SDA 2A no bass in left speaker

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acscience
acscience Posts: 5
in Troubleshooting
Hey all,

I have a pair of SDA 2A speakers that were previously working great. After a move, now I’m not getting anything from the bass driver in the left speaker.

I’m not too speaker-savvy so after opening it up and not seeing any glaring issues like disconnected wires I’m pretty much at a loss. Any help would be super appreciated, I’m assuming I’d need a new driver?

I am using the distance cable also, not sure if that matters. Doesn’t change anything when I unplug it.

Here’s what it looks like behind the bass radiator:

ae20lkvys3uy.jpeg
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  • F1nut
    F1nut Posts: 52,406
    edited January 2025
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    Does the driver in question move freely?

    BTW, it's called the SDA cable, not distance cable. What you called the bass radiator is called a passive radiator.
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  • treitz3
    treitz3 Posts: 20,360
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    Your crossover should be mounted. It appears as if it is completely free from any structure whatsoever.

    Could you possibly add some additional photos from within the speaker itself, if it isn't too much trouble?

    BTW, please allow me to offer you a very warm welcome to Club Polk.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • Unknown
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  • F1nut
    F1nut Posts: 52,406
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    treitz3 wrote: »
    Your crossover should be mounted. It appears as if it is completely free from any structure whatsoever.

    Not sure what you're looking at, but it is mounted.

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  • acscience
    acscience Posts: 5
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    Thanks so much everyone for the help and the correction on terminology! The driver is mounted to the back, I took it off to take a better look but it’s been reattached in the picture. I will grab more pictures today and see if I can slightly move the driver in and out or see if it’s seized.

    Also just to educate me a bit, what is the purpose of the SDA cable?

    Thanks again, be back shortly.
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  • acscience
    acscience Posts: 5
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    pitdogg2 wrote: »
    One board XO, might be SDA 2b. SDA 2a was a two board XO.
    I'm in the camp that a magnet has slipped as well. What are the driver numbers? MW6510, MW6511, MW6503?
    Also was there any polyfil that was right behind the passive or is it still only behind the active drivers?

    I didn’t see anything behind the passive at all. What would I be looking for? All I saw was some styrofoam inside the passive.
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  • F1nut
    F1nut Posts: 52,406
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    acscience wrote: »
    Thanks so much everyone for the help and the correction on terminology! The driver is mounted to the back, I took it off to take a better look but it’s been reattached in the picture. I will grab more pictures today and see if I can slightly move the driver in and out or see if it’s seized.

    Also just to educate me a bit, what is the purpose of the SDA cable?

    Thanks again, be back shortly.

    There should be no driver mounted on the back!

    The SDA cable enables the SDA driver(s) to function. SDA speakers have stereo and SDA drivers.
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  • F1nut
    F1nut Posts: 52,406
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    acscience wrote: »
    pitdogg2 wrote: »
    One board XO, might be SDA 2b. SDA 2a was a two board XO.
    I'm in the camp that a magnet has slipped as well. What are the driver numbers? MW6510, MW6511, MW6503?
    Also was there any polyfil that was right behind the passive or is it still only behind the active drivers?

    I didn’t see anything behind the passive at all. What would I be looking for? All I saw was some styrofoam inside the passive.

    All the polyfill should be above the PR, so you're good.
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  • invalid
    invalid Posts: 1,559
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    pitdogg2 wrote: »
    One board XO, might be SDA 2b. SDA 2a was a two board XO.

    My sda 2a crossover doesn't look like the one the OP has pictured, if I remember correctly there are 2 round circuit boards, one mounted to the binding post plate and one mounted to the big inductor.
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  • acscience
    acscience Posts: 5
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    invalid wrote: »
    pitdogg2 wrote: »
    One board XO, might be SDA 2b. SDA 2a was a two board XO.

    My sda 2a crossover doesn't look like the one the OP has pictured, if I remember correctly there are 2 round circuit boards, one mounted to the binding post plate and one mounted to the big inductor.

    Does this mean that I have the 2B? I see a date of 1989 on the stickers found on the components.

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  • Unknown
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    edited January 2025
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  • acscience
    acscience Posts: 5
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    pitdogg2 wrote: »
    acscience wrote: »
    invalid wrote: »
    pitdogg2 wrote: »
    One board XO, might be SDA 2b. SDA 2a was a two board XO.

    My sda 2a crossover doesn't look like the one the OP has pictured, if I remember correctly there are 2 round circuit boards, one mounted to the binding post plate and one mounted to the big inductor.

    Does this mean that I have the 2B? I see a date of 1989 on the stickers found on the components.

    If you would give us the midwoofer numbers we would be able to tell you.
    Is the SDA cable pin/ blade or dual blades or is the SDA socket in the cup or outside the binding post cup on the back of the cabinet?

    I will get some more pictures posted today. SDA is pin/blade. Pin on top, single blade on bottom.
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  • skipshot12
    skipshot12 Posts: 2,156
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    First thing I’d check is all the connectors to the board. Unplug and plug back in.
    Would be a good time to check all connections.
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  • invalid
    invalid Posts: 1,559
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    You can TL all single board crossover models



    You can actually TL the sda 2a with the dual boards, but you can't use an isolation transformer.




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  • skipshot12
    skipshot12 Posts: 2,156
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    Toolfan66 wrote: »
    skipshot12 wrote: »
    First thing I’d check is all the connectors to the board. Unplug and plug back in.
    Would be a good time to check all connections.

    While he has or had the passive off, yes worth checking, but the first thing on his list is checking those drivers.

    Oh yes, especially after a recent move.
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