Getting the full SDA Effect from Polk L800 Speakers

[tjcinnamon]

Yesh. I would contact Matthew. He is a room accoustics expert.


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Update

Method: I moved everything around in my room. Removed the diffusers, pushed the TV back, removed the bass traps, moved the speakers forward so nothing was in front of them at all, heck, removed all of the couch cushions... I experimented with moving the room treatments behind the TV, behind the speakers, next to the speakers, everything I could think of. Also, a substantial amount of time went into unplugging SDA and testing without. Also, I moved my seat toward and away from the speakers to test the soundstage changes. Then slowly added items back.

Source Material: I used that Cars Stereo Track and Dire Straights Private Investigation test tracks with the Eagles Hotel California Live and a Yosi Horikawa track called Bubbles.

Results: Ultimately I could get the sound stage to be approx 1' to 3' to the right or the left of the speaker vs SDA off. Meaning it's working in some capacity but the speakers are still localizable. However, my expectations could be too high relative to my first impression. That said despite the left/right expanded sound stage it was substantially more 3D. It was a "between the speakers" with SDA and didn't have a lot of the Z axis (between me and the speakers). I don't like using terms like that but that's what the effect offers.

Remaining items: order some additional amps off Crutchfield for testing. I think the Stereo store where it hit crazy good was using a Parasound or a Rotel (I requested one of them). I'm going to ask them to see which one it was. I doubt it's the amp but it's a super easy test. Outright remove the TV from in between (even if it's pushed back). Granted the TV has to be there in the end but it will give me insight. I may even try a dedicated pre-amp for academic purposes.

Questions: The outer speaker is the one that is the SDA, correct (just making sure I have them correct)? Does 1' to 3' seem normal or a touch weak for soundstage?

 

[Golfx]

Wow you’ve done some heavy lifting. Regarding the SDA, yes outer ones cancel. Did you listen to recommended “wandering” test album yet? It’s last track, early in, where the shoes are crunching gravel, was so expansive it sounded very briefly as if it was coming from over my rt shoulder from seemingly my surround rear. The first track bubbles sounded like it was outside my walls. You really should contact Matthew Poes.


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[Golfx]

Wow you’ve done some heavy lifting. Regarding the SDA, yes outer ones cancel. Did you listen to recommended “wandering” test album yet? It’s last track, early in, where the shoes are crunching gravel, was so expansive it sounded very briefly as if it was coming from over my rt shoulder from seemingly my surround rear. The first track bubbles sounded like it was outside my walls. You really should contact Matthew Poes.


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[Golfx]

Edit. I see you did listen to bubbles. Try the last track too.

 

[tjcinnamon]

Wow you’ve done some heavy lifting. Regarding the SDA, yes outer ones cancel. Did you listen to recommended “wandering” test album yet? It’s last track, early in, where the shoes are crunching gravel, was so expansive it sounded very briefly as if it was coming from over my rt shoulder from seemingly my surround rear. The first track bubbles sounded like it was outside my walls. You really should contact Matthew Poes.


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I plan to. We've been in email correspondance. I'm going to run my final checks and then reach out to Matt.

 

[tjcinnamon]

also, irrespective of the SDA effect not hitting it's full potential, the speakers sound fantastic and I'm coming from some Paradigms Prestige which were no slouch. So overall, I'm happy but given their size and cost, I'd like to maximize them.

 

[Golfx]

They are awesome speakers. Congratulations again.


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[tjcinnamon]

Wow you’ve done some heavy lifting. Regarding the SDA, yes outer ones cancel. Did you listen to recommended “wandering” test album yet? It’s last track, early in, where the shoes are crunching gravel, was so expansive it sounded very briefly as if it was coming from over my rt shoulder from seemingly my surround rear. The first track bubbles sounded like it was outside my walls. You really should contact Matthew Poes.


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Just sent payment and I look forward to meeting with him. We've narrowed it that it's likely the distance from my seated position and the rear wall.

 

[Golfx]

Uhoh time to move houses.


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[tjcinnamon]

Uhoh time to move houses.


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not quite yet! I've been working with Matt Poes from Poes Accoustics on a paid consult and we have some good direction at this point. Now I just need to find the time to implement. It's been really fun because I was an REW amateur before and I'm getting some cool pointers to look at.

With SDA it's a lot of trial and error because it won't show up on the measurements from the perspective of, "is it working"

 

[Golfx]

Excellent!


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[Michal Zigo]

Thanks Matthew for another informative review (seen also the youtube version). Though I`ve seen rather good polar response graphs, would you recommend them for home theatre "simulation" where only front L+R channels (and maybe SW at max) can be deployed considering your expertise and in-person-experience? In other terms, I comply with recommended spatial setup of the speakers (40m2 living room connected with about the same dining+kitchen rooms) . Or even, do you think for the stereo listening + movie watching is Arendal 1723 Tower a better option? Thanks

 

[Matthew J Poes]

Thanks Matthew for another informative review (seen also the youtube version). Though I`ve seen rather good polar response graphs, would you recommend them for home theatre "simulation" where only front L+R channels (and maybe SW at max) can be deployed considering your expertise and in-person-experience? In other terms, I comply with recommended spatial setup of the speakers (40m2 living room connected with about the same dining+kitchen rooms) . Or even, do you think for the stereo listening + movie watching is Arendal 1723 Tower a better option? Thanks

It’s going to be two very different experiences. The Polk has good measured response with SDA. As with most XTC filters, the cancelation causes a coloration. Polk claims it’s the lowest it’s ever been, but it was still audible to me. I noted it as causing a harshness to the treble.

compared to the Arendal it will be less neutral by a small amount (but unplugging the SDA cable would make them similar). The Arendal will play louder. The Polk will have a very different soundstage/imaging.

I will be doing some experiments with the BACCH software on this issue of XTC and surround. I had expected that the Polks would make great surround speakers. What I have found is that the envelopment doesn’t blend as well with the center as I hoped. The envelopment with only two speakers for LR and surrounds was good, but hit or miss due to how the soundtrack was encoded. I have the best version of the BACCH software and I will use a faculty it has for mixing down HOA in order to mix down ATMOS to binaural and see what happens. I’ll try it with Polk and the digital filters (which have way more cancelation and no timbre shift). That would let me answer your question better. Right now I don’t know what was working and what wasn’t. ABing full surround systems isn’t so easy.

I think the Arendal is the better speaker of the two. The Polk will always have that magic imaging that I found so compelling. It took my a while to wrap my head around what was missing that they did. The Polk SDA filter does a very poor job of XTC compared to the best digital filters, but it still works and even a tiny amount creates the effect. Stereo systems are totally devoid of spatial effects. There is no sense of envelopment. Any spaciousness is a function of the room. Surround can recreate spatial effects but it can’t do so the same way we would hear in real life. So it’s still a poor facsimile. XTC allows you to hear exactly as you would in real life. The biggest thing lacking in all surround systems is proximity. That is the sense is closeness or distance you get between you and a sound object. A surround system is incapable of realistically recreating the perception of someone walking up to your ear and whispering in it. There are key spatial cues we need to recognize that and surround or stereo cannot reproduce them. Polk can recreate that. Not well, not nearly as good as the best possible, but it’s there enough to be noticeable. For someone like me who is really into the perception of realism, this is a compelling case for the Polks.

something I have found with numerous buyers of the SDA’s who contacted me for help, they all had good speaker locations but a lousy room. XTC is trying to beam binaural signals to the left and right ears with no distortions. It can’t be corrupted. The SDA tech cancels a small amount of the crossover distortion, the crosstalk from L-R and R-L. It can’t cancel or correct reflections. Even the digital versions cannot. If your couch will be against a wall, the effect won’t work much at all. If the speakers are too close to sidewalks, it won’t work. Reflections are an enemy of XTC.

 

[Michal Zigo]

It’s going to be two very different experiences. The Polk has good measured response with SDA. As with most XTC filters, the cancelation causes a coloration. Polk claims it’s the lowest it’s ever been, but it was still audible to me. I noted it as causing a harshness to the treble.

compared to the Arendal it will be less neutral by a small amount (but unplugging the SDA cable would make them similar). The Arendal will play louder. The Polk will have a very different soundstage/imaging.

I will be doing some experiments with the BACCH software on this issue of XTC and surround. I had expected that the Polks would make great surround speakers. What I have found is that the envelopment doesn’t blend as well with the center as I hoped. The envelopment with only two speakers for LR and surrounds was good, but hit or miss due to how the soundtrack was encoded. I have the best version of the BACCH software and I will use a faculty it has for mixing down HOA in order to mix down ATMOS to binaural and see what happens. I’ll try it with Polk and the digital filters (which have way more cancelation and no timbre shift). That would let me answer your question better. Right now I don’t know what was working and what wasn’t. ABing full surround systems isn’t so easy.

I think the Arendal is the better speaker of the two. The Polk will always have that magic imaging that I found so compelling. It took my a while to wrap my head around what was missing that they did. The Polk SDA filter does a very poor job of XTC compared to the best digital filters, but it still works and even a tiny amount creates the effect. Stereo systems are totally devoid of spatial effects. There is no sense of envelopment. Any spaciousness is a function of the room. Surround can recreate spatial effects but it can’t do so the same way we would hear in real life. So it’s still a poor facsimile. XTC allows you to hear exactly as you would in real life. The biggest thing lacking in all surround systems is proximity. That is the sense is closeness or distance you get between you and a sound object. A surround system is incapable of realistically recreating the perception of someone walking up to your ear and whispering in it. There are key spatial cues we need to recognize that and surround or stereo cannot reproduce them. Polk can recreate that. Not well, not nearly as good as the best possible, but it’s there enough to be noticeable. For someone like me who is really into the perception of realism, this is a compelling case for the Polks.

something I have found with numerous buyers of the SDA’s who contacted me for help, they all had good speaker locations but a lousy room. XTC is trying to beam binaural signals to the left and right ears with no distortions. It can’t be corrupted. The SDA tech cancels a small amount of the crossover distortion, the crosstalk from L-R and R-L. It can’t cancel or correct reflections. Even the digital versions cannot. If your couch will be against a wall, the effect won’t work much at all. If the speakers are too close to sidewalks, it won’t work. Reflections are an enemy of XTC.

Thanks a lot, that was a quick response! Yes, I`m very interested in the BACCH experiments and their quantification you are going to make - I`ll be eagerly waiting for the results.

Now, perhaps I owe you some explanation what I was aiming at with my original question:
I do currently have a deviation of Mr. Lee`s NS15 speakers as a product of local fanclub now endulging in perfecting the waveguide to be used in such designs. Those speakers are fine and soon they would get 1 sub to begin with (I know the benefits of at least 2 in acoustic environment). However the acoustic conditions are not ideal ones as I have a lot of floor-to-ceiling windows and not one ac. treatment (besides the carpet in front of TV where our cat is often resting, you can call it the bouncy house) When the press releases and your reviews of the SDA based Polk L800 hit me I thought that the speaker fits perfectly to the dispositions I have (keeping the cca 0,8 speakers/me ratio; close to wall; no near sidewall; don`t want to use the living room as HT with other channels though would like to enhance the space effect when watching on the cinema screen). So to conclude it, I have to borrow the L800s into my house, compare& measure...and then let painful dilema begin .

 

[Golfx]

Be sure to use Matthew’s recommended “wandering” album by Yosi Horikawa mentioned in Matthew’s written review. I had the L800s with an Anthem AB amp and it literally sounded as if the sounds were coming from outside my windows and walls. Awesome experience.


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[Matthew J Poes]

Thanks a lot, that was a quick response! Yes, I`m very interested in the BACCH experiments and their quantification you are going to make - I`ll be eagerly waiting for the results.

Now, perhaps I owe you some explanation what I was aiming at with my original question:
I do currently have a deviation of Mr. Lee`s NS15 speakers as a product of local fanclub now endulging in perfecting the waveguide to be used in such designs. Those speakers are fine and soon they would get 1 sub to begin with (I know the benefits of at least 2 in acoustic environment). However the acoustic conditions are not ideal ones as I have a lot of floor-to-ceiling windows and not one ac. treatment (besides the carpet in front of TV where our cat is often resting, you can call it the bouncy house) When the press releases and your reviews of the SDA based Polk L800 hit me I thought that the speaker fits perfectly to the dispositions I have (keeping the cca 0,8 speakers/me ratio; close to wall; no near sidewall; don`t want to use the living room as HT with other channels though would like to enhance the space effect when watching on the cinema screen). So to conclude it, I have to borrow the L800s into my house, compare& measure...and then let painful dilema begin .

Message me privately if you want. May have an option for you.

 

[kevintomb]

I have always loved Polk speakers from way back since the early 80s.

But never could get past the feeling that the SDA effect was mostly/all a gimmick.

The whole idea is based on an idea that makes no sense if you really think about it.

The "White Paper" that explains how it all works, makes one HUGE wrong assumption. The assumption is that recordings are made with a Left and Right microphone, arranged the way our ears are on our head.

Problem is, except for SOME classical and binaural stuff, 99% of rock, pop and so on, are NOT recorded in this manner at all, but are simply studio creations with musical sound placement all done electronically and the placement of sounds is determined by a normal stereo Left/right pair of speakers.

 

[Golfx]

I didn’t get just that interpretation from their explanation. There are other skeptics in the above string which matthew did a good job countering.

 

[kevintomb]

I didn’t get just that interpretation from their explanation. There are other skeptics in the above string which matthew did a good job countering.

I have to disagree respectfully. No matter how the SDA effect is explained, it does not take into account that the vast majority of recordings are not made in the manner in which SDA would be beneficial to use. I will gladly read something explaining it better, but from all I have read, it is a great idea in a way and frankly I like the effect on some recordings for sure, but it simply is not needed on most recordings and is redundant.

 

[Golfx]

Ah, well I was referring to your use of the wording gimmick and makes no sense at all. It did work quite well for me and I agree that it is more apparent on binaural recordings.