Creating the SDA effect ...?

sheathensemble

... using 4 RTI A5 towers?

Hi Guys, this my first post in the Polk forums.

I have a question for the SDA fanatics out there...

Would it be possible to create the SDA effect using 4 RTI A5 tower speakers?

What I am thinking is:
1) you run them off of the front Bi-amp ability that most modern day receivers have.
2)You would then place a pair of them in the typical stereo placement with typical hook up.
3) Then take the extra pair of RTI A5's and place them on the out side of the the first pair like this:

{pair2 left} {pair 1 left} tv/amps/whatever {pair 1 right} {pair 2 Right}

4)This pair you would then hook up to the opposite stereo channel (the left channel would run to the right and vice versa) and also flipping the positive and negative hook ups (flipping the polarity of the Second pair).

So my question is using proper placement in a standard room; would this create the SDA effect we all know and love?

I hope I have adequately expressed this question. I am aware that is probably a stupid question... but i couldn't find a similar post anywhere.

Cheers, Sheath

Toolfan66

audiocr381ve is that you????

heiney9

Nope, not even close. The placement of multiple pairs of speakers has nothing to do with the SDA. It's designed into the x-overs of two stand alone speakers. It also has nothing to do with "flipping polarity" at the speaker inputs or outputs.

H9

heiney9

toolforlifefan wrote: »

audiocr381ve is that you????

lmao :biggrin:

H9

heiney9

If you want to hear SDA's then the best thing to do is buy a pair of SDA's and run them in a 2 channel rig.

H9

audiocr381ve

TOOLFORLIFEFAN wrote: »

audiocr381ve is that you????

****.

audiocr381ve

heiney9 wrote: »

lmao :biggrin:

H9

Bigger ****.

sheathensemble

TOOLFORLIFEFAN wrote: »

audiocr381ve is that you????

Nope not me...

Just finished reading this: http://www.polkaudio.com/downloads/whitepapers/SDA_WhitePaper.pdf

and I guess I have the details of what they describe in the above confused. I was hoping that these same princibles could be applied externally of the speaker boxes.

Cheers, Sheath

sheathensemble

heiney9 wrote: »

Nope, not even close. The placement of speakers has nothing to do with the SDA. It's designed into the x-overs of two stand alone speakers. It also has nothing to do with "flipping polarity" at the speaker inputs or outputs.

H9

Just so there is no confusion... I was implying that the speakers would be set up right next to each other. The speakers on the right hand side would stand side by side and same on the left.

Cheers, Sheath

heiney9

sheathensemble wrote: »

Just so there is no confusion... I was implying that the speakers would be set up right next to each other. The speakers on the right hand side would stand side by side and same on the left.

Cheers, Sheath

I understood perfectly, nope not even close, not even remotely close. First of all the drivers would be too far apart and also the dimensional speakers in SDA's recieve a very low levele signal from the opposite channel in a very narrow frequency band. What you'd be trying to do is send a full level, full frequecny signal to a multiple driver speaker. Not even the same theory.

H9

sheathensemble

heiney9 wrote: »

I understood perfectly, nope not even close, not even remotely close. First of all the drivers would be too far apart and also the dimensional speakers in SDA's recieve a very low levele signal from the opposite channel in a very narrow frequency band. What you'd be trying to do is send a full level, full frequecny signal to a multiple driver speaker. Not even the same theory.

H9

The drivers would be at a similar distance to the SDA SRS 1.2's mids. As far as the levels are concerned they could be adjusted... you would just have to use an extended stereo setting as opposed to the bi-amped front setting to cover both pairs. The bandwidth on the hand would be a challenge. You could use external in-line crossovers to remedy this.

heiney9

sheathensemble wrote: »

Nope not me...

Just finished reading this: http://www.polkaudio.com/downloads/whitepapers/SDA_WhitePaper.pdf

and I guess I have the details of what they describe in the above confused. I was hoping that these same princibles could be applied externally of the speaker boxes.

Cheers, Sheath

Carver made a product in the 80's that sort of did this electronically. SDA's are much better, IMO.

Also the new generation of Polk Surround Bars do it electronically with DSP algorithms. Passively (non-electonically) there is no way to do it. The vintage SDA's (which are passive) sound much better than the SUrround bars but then they are designed for two entirely different purposes.

H9

Schurkey

I'd say it's the same theory, but extremely different implementation.

Considering the pitfalls of driver spacing, diffraction from the multiple speaker cabinets interfering with the propagation, bandwidth of the "SDA" signal, etc, your proposed implementation is far away from optimum.

First Guess: it's pretty much EXACTLY how the first SDA prototypes were implemented. The next day, Matt Himself figured out how to improve it, and never looked back.

Gavin.Wright

since the SDA effect is most simply put a passive means of cancelling crosstalk, why don't you go active and give ambiophonics a try. there is free software you can download to do this and the results are amazing! The advantage of ambiophonics is that the speakers are placed very close together (20 degrees or so) which lessens the extent of crosstalk, then the R.A.C.E (Recursive Ambiophonic Crosstalk Elimination) is applied which goes further than SDA's did in that the cancellation signal is cancelled by another cancellation signal, and so on...

Here's a link to the webpage with info http://www.ambiophonics.org/index.html

or you can download free software here...

http://www.ambiophonics.org/PCMac.html

I love my SDA's but have recently found that ambiophonics is just more effective, the center image is flawless, reverb fades away naturally and instruments are spread out nicely and easy to place within the soundfield.

Gavin.Wright

oh - and if you have 4 RTI A5's you could setup a 4 channel (panambiophonics) and get a full 360 degrees of sound!

sheathensemble

Gavin.Wright wrote: »

oh - and if you have 4 RTI A5's you could setup a 4 channel (panambiophonics) and get a full 360 degrees of sound!

HAHAH Love this! Thanks for the links in the previous post. I don't own 4, just a pair. The idea just came to me and I thought i should investigate it. Would i ever actually take that project on in the manner I have described? no... mostly I just wanted to get the topic aired as I couldn't find any relevant info online.

Thanks a bunch guys!

Cheers, Sheath

Toolfan66

audiocr381ve wrote: »

****.

Don't be mad cause I called you out..

dorokusai

Nope.

I've heard the Ambiophonics on a friends setup and I wouldn't call it better than SDA but its certainly different and imaging is very interesting to say the least.

I have the iPad application with a Jambox as described on the website. It's pretty neat.

audiocr381ve

TOOLFORLIFEFAN wrote: »

Don't be mad cause I called you out..

****.

FTGV

sheathensemble wrote: »

4)This pair you would then hook up to the opposite stereo channel (the left channel would run to the right and vice versa) and also flipping the positive and negative hook ups (flipping the polarity of the Second pair).

Well since the SDA signal consists of a R-L L- R you could try this as an experiment.Connect the positive terminals of the outside speakers as you would normally to the positive terminals of the amp.Then run a single piece of wire from the negative binding post of one of the outside speakers to the negative binding post on the other outside speaker with no connection to the amplifier.Connected as such the outside speakers will now be reproducing a R-L L-R signal.(The inside speakers would be connected as normal).However don't expect the full SDA effect because it is very dependant upon the optimization of the relative R-L L-R levels and precise positioning of the dimensional drivers.


A cautionary note,certain AVR 's may not like the load presented to it with this set up.

inspiredsports

audiocr381ve wrote: »

****.

Come on now. You have to admit that was pretty much spot-on and just damn funny

audiocr381ve

inspiredsports wrote: »

Come on now. You have to admit that was pretty much spot-on and just damn funny

Yea I was laughing my **** off, funniest thing in the world. :rolleyes:

sheathensemble

Keiko wrote: »

LMFAO!

Pretty lame sense of humor guys. There's reason to be calling ppl out for asking questions; This is a forum after all. The polk forum shouldn't be a place for you to see how many ppl you can insult at once. Take that **** back to the gearslutz forums.

Face

The newb has a point.