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Tweeter Leaking Air

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  • twelve-thousand-parrots
    started a topic Tweeter Leaking Air

    Tweeter Leaking Air

    I'm designing a set of smallish desktops and I've run into a problem. My tweeters (Dayton Audio DSN25F-4) are leaking air through the body of the tweeter itself. I've tested several strategic applications of foam tape, but it has almost no effect at all. The only thing that has helped is putting foam tape on the body of the tweeter itself, isolating the fabric dome from the rest of the driver, and covering that with a piece of MDF. Note that the woofer and the tweeter share the same internal enclosure.

    I've attached a video demonstrating the test described above.

    Does anyone have suggestions about how to solve this problem? Do I need to build a separate enclosure for the tweeter? If so, I'll probably have to rebuild the whole enclosure. :(

  • twelve-thousand-parrots
    replied
    Originally posted by mattp View Post
    FWIW...

    If this is a leaky tweeter it appears to be a one-off problem. Possibly a lack of glue between the plastic and metal frames on the tweeter itself. I do not see how air could get between the dome and plastic flange on these.

    I performed a test with two different sealed enclosures here in the lab, one with the drivers separated (not overlapped) and one mounted the way you show in the video. With random drivers pulled from stock I could not replicate a leak on either enclosure. I played 10-60 Hz tones at around 9 volts. It is also not a problem we have come across before, so this appears to be a random uncommon one-time issue.

    If something like this occurs I encourage you to contact our customer service first at 800-338-0531. If it is a defective product we are very good about getting it replaced quickly.
    Matt, I appreciate your efforts to test this on your end. I agree that it's probably a one-off problem, and I've been very happy with everything else I've purchased from Dayton. I suspect this issue is process-related since both the tweeters I received exhibited this issue. I still haven't decided if I'm going to contact customer service since it may be more of a hassle and time sink than my current fix.

    Leave a comment:


  • twelve-thousand-parrots
    replied
    Originally posted by GTPlus View Post
    silly question, but are you by chance running the tweeter too low? What frequency is your HP filter? Seems implausible for chuffing like in the video if you have the back completely sealed.
    I'm crossing it at about 3 kHz, which is about double the tweeter's Fs, so that shouldn't be an issue. To be clear, the chuffing in the video was prior to sealing the back's with silicone. The chuffing is now all but inaudible.

    Leave a comment:


  • mattp
    replied
    FWIW...

    If this is a leaky tweeter it appears to be a one-off problem. Possibly a lack of glue between the plastic and metal frames on the tweeter itself. I do not see how air could get between the dome and plastic flange on these.

    I performed a test with two different sealed enclosures here in the lab, one with the drivers separated (not overlapped) and one mounted the way you show in the video. With random drivers pulled from stock I could not replicate a leak on either enclosure. I played 10-60 Hz tones at around 9 volts. It is also not a problem we have come across before, so this appears to be a random uncommon one-time issue.

    If something like this occurs I encourage you to contact our customer service first at 800-338-0531. If it is a defective product we are very good about getting it replaced quickly.

    Leave a comment:


  • turn2
    replied
    Originally posted by twelve-thousand-parrots View Post

    The tweeter is flush mounted. The mounting scheme is similar to that of Paul Carmody's Speedsters, where the tweeter is flush mounted and the woofer is surface mounted and slightly overlaps the tweeter flange. There would be a massive air gap if both drivers were surface mounted and overlapping, and that is not what I've done. I have foam gasket tape under the woofer flange that seals the intersection between the woofer and tweeter, and although this could be optimized further, it is not the primary source of the air leak.

    I ended up covering the entire back of both tweeters in silicone caulk and this solved the problem. Thanks for everyone's help. I will post pictures of the final solution including the tweeter treatment and foam gasket tape soon.
    Okay, maybe what I was seeing standing proud of the baffle was the mounting screw and not the rim of the tweeter. My bad. Carry on.

    Leave a comment:


  • GTPlus
    replied
    silly question, but are you by chance running the tweeter too low? What frequency is your HP filter? Seems implausible for chuffing like in the video if you have the back completely sealed.

    Leave a comment:


  • twelve-thousand-parrots
    replied
    Originally posted by AEIOU View Post

    Good observation, the overlap could well indeed be the source of his consternation. I find it very hard to believe that someone is incapable of finding and sealing a simple leak. The likelihood that the tweeter was defective is plausible, but highly unlikely.
    Yikes, that seemed a little aggressive.

    Leave a comment:


  • twelve-thousand-parrots
    replied
    Originally posted by turn2 View Post
    It appears from the pics that your tweeter is not flush mounted, and that your woofer laps over the flange of the tweeter. Is this correct?
    The tweeter is flush mounted. The mounting scheme is similar to that of Paul Carmody's Speedsters, where the tweeter is flush mounted and the woofer is surface mounted and slightly overlaps the tweeter flange. There would be a massive air gap if both drivers were surface mounted and overlapping, and that is not what I've done. I have foam gasket tape under the woofer flange that seals the intersection between the woofer and tweeter, and although this could be optimized further, it is not the primary source of the air leak.

    I ended up covering the entire back of both tweeters in silicone caulk and this solved the problem. Thanks for everyone's help. I will post pictures of the final solution including the tweeter treatment and foam gasket tape soon.

    Leave a comment:


  • turn2
    replied
    I watched this again in the exploded video version and I guarantee you that the woofer is not seated against the baffle and is leaking air where it overlaps the not-flush-mounted tweeter. Flush mount the tweeter; problem solved.
    Last edited by turn2; 01-23-2019, 03:46 PM. Reason: Solution added.

    Leave a comment:


  • durwood
    replied
    When I look at the tweeter gasket that is included with it by zooming in, it seems like air could easily leak from the screw holes since the gasket cutout is open towards the tweeter, but it is unclear if he tested that. Maybe the block of wood was blocking the sound from the screw holes. Picture of how you sealed the tweeter with silicone? Some silly putty over the screw holes might help rule that out.

    Leave a comment:


  • AEIOU
    replied
    Originally posted by turn2 View Post
    It appears from the pics that your tweeter is not flush mounted, and that your woofer laps over the flange of the tweeter. Is this correct?
    Good observation, the overlap could well indeed be the source of his consternation. I find it very hard to believe that someone is incapable of finding and sealing a simple leak. The likelihood that the tweeter was defective is plausible, but highly unlikely.

    Leave a comment:


  • turn2
    replied
    It appears from the pics that your tweeter is not flush mounted, and that your woofer laps over the flange of the tweeter. Is this correct?

    Leave a comment:


  • twelve-thousand-parrots
    replied
    Originally posted by Wolf View Post
    Do you have a gasket under the frame to seal it? Is it sealed at the woofer cutout?
    Wolf
    I do have a gasket under the tweeter frame and the woofer frame, and I combined several different orientations of gasketing without success.

    I did just test the tweeter-covered-in-silicone method and that worked, the tradeoff being that the tweeter is now covered in silicone ;)

    Leave a comment:


  • Wolf
    replied
    Do you have a gasket under the frame to seal it? Is it sealed at the woofer cutout?
    Wolf

    Leave a comment:


  • twelve-thousand-parrots
    replied
    No dice on the separate enclosure + silicone idea. I've completely covered the back of the tweeter with silicone and am waiting for it to cure. If that doesn't work, I guess I return the tweeters and go back to the drawing board. That would be a shame because I really wanted to use those tweeters...

    Leave a comment:

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