Crossover upgrade on the SDA IA

Joe08867

I agree with Ben's post above.^^^^ The tweeters will need some time to break in. And after the crossover is done and also broken in they will improve even more.

Give them time to break in. Closet, Blanket, Moderate volume. These three things will help alot.

F1nut

You have to put some hours on any audio component before judging the sound, period.

candyliquor35m

Don't be stubborn. The only way you'll be able to hear and accurately describe the differences between the 2000 and the rd0 is to do a left vs right comparison.

MillerLiteScott

CL35. I totally disagree. I gave a pair of broken in RDO 194's to a member to try out for a while after listening to SL2000 for quite a while. That is the best way to compare the sonic qualities/differences of the two different tweeters. NOT A SL2000 IN ONE SPEAKER AND RDO IN THE OTHER SPEAKER.

Scott

heiney9

candyliquor35m wrote: »

Don't be stubborn. The only way you'll be able to hear and accurately describe the differences between the 2000 and the rd0 is to do a left vs right comparison.

Pffffttttt........ repeat from another ongoing thread.

So I guess you never listen to stereo recordings?. The method is flawed but if it blows your skirt up then by all means keep doing it.

I know when I demo a new TV I set them side by side with the same signal and close my left eye and use my right eye for the TV on the right; then I close my right eye and use my left eye for the TV on the left. Works every time even though the guys at BB and CC are calling the wagon to take me to a rubber room.

Running a mono signal, ie; using the balance for left and right for (2) different components is a piss poor way to determine differences because the exact same signal is not present on both the L and R channel; hence why the term STEREO is used.

For Carl:

Stereophonic sound, commonly called stereo, is the reproduction of sound, using two or more independent audio channels, through a symmetrical configuration of loudspeakers.

During two-channel stereo recording, two microphones are placed in strategically chosen locations relative to the sound source, with both recording simultaneously. The two recorded channels will be similar, but each will have distinct time-of-arrival and sound-pressure-level information. During playback, the listener's brain uses those subtle differences in timing and sound-level to triangulate the positions of the recorded objects.

Stereo recordings often cannot be played on monaural systems without a significant loss of fidelity. Since each microphone records each wavefront at a slightly different time, the wavefronts are out of phase; as a result, constructive and destructive interference can occur, if both tracks are played back on the same speaker. This phenomenon is known as phase cancellation.

H9

candyliquor35m

MillerLiteScott wrote: »

CL35. I totally disagree.

I respect your opinion and I hope it keeps working for you. I'm never going to convince you and you're never going to convince me so any further discussion should be about the details of why we like or dis-like the different methods.

When I try the listen and switch approach, I tend to only hear the positive factors such as less harshness or brightness.

When I do the left vs right method especially with tweeters, when I walk back and forth between the 2 speakers, I can key in on all the positive and negative differences between the 2 over and over again and confirm it fairly easily before making any final conclusions.

ben62670

CL you are all by yourself on your little save the SL2000 crusade, and you can't compare speakers with one done, and not the other.

dcmeigs

Here are some photos of the crossovers. The four boards are from the SDA 1As. Each cabinet has one dimensional array board and one stereo board. The boards themselves are interchangeable but have different components. The set of caps and resistors on the left are for the SDA 2B project. Those on the right (plus two 27uf not pictured) are for the SDA 1As. The two in the forefront have been stripped and the two in the background are original. The small electrolytic caps are the originals.



Here is a close shot of the clean stereo board and the array board stripped of the 27uf cap. The other components remain on the array board as the SDA tweeter will not be connected.



Here is the completed stereo board. I changed out the 18ga wire in favor of 14 gauge where the drivers are concerned but left the 18 gauge for the tweeters. I added an extra set of driver leads so as to avoid daisy chains.




And the array board.



I got them connected about 4pm yesterday and they did not sound too good in the first hour. I'll get out there and check on them later in the day. They have about 22 hours on them now.

dcmeigs

After 24 hours the sound is much better. I used a 3.5 ohm resistor in parallel with the 0.5uf cap in the tweeter section of the crossover and I was concerned that I might have too little tweeter (the sl2000 is disconnected). It actually sounds a little bright right now but I'll reserve judgment until next week. That's an RD0194 on the right (inboard). It's larger than the SL1000 by about 3/8" so a router was used to increase the size of cutout.

dcmeigs

Ok, now I'm pumped. The 1As have been locked up in my buddies house operating at good volume on XM radio constantly while he was away on vacation, so I now have about 150 hours on them. They really sound sweet now. It was such a relief to walk into that room and hear them now. I feel vindicated! (I'm spending someone elses money - oh the pressure...)

It's been a year since I have listened to these so I supose I'm really comparing them to my 2Bs, but I can say that the 1As now have a much more detailed and dynamic sound than before and the sound stage is greatly improved. I'm kind of a partisian, I don't think the sound stage is quite as dramatic as the 2Bs, but there is no question that it is very much improved by the modification.

I took the array tweeter out of service and I think that has a lot to do with it. I left the fuse holder in series with the array tweeter section of the crossover so I can slip in a fuse and listen to them again with both tweeters. I'll try to reserve full judgement until I have that opportunity, but the annoying busyness of the 1As SDA effect is gone. I used to unplug the interconnect cable on the 1As to and listen to try and figure out just what it was about the 1As that was bugging me. I'm not hearing any of that now.

I used a 3.5 ohm resistor in the tweeter circuit and was prepared to adjust that as needed but I think the 3.5 nails it. I found the 1As a little too bright before and I no longer do.

I owe thanks to DarqueKnight for all the great posts and schematics and to Ben, F1nut and everyone else who offered their input. This is an exceptional forum.

ben62670

Congrats. I am pleased that you are pleased:)
Well I think its time to relax, turn off the lights, and kick back while listening to Pink Floyd's Dark Side of the Moon:cool:

BTW that is an SL1000 tweeter;)

dcmeigs

F1nut wrote: »

1. Go with the 3.5 ohm.
2. You can not use the RD0198-1, you must use the RD0194-1.
3. Get rid of the fuses.
4. Get rid of the 750pF's. You won't need them anymore.
5. Yes, it's 0.5uF and yes, a poly will work well there.
6. Correct, no change.
7. Can't help you there.

The new tweeters are a vast improvement, period.

A gentleman PMed me about upgrades he is considering for his SDA 1As and the subject of the RD0198-1s came up. He is considering doing away with the dimensional array tweeter as I did (which I can recommend). I told him of your statement about not using the 198-1 tweeter, but I allowed that I did NOT understand why the TL crossover mod could not be used in this application as it is in the SDA-2B for instance, given that the DA tweeter is disconnected.

At the time of this post, the subject of eliminating the dimensional array tweeter had not come up. Given that the high pass crossover for the stereo tweeter is in parallel with the balance of the crossover network, why can't the 0198-1 be used with the TL mod and the 5.8 uf cap?

ben62670

I'd have to take a good look at the three different XO's involved to figure out how to implement the 198's into the XO. It isn't as cut and dry as you would think because the mids are different than with the newer speakers with the TL conversion. Long story short the 198's are considered a little better than 194's, but not worth the headache of maybe getting it right. Stick with the 194's;)

dcmeigs

ben62670 wrote: »

...the mids are different than with the newer speakers with the TL conversion. Long story short the 198's are considered a little better than 194's, but not worth the headache of maybe getting it right. Stick with the 194's;)

Ben,

Yes the 194 is a very good tweeter. This is really more about my trying to understand speaker design than the best tweeter for the SDA 1As or a reinvention of the wheel.

We could fill the pool with what I don't understand about speaker design, and I would gladly purchase and read the definitive text on the subject given a recommendation (Please...I mean it), but after considering your post, I think I might get your point.

That the differences in low pass XO design and driver selections suggests the possibility of a different crossing frequency and thus a different design goal for the high pass XO. No doubt a great deal of testing and thought on Polks part and a whole can of worms for the guy who decides to fool with it.

F1nut

I think you've got the idea, totally different animals.

candyliquor35m

I used sl3000's in my stock 2.3's for over a year and they sounded great. Then I got the urge to go back to the sl2000 and have no plans to use anything else.

My 2.3's with the sl3000: http://www.polkaudio.com/forums/attachment.php?attachmentid=13062

The sl3000 will give you about 90% of what the sl2000 gives you as far as detail, clarity and sound stage. The only way to know if you like the rd0198 better than the rd0194 is to try it.

ben62670

candyliquor35m wrote: »

I used sl3000's in my stock 2.3's for over a year and they sounded great. Then I got the urge to go back to the sl2000 and have no plans to use anything else.

My 2.3's with the sl3000: http://www.polkaudio.com/forums/attachment.php?attachmentid=13062

The sl3000 will give you about 90% of what the sl2000 gives you as far as detail, clarity and sound stage. The only way to know if you like the rd0198 better than the 194 is to try it.

He means well...

heiney9

candyliquor35m wrote: »

I used sl3000's in my stock 2.3's for over a year and they sounded great. Then I got the urge to go back to the sl2000 and have no plans to use anything else.

My 2.3's with the sl3000: http://www.polkaudio.com/forums/attachment.php?attachmentid=13062

The sl3000 will give you about 90% of what the sl2000 gives you as far as detail, clarity and sound stage. The only way to know if you like the rd0198 better than the rd0194 is to try it.

As stated a billion times the RD0198-1 is not the current replacement tweeter for Polk speaker models designed to use the sl2000 tweeter; the RD0194-1 is the correct part.

H9

F1nut

candyliquor35m wrote: »

I

No comment. As CL35 doesn't know the difference between a resistor and a cap, nor possess a basic understanding of why one tweeter is designed to work with one circuit and the other tweeter with another circuit, you have to take what he says with a grain of salt, if that.

dorokusai

I tend to take it with a shot of whiskey or heroin.

treitz3

Please don't let ************** ruin this thread. Its bad enough on the other threads. Think about the newbies that want to learn and don't know about the ignore feature.

Think I'll slide out now.....

candyliquor35m

heiney9 wrote: »

As stated a billion times the RD0198-1 is not the current replacement tweeter for Polk speaker models designed to use the sl2000 tweeter; the RD0194-1 is the correct part.

H9

You are absolutely correct but that doesn't persuade me from trying the rd0198 in place of the rd0194 just like I used the sl3000 instead of the sl2000 in my 2.3's for over a year. It's not any different than someone using a EQ to tailor his system to his own taste in sound.

Wasn't that a polk speaker that someone recently installed a rear firing tweeter in. I can't find the thread.

heiney9

candyliquor35m wrote: »

You are absolutely correct but that doesn't persuade me from trying the rd0198 in place of the rd0194 just like I used the sl3000 instead of the sl2000 in my 2.3's for over a year. It's not any different than someone using a EQ to tailor his system to his own taste in sound.

Wasn't that a polk speaker that someone recently installed a rear firing tweeter in. I can't find the thread.

One final thought to you Carl and you've heard it from me before; he didn't ask the question that you apparently felt you needed to answer. Your post has nothing to do with what the OP is asking or the rest of the thread is discussing.

Here's what he asked in case you forgot:

but I allowed that I did NOT understand why the TL crossover mod could not be used in this application as it is in the SDA-2B for instance, given that the SDA tweeter is disconnected.

At the time of this post, the subject of eliminating the dimensional array tweeter had not come up. Given that the high pass crossover for the stereo tweeter is in parallel with the balance of the crossover network, why can't the 0198-1 be used with the TL mod and the 5.8 uf cap?

Face

candyliquor35m wrote: »

You are absolutely correct but that doesn't persuade me from trying the rd0198 in place of the rd0194 just like I used the sl3000 instead of the sl2000 in my 2.3's for over a year. It's not any different than someone using a EQ to ruin his system.

Fixed.

Wasn't that a polk speaker that someone recently installed a rear firing tweeter in. I can't find the thread.

It wasn't a Polk speaker.

candyliquor35m

heiney9 wrote: »

One

No comment. My post is directly related to the topic being discussed which is using the rd0198 in place of the rd0194 with or without x-over mods.

I did this with the sl3000 in place of the sl2000 for over a year with no x-over mods and it sounded great. I'm not recommending it but I'm sharing my personal experience with the topic.

http://www.polkaudio.com/forums/showpost.php?p=842069&postcount=30

http://www.polkaudio.com/forums/showpost.php?p=854255&postcount=25

ben62670

Why would Polk spend so much having 2 different tweeters designed instead of 1? You were one of those kids who ate cat turds in the sand box weren't you?
Here we go with another thread filling up with the mindless rantings of a delusional idiot...

heiney9

Aye, Aye, Aye...............here we go again. I'm out of this one as I've had my rational say. Have fun guys, this isn't even close to being worth it anymore.

treitz3

Nevermind. 5 or 12 pages from now, they will still know nothing about what they came to learn....but on the other hand, they will know jack.

ajcutler53

dcmeigs:

Your documented process and experiences with the SDA-1A crossover mods has expired me to do the same. I have taken out the fuses to the dimentional tweeters, and have ordered the RDO-194 tweeters from Polk.

While not very experienced with electronics and circuit board work, I was able to successfully follow the SDA-1 to SDA-1A upgrade from Polk many years ago without any problems. So I am going to attempt the crossover mods. I have a few questions that would help me get started.

I am trying to put together the list of parts. You listed the following:

dcmeigs wrote: »

...
SDA IAs get:
1 each RD0194-1 silk tweeters, the other tweeter is disconected. I'm going to call it a passive twadiator mod (TM) and pretend it is important to the effect.:cool:
Sonicaps for the 12uf and 0.5 uf high pass.
Dayton 25+2uf caps for the low pass.
Mills 12 watt resistors.

1. I assume 27uF Sonicaps are also needed which were in your photos?

2. What brand 3.5 ohm resistor did you get? and which brand 0.5 µF capacitor did you get that is in parallel with the 3.5 ohm resistor on the stereo array board?

3. Are the following the Dayton caps you used?

DMPC-25 25uF 250V Polypropylene Capacitor
DMPC-2.0 2.0uF 250V Polypropylene Capacitor

4. Where do the Dayton 25 and 2uF caps get attached?, I didn’t see them on the SDA-1A schematic? Do they replace the 750 silver mica caps?

5. I did not see a 12 watt resister on the schematic for the SDA-1A, where do the Mills resisters attach?, and where would they appear on the schematic?

6. I didn’t quite understand what you hooked up the extra wires to that you used to avoid the daisy-chain? Could you provide a little more detail?

Thanks in advance,

Alan

ben62670

The 25, and 2 are parallel to get a total of 27uf. If you could get values closer together to equal the total you would be better off. Like 1 12, and a 15. The original resistors are 5w. The 12's are better.