SDA CRS modifications

[maandjojo]

Just purchased a pair of the CRSs' and after reading about the improvement mods for some of the other SDAs' I was wondering if there are any mods that have or can been done to the CRSs'. I can handle a soldering iron but just need specific instructions in changing any circuitry.

Thank you,
Joe

[Lasareath]

Hey Welcome to the Club!!!

Does the cable connecting the two speakers have two blades on it or is it a Blade and a pin?

Is there two tweeters per cabinet or just one?

[maandjojo]

Blades and two tweeters per.
Actually I have a member for a bit but mostly lurked and had one of the original SDAs' back in the 80's, sold them to get the LSI25 plus center and surrounds. They are great for 5.1 but miss the SDAs' for pure stereo.

Anyways thanks for your info and more to come,
Joe

[ben62670]

First try disconnecting one of the wires on the outer tweeter. See if you like that more. I would definitely replace the caps and resistors in the crossovers, and get the new replacement tweeters from Polk. Mention that you are a club Polk member to get the discount;)
Ben

[Tony M]

Maybe Dorockusai will help you out. He has a method to upgrade;)

[schwarcw]

First try disconnecting one of the wires on the outer tweeter. See if you like that more. I would definitely replace the caps and resistors in the crossovers, and get the new replacement tweeters from Polk. Mention that you are a club Polk member to get the discount;)
Ben

Ben,

If I recall, I think that you need to add a resistor to the active tweeter to "tame" the additional signal from the disconnected tweeter.

[schwarcw]

PS Welcome to Club Polk! Enjoy those CRS speakers, they are special.

[ben62670]

Ben,

If I recall, I think that you need to add a resistor to the active tweeter to "tame" the additional signal from the disconnected tweeter.

Actually you need to decrease the resistor to 2.7ohms in single tweeter mode, and if this is done you can piggy back that resistor with a 5.8uf cap to do the TL mod.

[ESavinon]

Hi carl!

[schwarcw]

Hi Ed!:):D

[ESavinon]

Good to see you up this late.

[schwarcw]

Actually you need to decrease the resistor to 2.7ohms in single tweeter mode, and if this is done you can piggy back that resistor with a 5.8uf cap to do the TL mod.

On the CRS? I thought you needed to change drivers, tweeters, etc. Are you sure you are not thinking the CRS+?

[ben62670]

Actually you need to decrease the resistor to 2.7ohms in single tweeter mode, and if this is done you can piggy back that resistor with a 5.8uf cap to do the TL mod.

Please disregard this post!
Thanks Carl. I double checked the diagram for this particular speaker and it has 6.5, and 7 ohm resistors in the XO. A drop to 2.7ohms would make them too bright, and the TL mod works with the 2.7r resistors only:o

[maandjojo]

Thanks for the responses thus far, hopefully you all can carry me thru this.
If you would, please bounce things off Ben, whatever I do I'd like it to come thru Ben, its much easier to get the correct steps and info from one person.
You know that I have the 2 tweeters and thats where I will start first. Realize I am going to do what you tell me, unless I feel its beyond my capabilites. I can handle soldering and have had to do some kluge work on the job so no problems there. Not good at modifying cabinets unless its real easy.
I will first order the better tweeter, should I order one or two for each cabinet.
If there is something else I should do first please give a holler, not too loud, no need for the wife to hear.

Thank you,
Joe

[ben62670]

I would just disconnect the outer tweeter for a while. The highs will be slightly attenuated that way, but the imaging should improve. If you like it with both tweeters that is cool too. People like it both ways. As for the other guys helping out it does help me too(thanks again Carl). There are some real knowledgeable people here.
Ben

[maandjojo]

Sounds like a plan. Didn't receive them yet, hopefully they will be delivered on Friday.
I will hook them up first using both tweets and give a listen for a day or so, then switch over to one tweet. After that I will write back.
By the way folks I do appreciate all the comments and help and no doubt there are quite a few of you that have a great deal of know how on the subject. It should be fun picking your brains.

Thanks to all,
Joe