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Polks new Flagship Line, The Legend Series: Reintroduces SDA Technology

TitaniumTroy

Well-Known Member
#1
http://www.theabsolutesound.com/articles/polk-audio-introduces-new-flagship-speaker-line/
Leading the flagship loudspeaker line is the company’s L800 “True Stereo” floor-standing speaker featuring next generation Stereo Dimensional Array (SDA-PRO) technology, the first SDA speaker introduced in over 20 years and the only speakers in the world to maintain full stereo separation from the source to the listener’s ears. The result is the most lifelike imaging, smooth spectral response and deep, tight bass normally found in speakers several times the cost.

I never really got the full effect of the SDA back in the day for some reason, guess I will have to try a Magnolia Design Center at a Best Buy in Chicago. To see if this new version works any for better for me.
 

Flint

"Do you know who I am?"
Superstar
#3
http://www.theabsolutesound.com/articles/polk-audio-introduces-new-flagship-speaker-line/
Leading the flagship loudspeaker line is the company’s L800 “True Stereo” floor-standing speaker featuring next generation Stereo Dimensional Array (SDA-PRO) technology, the first SDA speaker introduced in over 20 years and the only speakers in the world to maintain full stereo separation from the source to the listener’s ears. The result is the most lifelike imaging, smooth spectral response and deep, tight bass normally found in speakers several times the cost.

I never really got the full effect of the SDA back in the day for some reason, guess I will have to try a Magnolia Design Center at a Best Buy in Chicago. To see if this new version works any for better for me.
I read the patent on this, and they really did their research. They mimic the cross fade transform of the human face and ears facing opposite directions with the reverse phase onto, something they failed to do in the original SDA implementation.
 
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TitaniumTroy

Well-Known Member
#4
I read the patent on this, and they really did their research. They mimic the cross fade transform of the human face and ears facing opposite directions with the reverse phase onto, something they failed to do in the original SDS implementation.
Cool, since I am all about imaging/soundstage. I'll really be looking forward to giving this a listening session. Flint what about comb filtering, from the dual midrange's or do they have a way compensating for that problem.
 

Flint

"Do you know who I am?"
Superstar
#5
Cool, since I am all about imaging/soundstage. I'll really be looking forward to giving this a listening session. Flint what about comb filtering, from the dual midrange's or do they have a way compensating for that problem.
That's not how it works.

The outside midrange and tweeter are being fed the signal from the opposite channel and are attenuated and with inverted polarity. The result is the right ear primarilu gets the right signal and an inverted left signal and an a reduce SPL and EQed to reflect the crosstalk from the left speaker. The left speaker gets the opposite. The result is the sound more closely reflects the sound of headphones where the left and right signals are not shared between ears. The two midrange units in each speaker are reproducing different channels, so mono comb-filtering won't occur in a traditional sense. However, if a signal is mono, like the vocal track, things get strange. This is where acoustics will mess with things and make it so more crosstalk occurs than with headphones. .
 

malsackj

Well-Known Member
#6
one thing they did not address in the white paper is the first reflection points and the acoustics of the room. The setup is assumed to work in Near Field Monitors and the room acoustics not being addressed.
 

malsackj

Well-Known Member
#7
I have found that the mono center image to be very good. But this was using the home built version that does not have the signal attenuation for the out of phase opposite side. My crossover was around 200 to 260 hz for the bass module to the 4 inch drivers I used as midrange.
 

Flint

"Do you know who I am?"
Superstar
#8
one thing they did not address in the white paper is the first reflection points and the acoustics of the room. The setup is assumed to work in Near Field Monitors and the room acoustics not being addressed.
In fact, projecting an out of phase signal from about 6 to 10 feet away from the original source signal reduces some of the room reflection issues by causing significantly more cancellations than reinforcements. That said, placement will be very critical to the enjoyment of these speakers.
 

MatthewB

Grandmaster Pimp Daddy
Famous
#9
My best friends father has the original SDA towers (big enough to be buried in) they come with an anchor bolt so you can secure it to the wall so they don't tip over. These speakers are 40 years old and I bet have less than 100 hours of use in 40 years. He just never uses them. I've asked him multiple times in the past 30 years if I could buy them off of him but he refuses to sell them.
 

Randy

Well-Known Member
Famous
#11
There could very well be an emotional attachment to the speakers. Maybe he rarely gets the opportunity to dedicate the time to listening but when he does it is his version of audio nirvana.

Maybe he looks at them as a status symbol and cant bare the thought of selling them.

Maybe he just likes them and doesn't want to sell them.
 

Randy

Well-Known Member
Famous
#12
I had one of my very first eye opening audio experiences with Polk SDA 1.2's if my memory serves me correctly I think 1.2 was the model number, anyway but they were gigantic like Matt explained and powered by some crazy Carver and Harmon Kardon setup with like 2000 watts per channel.

Listened to them and was blown away, then my buddy took me across town and I listened to a pair of Klipschorns fed by tube preamp and tube amps (biamped I think) with less than 50 watts per side going into it and I was absolutely blown away.

I preferred the Klipsch setup and my buddy said "Don't be fooled by numbers, they are not as important as the salesman would have you believe."
 
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