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Theorized and tested: "Overdrive 10"...

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  • Wolf
    replied
    Apparently, the direction changed. There will be a 10" bandpass kit, but it will not be the Overdrive10/Kilauea. Another yet unseen model using the MAX10 will be coming very soon.
    I can tell them that you were awaiting a Kilauea kit though...
    Wolf

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  • Iridium
    replied
    Wolf Any idea when this will become a kit? I saw you comment on an audiosciencereview thread that it would be coming in kit form called Kilauea.

    https://www.audiosciencereview.com/f...drive10.30701/

    Leave a comment:


  • ani_101
    replied
    Originally posted by Wolf View Post
    Tune the PR to the Fb of the port in the bandpass model.

    You have to then model the active driver in the resulting vented bandpass volume with the PR as a PR model to check xmax on both the driver and PR. This will tell you if the PR can handle the load, and estimate mass requirements. Of note is keeping the PR volume small to raise its Fb to at or above the port Fb so that it can be tuned lower a smidge to measure and hit your target. Most PRs already have sufficient mass as they are tuned very low.

    I try to keep the alignment from becoming a loss, and not deviate from about +/-1dB in terms of gain. Take the diameter of the PR, and use it or just over as the H and W of cabinet, and then align depth to rear-most PR mass excursion plus about 1-1.5" to keep them from colliding under operation. This is my initial guess at PR volume when I model one. Drive the tuning up of the PR, and make the volume small for better coupling of the elements involved. Of course, the PR must allow the active driver to fit through it, or have a rear entrance for mounting. Double wall the active mount for collision reduction as well as strength, and recess driver into it.

    That help?
    Wolf
    it helped a bit. I'll try modelling with a driver and PR and see how far i can get...!

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  • Wolf
    replied
    Tune the PR to the Fb of the port in the bandpass model.

    You have to then model the active driver in the resulting vented bandpass volume with the PR as a PR model to check xmax on both the driver and PR. This will tell you if the PR can handle the load, and estimate mass requirements. Of note is keeping the PR volume small to raise its Fb to at or above the port Fb so that it can be tuned lower a smidge to measure and hit your target. Most PRs already have sufficient mass as they are tuned very low.

    I try to keep the alignment from becoming a loss, and not deviate from about +/-1dB in terms of gain. Take the diameter of the PR, and use it or just over as the H and W of cabinet, and then align depth to rear-most PR mass excursion plus about 1-1.5" to keep them from colliding under operation. This is my initial guess at PR volume when I model one. Drive the tuning up of the PR, and make the volume small for better coupling of the elements involved. Of course, the PR must allow the active driver to fit through it, or have a rear entrance for mounting. Double wall the active mount for collision reduction as well as strength, and recess driver into it.

    That help?
    Wolf

    Leave a comment:


  • ani_101
    replied
    Originally posted by Wolf View Post
    No- Unibox will not do PR-bandpasses. You model the BPST as it has, then model the PR box with the desired volume and PR and find your tuning mass. (I'm pretty sure it says on the graphic I posted that Unibox won't do it without doing 3 separate models. I put that at the bottom of the graphic) Then you make sure the PR will be fine at level for Xmax in its response.

    Later,
    Wolf
    Wolf

    HI Ben trying to understand the 3 step process. Band pass model gives two boxes (one with driver larger volume) and the one with the port (smaller volume). The bigger volume becomes the sealed box model - or rather plug in the sealed box volume as the larger box and take half the volume for the smaller box. Take this smaller volume and input into the PR model and add the PR parameters. What are we aiming for the PR mass tuning? The lower F3 from the band pass model or something that looks good for the PR mass model

    Also, modelling the driver with the PR for normal PR modelling is required or desired to find out which PR is a good fit or find s PR with the small box volume that hits the desired F3 with the weight the PR can handle.

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  • Ironman129
    replied
    Originally posted by Wolf View Post
    Any progress, @Ironman?
    Later,
    Wolf
    Unfortunately I am out of the country for the next week. I was hoping to get it assembled before I left but that did not happen. :(

    Scott

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  • Wolf
    replied
    Any progress, @Ironman?
    Later,
    Wolf

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  • Wolf
    replied
    Thanks, Wogg!
    Wolf

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  • wogg
    replied
    I love this build... small sub with low 20's extension and decent max SPL. Only trade off is crossing to mains at 60Hz or so, which isn't really a trade off if you have decent mains to pair.

    I need to play with band passes more, my prior attempts at modeling were in BB6, which ended up trying my patience with trial and error. Difficult when you don't quite understand what you're doing.

    Leave a comment:


  • Wolf
    replied
    I don't think you understand how the bandpass works. It isn't due to using the PR at all, but to just using a bandpass. A bandpass acoustically filters both ends of the bandwidth the woofer in the design plays. As such, you can have a wider bandwidth and lose sensitivity, or you can have narrower bandwidth and focus on one-note output potential. The points of rolloff affect output and bandwidth. In my alignment, I only gained 0.1dB over the use of the driver normally. This means I got the maximum bandwidth with no loss of sensitivity- in terms of acoustic response. The boost adds the low-end extension where it was needed.

    Later,
    Wolf

    Leave a comment:


  • xmax
    replied
    The +.1 is from the larger surface area of the PR? Although it seems (the design) would provide some useful "compression"
    in a very literal way.
    Last edited by xmax; 08-14-2018, 10:51 AM.

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  • Wolf
    replied
    In the graphic it says gain +0.1dB, so no loss in output.
    Wolf

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  • xmax
    replied
    Sorry if you mentioned it somewhere and I missed it, but how much loss did you
    get with sensitivity? Obviously not enough to outweigh the benefits but I'm
    still curious.

    Leave a comment:


  • bullittstang
    replied
    Great project Wolf! I am huge fan of the small but very capable subwoofer design and this has nailed that for sure.

    Leave a comment:


  • Wolf
    replied
    I suppose I could, but I haven't yet. I could likely take an indoor nearfield facing up as well in the middle of my living room. I have 10' ceilings.

    I don't have a reason to doubt Unibox though...

    Later,
    Wolf

    Leave a comment:

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