SDA-CRS Mono Modification Advice

wrich22

I have purchased a set of SDA-CRS's with 2 SL-2000 tweeters and 2 MW-6503 woofers in each speaker. I have already converted them to polyproplyene capacitors and mils resistors and eliminated the poly switches.
and haved used them as center channels with and without without the interconnect

I would like to convert to mono speakers to use as dual center channels. I ran across one post that said just connect the Dimensional ground to the the Stereo ground in each speaker and eliminate the cable. I have tried this using jumpers. Seems to sound better.

I was wondering if anyone has done it a different way. I notice the the SDA
and stereo tweeters are wired slightly differently. The woofers appear to have the same wiring scheme.

The SDA-CRS schematic is posted on this forum thread for reference.

My main front speakers are SDA-SRS's that use the same drivers.

I use SDA Stereo for Music and surround sound with the center for movies and the center for TV

Any advice would be appreciated. Thanks

Bill

DarqueKnight

I ran a pair of CRS+'s for dual center channels for a while, then I replaced them with dual LSiC's, then replaced the LSiC's with dual LSi9's. I would still be using the dual CRS+'s if not for their bulk. I switched to smaller speakers strictly for aesthetic reasons. Of course, the dual CRS+'s were perfect timbre matches for the SDA SRS's I am using for front speakers in my HT.

I rewired the CRS+'s dimensional drivers to be in parallel with the stereo drivers. This dropped the nominal impedance from 6 to 4 ohms, so if you do this, make sure your amp is comfortable with low impedances.

Forum member Larry Chanin is using a pair of CRS+'s in his home theater, but I don't recall if he rewired the drivers. Here is a link to his home theater page:

Larry Chanin's Home Theater

wrich22

Thanks for the input. I effectively have the drivers in parallel, with my jumper and have plenty of power. Driving with an modified XL-600

The question I have have is the stereo tweeter has a 5.6 Ohm resisitor with a .5uf capacitor across it prior to the 12uf capacitor, wheras the dimensional tweeter just has a 7.0 ohm resisitor before the 12uf capacitor. Should I make them the same, and which should I use

DarqueKnight

Polk found that the dimensional tweeter wasn't needed for true stereo reproduction and in fact sometimes introduced unnatural artifacts, thus it was deleted from subsequent CRS versions. Since you will be running a mono signal, the dimensional tweeter is even more redundant and you could just disconnect it.

You might also consider wiring the dimensional tweeter in parallel with the stereo tweeter, but I don't know if this would drop the impedance too low.

wrich22

Right now I have the woofers and both tweeters wired in parallel, however as I stated before, the two woofers have the same circuit componets. Where as the tweeters have
a different resistor capacitor on the incoming signal

I would like to make them the same but not sure which way i should go. What is the purpose of the .5uf capacitor across the 5.6 ohm resistor on the stereo tweeter. should I make the dimensional side the same?

I have looked at several other SDA schematics some have .5uf cap and some don't

Thanks,

Bill

ben62670

I modded some SDA's to drop the dimensional tweeter. As DK suggested disconnect the Dim tweeter, and also you can change the stereo resistor to 3.5 ohms seeing you are only using one tweeter. This will bring the stereo tweeter up to the volume level of the mid woofers. I would remove the .5uf cap.
Ben

wrich22

Thanks, Ben

So I will end up with two woofers and crossovers wired in parallel, and one tweeter with a 3.5 ohm input resistor, no capacitor bypass, and I will disconnect the other tweeter. Right.

Thanks,

Bill

ben62670

You are talking per speaker correct?

wrich22

yes, for each speaker one tweeter and two woofers

ben62670

you got it:)

kimosabe

ben62670 wrote: »

you got it:)

Hi Ben,

I saw your old thread about the use of crs as a center channel. I have the older 2 tweet/2 mid CRS. I am not too keen on opening and rewirig my speakers, if i wired the crs pair in parallel, will they be an effective center channel? without the sda interconnect only the inner tweet will function right?

Ryan