Turning normal speakers into SDA’s

mlistens03

Stupid question, I know. I thought about this earlier today. Basically, what is to keep me from getting a set of LSi 7’s, and somehow attach them to the side of the LSi’s, or set them on top, and then design some sort of something to do exactly what the old SDA crossovers did? And, what’s to keep me from doing this to any speaker? I could have the first (and possibly last) pair of LSDA 25 speakers (made up that model number on the spot ), or I could have Mission Freedom SDA 770’s, the opportunities are endless.
But before I do anything, I need to understand how the SDA circuit works. How does it do what it does? How does the information that is supposed to cancel out the sound from the opposite speaker not cancel out the information from that speaker on mono tracks?
And then, what would be the challenges involved with this idea?
If this is the most stupid idea I’ve ever had, sorry for wasting your time, but I couldn’t find anything on the web, and I was too curious to not ask.
I was also thinking, if I got some SL2500’s I could have Polk LSDA 25TL’s, or Mission Freedom SDA 770TL’s.

Viking64

I would think that the extensive research and development/trial and error required to have even moderate success would require way more money and experience than you could muster.

Also, consider that production SDAs were designed to be just that. Taking other speakers and trying to "impose" SDA characteristics on them would likely prove to be a poor starting point for DIY SDAs.

I hope that makes sense.

Viking64

I'm not trying to throw this back into your face, but this comment you made likely applies to this SDA project at least 10 times more than it did regarding tweeters.

mlistens03 wrote: »

I don’t know enough about speaker design....

SDAs are finely-tuned cabinets with the perfect recipe of drivers, tweeters, passives, and crossovers. I'm not saying it can't be done, but it would be much easier to just buy a pair of real SDAs rather than throwing money away in a vain attempt to replicate greatness.

mlistens03

Viking64 wrote: »

I would think that the extensive research and development/trial and error required to have even moderate success would require way more money and experience than you could muster.

Also, consider that production SDAs were designed to be just that. Taking other speakers and trying to "impose" SDA characteristics on them would likely prove to be a poor starting point for DIY SDAs.

I hope that makes sense.

Totally makes sense. I thought of a few issues with my idea, but I had come up with ways around them.
My initial thought was “if this doesn’t work out, then I’ll end up with a ruined pair of speakers”. Then I thought about Polk’s sound bars. They use the SDA tech, and they do it actively, so what’s to keep me from designing some form of and active SDA circuit? (Well, experience, but maybe someone like VR3 or westmassguy.)
And, I obviously am not the expert on this matter, but isn’t the SDA effect caused by the SDA drivers being wired out of phase, and then receiving the signal from the opposite speaker? What’s to keep me from simply getting a second set of speakers and wiring them out of phase with the opposite speaker?
Also, just in case it seems like it, I’m not trying to argue. I’m just asking, because, quite simply, I’d like to know.
I also was thinking it would be way beyond my budget, but time for research and testing is an easy thing for me. So if I can find a source of income, it could be possible.

mlistens03

Viking64 wrote: »

I'm not trying to throw this back into your face, but this comment you made likely applies to this SDA project at least 10 times more than it did regarding tweeters.

mlistens03 wrote: »

I don’t know enough about speaker design....

SDAs are finely-tuned cabinets with the perfect recipe of drivers, tweeters, passives, and crossovers. I'm not saying it can't be done, but it would be much easier to just buy a pair of real SDAs rather than throwing money away in a vain attempt to replicate greatness.

I know, but I wasn’t necessarily talking about me, more someone else who knows what they are doing,
I also didn’t realize so much design had to go into them for the SDA effect to work, I thought they basically had to design a good normal speaker, and then change two drivers to play the SDA.
I didn’t say I thought it would be a working idea, and I didn’t think it would, but I was curious enough to ask if it would be at least conceivable. I now see that I am wrong. Feel free to continue to tell me how I’m wrong, I’d be interested to see what I missed when I was thinking about this.

Viking64

I'm not trying to dissuade you from trying. And there are several members that would know more about the feasibility of such an endeavor than I.

Trey (VR3 Mods) has a link to a PDF of DarqueKnights SDA handbook here:

http://vr3mods.com/LCSDAUpgrade.php

The Vintage Speakers page has stickys of threads that have wiring schematics of most (if not all) SDAs.

This link should work:

http://forum.polkaudio.com/discussion/55888/polk-audio-speaker-wiring-schematics-more-stereo-dimensional-array-sda#latest

mlistens03

Viking64 wrote: »

I'm not trying to dissuade you from trying. And there are several members that would know more about the feasibility of such an endeavor than I.

Try (VR3 Mods) has a link to a PDF of DarqueKnights SDA handbook here:

http://vr3mods.com/LCSDAUpgrade.php

The Vintage Speakers page has stickys of threads that have wiring schematics of most (if not all) SDAs.

This link should work:

http://forum.polkaudio.com/discussion/55888/polk-audio-speaker-wiring-schematics-more-stereo-dimensional-array-sda#latest

To be honest, I wasn’t going to try unless you guys said something like “yeah, that’ll totally work, go for it!” Because I don’t have the funds to lose one of my good sets of speakers if I screw something up, which is overwhelmingly likely.

KennethSwauger wrote: »

The best approach would be to set up an amplified SDA arrangement. You would connect a speaker wire to the left and right positive terminals on your main amplifier or receiver. This is the "difference signal" between the two channels. This would be connected to a simple 10:1 voltage divider (a 1k resistor in series with a 10k resistor). This would reduce the difference signal to a line level signal, this would be fed to an aux input on an integrated amp or receiver. A pair of smaller speakers would be connected to the amp/receiver in opposite polarity to the main speakers. The treble would be reduced on the amp/receiver and the two speakers would reproduce the difference information and the level could be adjusted and placed to the sides of the main speakers.
This would be an active SDA system, similar to what was done in the SRT system.

I think I might try this, because all I would need would be the resistors, I have everything else. Thanks!

warren

Wow !!!

HzTweaker

Looking forward to hear how this turns out!

heiney9

1000 times easier to just buy SDA's

mlistens03

heiney9 wrote: »

1000 times easier to just buy SDA's

True that. But, what if I wanted SDA’s that would sound like LSi’s, or Mission 770’s, or something else? Or if your in an area where it’s hard to find SDA’s, you could do this instead.
I don’t think I’m gonna modify my speakers, because I simply don’t trust my skills enough to not ruin my speakers, but I am gonna try and do what Ken suggested I do above.

tonyb

Good luck with that, but personally I think it's a huge waste of time and materials and the outcome will be less than desirable.

If you want SDA's, then buy SDA's. If ya want a speaker to sound like LSI's, then buy LSI's. Not that hard really.

mlistens03

Also, this was meant as more of a theoretical question, as in, is this possible. I am going to try and go through with Ken's idea, simply because the odds that I would ruin anything with a design the simple are low. if it works out, I will find a pair of LSi 7's to use for the project. I also think it would be a fun project to do, and then end up having a unique pair of speakers.

mlistens03

tonyb wrote: »

Good luck with that, but personally I think it's a huge waste of time and materials and the outcome will be less than desirable.

If you want SDA's, then buy SDA's. If ya want a speaker to sound like LSI's, then buy LSI's. Not that hard really.

I have a set of CRS's, although I think it'll be a fun project. (I also don't have anything better to do this weekend. ) With the idea that Ken posted, it'll cost me a dollar for four resistors, and then I'm good to go. Worth a try, and if by some miracle it works out, I'll be a happy camper.

mhardy6647

tonyb wrote: »

Good luck with that, but personally I think it's a huge waste of time and materials and the outcome will be less than desirable.

If you want SDA's, then buy SDA's. If ya want a speaker to sound like LSI's, then buy LSI's. Not that hard really.

Funnily enough -- I have the same reaction whenever I see or hear someone talking about soiled state hifi components with tubelike sound.

heiney9

This question has been asked a hundred times, no it's not worth it in both time and $$$. Even if you do what Ken suggested, it's not going to sound like a pair of classic SDA's.

It's your time and your dollar, so have at it. But it's not going to turn out like you want it to if you are looking for that classic SDA experience.

Matt Polk did it at this house with his own 2 pairs of LSi9's and very complicated and large crossover network.............................

...............but then, he's MATT POLK, he knows a thing or two about speaker design.

H9

mlistens03

heiney9 wrote: »

This question has been asked a hundred times, not it's not worth it in both time and $$$. Even if you do what Ken suggested, it's not going to sound like a pair of classic SDA's.
I understand this.
It's your time and your dollar, so have at it. But it's not going to turn out like you want it to if you are looking for that classic SDA experience.
I’m not necessarily looking for an identical experience. I simply want to see if I can improve the soundstage of my speakers even in the slightest.
Matt Polk did it at this house with his own 2 pairs of LSi9's and very complicated and large crossover network.............................

...............but then, he's MATT POLK, he knows a thing or two about speaker design.
At this house? As in, your house? That’s cool.
H9

I understand it probably won’t work as well as the original SDA’s. I simply want to see what I can do for the soundstage of my speakers, whichever those may be. And it’ll be a fun, simple project.
Thanks all for your advice, I’m gonna try this out and we’ll see how it goes. I’m guessing it’s gonna not work, but for a dollar and a few hours, I’ll happily give it a go.

nooshinjohn

Better amplification and line stage will serve you better than buying more speakers and an extra amp to run them...

mlistens03

nooshinjohn wrote: »

Better amplification and line stage will serve you better than buying more speakers and an extra amp to run them...

I already have another set of speakers and amp. If i didn't I wouldn't do this, but it'll be a dollar for resistors and time. a price I'm willing to pay. The speakers aren't LSi's, but they sound similar and will work for testing.

mlistens03

Will do! thanks.

codycatalist

Have fun dude but I tend to side with @nooshinjohn, what made the biggest difference in sound stage was better amplification. However my Adcom costs $119 more than your idea is currently projected at so have fun dude!

I like how your mind works, I wish I had that sort of curiosity anymore. When I first got here I was all about learning everything I could...then I heard (read) @mhardy6647 talk and was like well just tell me if it will sound good or not

mlistens03

codycatalist wrote: »

Have fun dude but I tend to side with @nooshinjohn, what made the biggest difference in sound stage was better amplification. However my Adcom costs $119 more than your idea is currently projected at so have fun dude!

I like how your mind works, I wish I had that sort of curiosity anymore. When I first got here I was all about learning everything I could...then I heard (read) @mhardy6647 talk and was like well just tell me if it will sound good or not

I honestly have no complaints about the sound stage of my speakers, and I plan on better amplification anyways, I plan on this simply being a fun and simple project with (hopefully) good results. If it doesn’t work, then oh well, I’m out 3 hours and $1 for resistors. And if it works, I’ll continue to use it, as better soundstage can never hurt, right?
I sometimes like to pretend I know exactly what Doc is talking about...
Kidding, I usually understand what he is saying. I do really like how much detail he gives, I can feel my IQ going up when I read his posts.

mlistens03

KennethSwauger wrote: »

I applaud your willingness to experiment in the face of such woeful opinions. As a first step you might try removing your left and right speaker wires from your amp. Then take a single speaker (doesn't matter what kind of speaker, really) then connect a wire to your left positive terminal on your amp and a second wire to the right positive terminal on your amp. Then connect these two wires to your speaker, it doesn't matter which wire is connected to positive or negative. Now play some music and you'll hear the difference information coming from that speaker. It should sound like music coming from a distant location in your room.

@KennethSwauger , just making sure, you connect the positive terminals to two pieces of wire, then connect those wires to the positive and negative connectors on your speakers?

mlistens03

I just tested what you said above, and it worked! Only stereo effects came through, nothing that was in both channels.
Thanks! I’m gonna go to HobbyTown tonight and get some resistors.

krazypolk

Well after reading all this talk about reinventing SDA's it got me motivated. I've got some free time next week so I'm going to try and reinvent the wheel. I'll let you guys how it turns out.

Get it? Turns out.

verb

As an alternative, what about Carver’s Sonic Holography amps? Plug and play, will work with any speakers. Not quite to the level of SDA, from what others have opined, but certainly less rework and iteration. Just a thought.

mlistens03

krazypolk wrote: »

Well after reading all this talk about reinventing SDA's it got me motivated. I've got some free time next week so I'm going to try and reinvent the wheel. I'll let you guys how it turns out.

Get it? Turns out.

Can’t wait to hear what you think!
Turns out... lol.

verb wrote: »

As an alternative, what about Carver’s Sonic Holography amps? Plug and play, will work with any speakers. Not quite to the level of SDA, from what others have opined, but certainly less rework and iteration. Just a thought.

Never heard of those, I’ll give them a look later. Thanks!

ken brydson

mlistens03 wrote: »

KennethSwauger wrote: »

I applaud your willingness to experiment in the face of such woeful opinions. As a first step you might try removing your left and right speaker wires from your amp. Then take a single speaker (doesn't matter what kind of speaker, really) then connect a wire to your left positive terminal on your amp and a second wire to the right positive terminal on your amp. Then connect these two wires to your speaker, it doesn't matter which wire is connected to positive or negative. Now play some music and you'll hear the difference information coming from that speaker. It should sound like music coming from a distant location in your room.

@KennethSwauger , just making sure, you connect the positive terminals to two pieces of wire, then connect those wires to the positive and negative connectors on your speakers?

You forgot putting the positives on your tongue and standing in a bucket of water...

mlistens03

ken brydson wrote: »

mlistens03 wrote: »

KennethSwauger wrote: »

I applaud your willingness to experiment in the face of such woeful opinions. As a first step you might try removing your left and right speaker wires from your amp. Then take a single speaker (doesn't matter what kind of speaker, really) then connect a wire to your left positive terminal on your amp and a second wire to the right positive terminal on your amp. Then connect these two wires to your speaker, it doesn't matter which wire is connected to positive or negative. Now play some music and you'll hear the difference information coming from that speaker. It should sound like music coming from a distant location in your room.

@KennethSwauger , just making sure, you connect the positive terminals to two pieces of wire, then connect those wires to the positive and negative connectors on your speakers?

You forgot putting the positives on your tongue and standing in a bucket of water...

that sounds painful.

txcoastal1

TMI Ken, keep your playtime to yourself

mlistens03

txcoastal1 wrote: »

TMI Ken, keep your playtime to yourself

AGREED, 10,000 times.