SDA 1 and SDA 1B (why did polk change tweeter position??)

tophatjohnny
tophatjohnny Posts: 4,182
edited November 2012 in Vintage Speakers
Seeing these pop up all over the place and looking at the SDA1's the tweets are side by side on top and the SDA 1B's tweets are stacked on top of each other. Why was this change made and was it for the better?? Anyone know??
"if it's not fun, it's not worth it & remember folks, "It's All About The Music"!!
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Post edited by tophatjohnny on
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  • agfrost
    agfrost Posts: 2,428
    edited November 2012
    Original SDAs had a dimensional tweeter, not just dimensional mid driver(s). This was phased out in newer models as most of the SDA "magic" occurred in the frequencies covered by the mid drivers and there were some less-than-desirable sonic aspects with the dimensional tweeter.

    Some (perhaps all?) of the SDAs with vertically arranged tweeters had them fed differently from the crossover, so they didn't all output identically. See if you can read the SDA handbook that DarqueKnight authored that VR3 has uploaded on his site. I'm by no means a guru of all things SDA, and you'll get the straight dope in that handbook.
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • tophatjohnny
    tophatjohnny Posts: 4,182
    edited November 2012
    agfrost wrote: »
    Original SDAs had a dimensional tweeter, and there were some less-than-desirable sonic aspects with the dimensional tweeter.


    The SDA 2.3's have the same up and down tweeter placement, so "less than desirable" puzzles me a tad?? Really looking to see if anyone knows why the change was made from side my side placement of the tweeters to the up and down placement. That's all.
    "if it's not fun, it's not worth it & remember folks, "It's All About The Music"!!
    *****************************
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  • agfrost
    agfrost Posts: 2,428
    edited November 2012
    Side by side tweeters (as the original SDA 1's and CRS) had the lesser performance. 2.3's were not the "original" SDAs, and were getting close to the best SDAs Polk made. The last (TL) series had their best tweeters and perhaps improved cabinets.

    Really, any of you that know more than me are free to jump in here any time... :lol:

    Here, get your read on: LINKAGE
    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Oppo BDP-93 * Modded Adcom GDA-600 DAC * Rythmik F8 (x2)
    Micro Seiki DQ-50 * Hagerman Cornet 2 Phono * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
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  • bigaltx24
    bigaltx24 Posts: 141
    edited November 2012
    IIRC the stacked tweeters act as a line source with the bottom one handling the lower high end and the top one handling the upper high end.
    Denon PMA-900V
    Linn Axis with Grado Red
    Cambridge Azur 650C
    Polk SDA-1BTL
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  • Schurkey
    Schurkey Posts: 2,101
    edited November 2012
    bigaltx24 wrote: »
    IIRC the stacked tweeters act as a line source with the bottom one handling the lower high end and the top one handling the upper high end.
    Top tweeter is full-treble-range rolled off only at the low-cut crossover frequency. Lower tweeter is more bandwidth-limited, same low cut-off as the upper, but also with a high-frequency rolloff. Progressive point source (PPS) using two tweeters, while the SRS 2.3 has a three-tweeter PPS, and the SRS, 1.2, and 1.2TL use a four-tweeter PPS array.

    Removing the SDA tweeter is arguably "THE" single-biggest improvement among the various SDA generations. Everything made AFTER the SDA tweeter was removed is clearly a step above everything made with an SDA tweeter. Perhaps some folks will disagree.
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  • tophatjohnny
    tophatjohnny Posts: 4,182
    edited November 2012
    agfrost wrote: »
    Side by side tweeters (as the original SDA 1's and CRS) had the lesser performance. 2.3's were not the "original" SDAs, and were getting close to the best SDAs Polk made. The last (TL) series had their best tweeters and perhaps improved cabinets.

    Really, any of you that know more than me are free to jump in here any time... :lol:

    Here, get your read on: LINKAGE

    Great download and thank you for the straight forward answer I could make sense of! Also thanks to "bigaltx24" for slapping it down for me! :wink:
    "if it's not fun, it's not worth it & remember folks, "It's All About The Music"!!
    *****************************
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  • F1nut
    F1nut Posts: 50,561
    edited November 2012
    Schurkey's description is more accurate, they are a progessive point source.
    Removing the SDA tweeter is arguably "THE" single-biggest improvement among the various SDA generations. Everything made AFTER the SDA tweeter was removed is clearly a step above everything made with an SDA tweeter.

    Agreed.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • tophatjohnny
    tophatjohnny Posts: 4,182
    edited November 2012
    F1nut wrote: »
    Schurkey's description is more accurate, they are a progessive point source.



    .
    Maybe if you understand tongues??:razz:
    "if it's not fun, it's not worth it & remember folks, "It's All About The Music"!!
    *****************************
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