Mini models of the SDA SRS. i need help with crossovers.

Hi everyone! I am building miniature versions of my SDA SRS speakers. I would like to have some pro help in my project. I have ordered mid and tweeters, and i am going to design the crossovers now.

I don't even know where to start. Every calculator is for 2-way systems, but i want to include SDA in the speakers. I know that it is impossible to get it exactly right with these components, but i want to try to get it as close as i can.

Down below are some images of the original wiring scheme with all the component values, and also the new speakers/tweeters for my mini build, along with pictures of the original speaker/tweeter specs.
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Please message me or answer here in the discussion.

Comments

  • pitdogg2
    pitdogg2 Posts: 27,335
  • F1nut
    F1nut Posts: 52,009
    If you want smaller SDA speakers find a pair of SDA CRS+. Otherwise, you are wasting time and money.
    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."


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  • heiney9
    heiney9 Posts: 25,513
    edited April 7
    The front baffle of full sized SDA's play a part, not sure how'd you even calculate that. I'm sure you could make min-replica's after much time, expense and effort. But they will not sound anything...........anything like larger SDA's. They might not even sound good playing 2ch music.

    What size passives are you using and how are you calculating the volume of the cabinet? How do you know your mini driver choices will even excite the PR enough to get the freq response nec? That's one of hundreds of questions.........

    The drivers that create the SDA have to mathematically be positioned a certain distance apart. How wide is the front baffle on your mini's? Thats why CRS's are on their sides.

    It's a waste of time and money

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • heiney9
    heiney9 Posts: 25,513
    edited April 7
    The old SDA's are an acoustic experience. It can't be scaled smaller easily because certain physical parameters and ratios of those parameters are needed for the process to work effectively. SDA- CRS's are about the smallest you can go physically.

    If this were an electronic issue it would still be difficult, but perhaps with enough knowledge, they could be scaled down to somewhat work.

    Polk makes sound bars with an electronic algorithm (along with some physical attributes) that simulates the acoustics of SDA. Honestly my soundbar is like that, and it's not very convincing.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • heiney9
    heiney9 Posts: 25,513
    I had to go back and look to see if this was posted on April 1st. :p

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • xschop
    xschop Posts: 5,415
    As long as the centers of the MW drivers are the listener's ear-to-ear width, the IACC will be achieved.

    Would be fun to see a full build thread here.

    Welcome to the gauntlet.
    Don't take experimental gene therapies from known eugenicists.
  • F1nut
    F1nut Posts: 52,009
    I recall a member built a homemade pair of very large SDA speakers years ago with MWxxxx drivers properly spaced. By all of the many accounts they sounded like crap.
    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

  • heiney9
    heiney9 Posts: 25,513
    edited April 7
    He's not using MW drivers and to me "mini" means smaller than CRS's.

    I guess the OP needs to define what 'Mini" means. He's showing 2" speakers

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • F1nut
    F1nut Posts: 52,009
    Found them.
    lne2j8s9ds77.jpg
    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

  • Lerjebrink
    Lerjebrink Posts: 4

    So…

    Just a disclaimer. This build is just an homage to my real pair. I know nothing will be exactly right, because of MANY factors. But i kinda want to try to get it as close as i can, just for fun, just for the nerdiness.

    My first thought was a usual 2-way crossover, and to scrap the SDA totally. But… then i thought. Why not make it as close as possible?

    So.
    Im taking every measurement and multiplying by 0.35. This results in 2 inch drivers instead of 6.5 inch. And the passive radiator in the bottom will be a 5.25 inch.

    I think i will buy one seperate 8 inch Sub to carry the heavy hz, so that won’t be a problem.

    In mm it will be 577.5mm in height, 192.5 in width, and 115.5mm in depth. Mostly made of MDF, and the top and bottom in pure oak.

    The SDA cable will be a gold plated 3.5mm AUX just for simplicity.

    I know i make trouble for myself by buying no-name speakers off amazon. But i don’t want the homage minispeakers to cost more than the original speakers… lol.
    i think with the right crossover, i can make it kind of playable. At least i want to try!

    I Will keep you guys updated. As soon as i get speakers and tweeters in the mail I Will start with the cabinets.
  • pitdogg2
    pitdogg2 Posts: 27,335
    F1nut wrote: »
    Found them.
    lne2j8s9ds77.jpg

    Ben?
  • heiney9
    heiney9 Posts: 25,513
    Yep, Ben.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • Emlyn
    Emlyn Posts: 4,827
    Lerjebrink wrote: »
    dewe2dxhmc0a.jpeg

    About the best that could come of that small homage design would be to have a pair of functional standard stereo speakers with unnecessary drivers that look like SDAs but aren't. Stereo Dimensional Arrays don't work that small even for a head the size of a house cat's.

    No harm in experimenting though.
  • Gardenstater
    Gardenstater Posts: 4,804
    I think for the IACC to work the stereo and dimensional speakers center to center distance should be at least the distance between your ears. You will have only 3.6 in. Not trying to be negative but it is something to consider.
    George / NJ

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  • pitdogg2
    pitdogg2 Posts: 27,335
    I think for the IACC to work the stereo and dimensional speakers center to center distance should be at least the distance between your ears.
    Correct! ^^^^^

    I do agree with @Emlyn, no harm in creating a mini set of stereo speakers similar to the big boys. Creating a mini SDA is not going to happen.
  • xschop
    xschop Posts: 5,415
    edited April 7
    If you can get the center to center distance of MWs 145-170mm from each other, IACC will work assuming your head is positioned in proportion to the SDA setup diagram.
    Don't take experimental gene therapies from known eugenicists.
  • msg
    msg Posts: 10,473
    Nothing technical to add, but I like the enthusiasm, curiosity, and creativity driving this idea, and that it's coming out of your immense appreciation for your SDA SRS, even if it winds up on Facebook Marketplace in the end.
    I disabled signatures.
  • motorstereo
    motorstereo Posts: 2,369
    Paying "homage" to them would be better spent by modding those sda's. A good start would be tweeters, perhaps aluminum tweeter bezels, bh5, dynamat and VR3 crossovers if you're actually serious. Of course better electronics would also pay a nice "homage" and yield a nice return but hey it's your time and money.
    Better yet apply those soon to be wasted resources to a pair of 1.2tls with a dreadnaught.
  • Lerjebrink
    Lerjebrink Posts: 4
    You guys have a point. If the SDA effect depends on the distance, it is game over for the sda idea.

    My first thought now is to instead do a 2-way. But i wonder.. should i do a real 2way or should i try to make the tweeters seperate like the original? And if i do that, should i do the same for the mids? Or should i just aim for a regular 2-way
  • xschop
    xschop Posts: 5,415
    Even at @100mm distance (as you have in your tech drawing). The IACC will be there, just diminished, soundstage not even as wide as a set of 2B's.

    If you do build them, you may find the highs sounding better than the SL2000's.
    Don't take experimental gene therapies from known eugenicists.
  • VR3
    VR3 Posts: 29,553
    On my desktop I ran a separate integrated amp and threw some drivers beside the monitors and setup a quick and dirty sda arrangement and it honestly added to the stereo image in that environment and you could control the volume of the sda drivers thru the integrated.

    The further out you place the sda drivers the wider and more diffuse the stage becomes
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • audioluvr
    audioluvr Posts: 5,989
    You should have posted this on April 1st. It would have made more sense. You should also build a mini Matthew Polk in a white lab coat that you can stand next to them. I have to admit though, you do have good taste in brandy.
    Lerjebrink wrote: »
    dewe2dxhmc0a.jpeg

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  • heiney9
    heiney9 Posts: 25,513
    Lerjebrink wrote: »
    You guys have a point. If the SDA effect depends on the distance, it is game over for the sda idea.

    My first thought now is to instead do a 2-way. But i wonder.. should i do a real 2way or should i try to make the tweeters seperate like the original? And if i do that, should i do the same for the mids? Or should i just aim for a regular 2-way

    Remember, the multi tweeters in SDA's are progressive point source, so you'd have to figure that out. Running multiple tweets at full output would kill any imaging and sound stage in a recording.

    Side by side drivers are evil too, lots of combing effect. That's why the 10B's have issues that the 5B and 7B don't have. SDA gets away with it because they aren't all playing the same freq at the same output level.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Puritan Audio PSM136 Pwr Condtioner & Classic PC's | Legend L600 | Roon Nucleus 1 w/LPS - Tubes add soul!
  • F1nut
    F1nut Posts: 52,009
    soundstage not even as wide as a set of 2B's.
    You mean not 20+ feet wide like I got from mine.
    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

  • xschop
    xschop Posts: 5,415
    F1nut wrote: »
    soundstage not even as wide as a set of 2B's.
    You mean not 20+ feet wide like I got from mine.

    Agree, he'd get like 10, maybe 12 ft wide soundstage. But at near-field/desktop, could be incredible.

    SDA-10B's also throw the same width soundstage as 2B's FYI.
    Don't take experimental gene therapies from known eugenicists.