high up and on the wall for space reasons).

I agree with those that say keep them as is. I've had mine for a very long time and will not get rid of them. I also have the original boxes/manuals and have a set of stands, but not sure if the stands are original (square metal tubing with two up rights, square tubing base at top and bottom and pins at bottom to puch through carpet).

Dave

[antinucci]

OK men. I get the drift. I will be restore them back to original configuration, refinish the exterior, get the manuals, and buy or make the proper-height stands. Thanks for all your input!

This is a great forum. I will visit often.

I am newbie here, but I frequently use the V-drums Forum (http://www.vdrums.com/forum). Here is my other hobby:

http://www.systolic-usa.com/my_kit.jpg

[F1nut]

Originally posted by DEvans
(square metal tubing with two up rights, square tubing base at top and bottom and pins at bottom to puch through carpet).



Yep, that's them......Welcome Dave.

[antinucci]

UPDATE: here are the finished products.

http://www.systolic-usa.com/speaker1.jpg

http://www.systolic-usa.com/speaker2.jpg

http://www.systolic-usa.com/speaker3.jpg

http://www.systolic-usa.com/speaker4.jpg

Yes, I painted them black. A beautiful piano black finish. I love it.

Yes, they are upright on 29" stands. I did a lot of playing around with the positions I personally can't tell the difference if they are on their sides (i.e. their "correct" position) or if they are up right. They sound DAMN good either way.

Great speakers... Sorry if I "defaced" them too much and sorry for the "blasphemy".

[F1nut]

I'm...I'm...I'm speechless.....I feel a tear forming...have to go...

[MxStYlEpOlKmAn]

DUDE!!!!!!!!---DUDE--- YOU...NEED...TO...WORK...FOR...POLK...AUDIO!!!!!!! !!!

and you need to repaint all their mother crackin ebony speakers to that black piano finish...thats f-n' awesome dude!