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

Lerjebrink
Lerjebrink Posts: 3
in DIY, Mods & Tweaks
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.
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Comments

  • pitdogg2
    pitdogg2 Posts: 27,333
    OH BOY !!
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  • F1nut
    F1nut Posts: 52,008
    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."

    President of Club Polk

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  • heiney9
    heiney9 Posts: 25,510
    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!
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  • heiney9
    heiney9 Posts: 25,510
    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!
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  • heiney9
    heiney9 Posts: 25,510
    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!
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  • xschop
    xschop Posts: 5,413
    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.
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  • F1nut
    F1nut Posts: 52,008
    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

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  • heiney9
    heiney9 Posts: 25,510
    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!
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  • F1nut
    F1nut Posts: 52,008
    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

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  • Lerjebrink
    Lerjebrink Posts: 3

    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.
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  • Lerjebrink
    Lerjebrink Posts: 3
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    dewe2dxhmc0a.jpeg
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  • pitdogg2
    pitdogg2 Posts: 27,333
    F1nut wrote: »
    Found them.
    lne2j8s9ds77.jpg

    Ben?
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  • heiney9
    heiney9 Posts: 25,510
    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!
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  • 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.
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  • 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

    Polk 7B main speakers, std. mods+ (1979, orig owner)
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  • pitdogg2
    pitdogg2 Posts: 27,333
    Gardenstater wrote: »
    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.
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  • xschop
    xschop Posts: 5,413
    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.
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  • 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.
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