Announcement

Collapse
No announcement yet.

Polk SDA reproduction?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Polk SDA reproduction?

    http://vr3mods.com/uploads/SDA_Handbook_2011_Rev3.pdf

    I've been reading about the Polk SDA speakers, from the golden age of stereo. They consisted of normal speakers which each had an extra mid and extra tweeter which contained, if I am not mistaken, an out of phase signal from the opposite speaker. The idea was that this cancellation would enhance the stereo effect.

    In practice I am sure that the crossovers were tweaked and altered so as not to simply create nulls all over the place. I have not seen a crossover schematic, much less any measurements.

    I've been thinking it would be fun to design a large classic 3 way with inexpensive drivers (think the carmody classix but BIG, maybe with a 12 and 2xdc160 per side?) and thought this might be an interesting avenue to explore.

    Has anyone here heard these speakers? Is there anything to be said for these larger 80s speakers?

  • #2
    Re: Polk SDA reproduction?

    My Polk Audio SDA 2BTL's are my main speakers. They are hot rodded with RDO 198 tweeters, Sonicraft caps and Mills resistors. I have also done some other mods found on the Polk Audio forum. I have yet to hear a pair of speakers I would rather own, even at 20+ times my total investment. They image very well and have a huge soundstage. You truly get to experience music. The design is entirely analog and passive. The dimensional drivers spaced the same distance as the average humans ears away from the stereo driver and cancel inter aural crosstalk to deliver a very realistic presentation. Bass in spades with a 12" passive radiator. The 2B's are the baby floor standers in the SDA series and do not even carry the SRS (Signature Reference Series) signature. Everyone should hear a pair of Polk Audio SDA's speakers.

    Comment


    • #3
      Re: Polk SDA reproduction?

      Originally posted by MLS View Post
      My Polk Audio SDA 2BTL's are my main speakers. They are hot rodded with RDO 198 tweeters, Sonicraft caps and Mills resistors. I have also done some other mods found on the Polk Audio forum. I have yet to hear a pair of speakers I would rather own, even at 20+ times my total investment. They image very well and have a huge soundstage. You truly get to experience music. The design is entirely analog and passive. The dimensional drivers spaced the same distance as the average humans ears away from the stereo driver and cancel inter aural crosstalk to deliver a very realistic presentation. Bass in spades with a 12" passive radiator. The 2B's are the baby floor standers in the SDA series and do not even carry the SRS (Signature Reference Series) signature. Everyone should hear a pair of Polk Audio SDA's speakers.
      The modern version of SDA is called Dolby Prologic. Where 5 speakers make the biggest widest soundstage you will ever experience.....if you know how to do it
      “Never ask people about your work.”
      ― Ayn Rand, The Fountainhead

      Comment


      • #4
        Re: Polk SDA reproduction?

        I had a set of SDA-1s. I really could not stand the way they screwed with the image. I sold them off.

        Comment


        • #5
          Re: Polk SDA reproduction?

          Google

          Polk Audio SDA White Papers.

          Specifically "Original SDA Technology"

          Comment


          • #6
            Re: Polk SDA reproduction?

            I've been reading them. I've been looking at the transfer functions of the tweeter array and it seems like they were just trying to limit vertical dispersion, presumably to match the woofer arrays. However, the tweeter spacing in the original SDAs was quite wide compared to what neo tweeters allow us to do now.

            I am wondering how much the effect depends on a large speaker. The role of the very wide baffle can't be completely discounted.

            Comment


            • #7
              Re: Polk SDA reproduction?

              the biggest problem with the SDA speakers was the issue with finding an amp that could handle the load. the speakers ate amps. even with high powered amps I never did think they sounded very good. there was always something just not right. polk pushed them really hard for about 7 years, but I do not think they really sold that many of them.
              craigk

              " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

              Comment


              • #8
                Re: Polk SDA reproduction?

                You can make you own decisions a 7 year run is pretty good I think.
                I have the big guys, they are the larger set of the two sets I have. They are 8 ohms and on 130 wpc just fine.
                I bet you didn't know there is an entire forum dedicated to them and Polk still supports them
                with replacement parts
                http://www.polkaudio.com/forums/foru...ntage-Speakers




                Originally posted by craigk View Post
                the biggest problem with the SDA speakers was the issue with finding an amp that could handle the load. the speakers ate amps. even with high powered amps I never did think they sounded very good. there was always something just not right. polk pushed them really hard for about 7 years, but I do not think they really sold that many of them.

                Comment


                • #9
                  Re: Polk SDA reproduction?

                  Originally posted by craigk View Post
                  the biggest problem with the SDA speakers was the issue with finding an amp that could handle the load. the speakers ate amps. even with high powered amps I never did think they sounded very good. there was always something just not right. polk pushed them really hard for about 7 years, but I do not think they really sold that many of them.
                  It's not difficult to find a common ground amplifier.
                  "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                  http://www.diy-ny.com/

                  Comment


                  • #10
                    Re: Polk SDA reproduction?

                    I had the smallest SDAs, the stand mount ones, and the imaging often was very impressive and similar to headphones - a backing vocal might be located 12 feet directly to your right, even though the wall was only 8 feet away. These effects were only with some material though, and otherwise the speakers didn't sound as nice as more expensive ones from JBL for instance.

                    It would be very interesting to hear a speaker using the SDA principle with better drivers and a crossover created with modern measuring/ design tools, but I imagine the measuring/ designing for that crossover would be tough!

                    Comment


                    • #11
                      Re: Polk SDA reproduction?

                      I had the pleasure of owning a pair of the very early Polk SDA-1. I really did enjoy them when they were properly set up. Even the lady liked the sound! Just not the fact that they were giant monsters in the living room. The soundstage really was fantastic.

                      Pics or it didn't happen: http://s1071.photobucket.com/user/Uz...y/Polk%20SDA-1

                      Comment


                      • #12
                        Re: Polk SDA reproduction?

                        yes, I know polk has an audio forum to support their products. here is a
                        link, http://www.polkaudio.com/forums/show...y-Matthew-Polk ,
                        to the letter from matthew polk stating that part of the reason they stopped the SDA line was do to amplifier issues, and the fact it was difficult for most people to properly set the speakers up at home and in the stores carrying the speakers. speakers are not suppose to sound like headphones, what headphones do to music is not an good representation of music. I do use headphones and like them, but I do not want my speakers sounding like headphones. I know there is a polk cult out there. I owned a pair of the monitor 5 junior speakers and enjoyed them. polk has put out a few pairs of good speakers, but when you have introduced over 100 speakers to the market, you have a few that sound good. I just have never been a fan of the SDA line, or most polk speakers.
                        Last edited by craigk; 06-27-2014, 08:07 PM.
                        craigk

                        " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

                        Comment


                        • #13
                          Re: Polk SDA reproduction?

                          Whoever states that SDAs sound like headphones would be incorrect. They don't image inside your head. This is coming from someone who's owned SDA 2Bs, SDA SRS2s, and headphones such as the Hifiman HE-6.
                          "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                          http://www.diy-ny.com/

                          Comment


                          • #14
                            Re: Polk SDA reproduction?

                            Imo, SDA's imaging is on the diffuse side compared to standard box speakers. Some models also sounded phasey to me.
                            "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

                            http://www.diy-ny.com/

                            Comment


                            • #15
                              Re: Polk SDA reproduction?

                              Originally posted by Face View Post
                              Imo, SDA's imaging is on the diffuse side compared to standard box speakers. Some models also sounded phasey to me.
                              I would agree with that, having restored and measured SDA 2Bs. In its time the SDA 2B was a very good speaker, but it fails a number of what would be considered critical modern design principles. In particular, for a pure mono signal above about 100Hz, for which the inner SDA drivers are silent, the mid-tweeter lobe at the 2500Hz crossover frequency is very narrow and the angle from the forward direction is large.
                              Action speaks louder than words but not nearly as often. -- Mark Twain

                              Comment

                              Working...
                              X