Path lenght of Tempest bass horn?

Discussion in 'Home Theater Projects' started by Jani_K, Dec 3, 2004.

  1. Jani_K

    Jani_K Auditioning

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    Hi all!

    I've read this forum quite a bit, since this is almost only place where i've seen some discussion/threads about Tempest bass horn.

    I'm currently building such bins (4 of them.. for PA use, with different drivers).

    They should be ready within maybe few weeks and i would like to know how much should i delay top bins. (Of course that would depend on top bins but i think path length would be nice starting point to calcule 'near' delay-value) As You can see, i'm not really experienced when it comes to horn speakers. I figured out that anyway it's easier to start with Tempests than LABsubs.. (and a lot cheaper.. [​IMG])

    Has anyone here any experience with these horns? (hmm.. should i call for DanWiggins? [​IMG])

    Regards,
    Jani
     
  2. Greg Monfort

    Greg Monfort Supporting Actor

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    Since you're building them, you can measure the inner and outer wall pathlengths, then: sqrt(L1*L2). This doesn't include the mouth's end correction or any boundary effects though, so the acoustic pathlength will be somewhat lower in frequency. Also, it varies with frequency at some point, so if you're XOing high enough to be out of the horn's passband, i.e. it's in direct radiator mode, it may be even longer due to reflections.

    Bottom line, ask DW since he will have the unfolded design parameters, and I imagine actual measured ones for various XO frequencies.

    GM
     
  3. Jani_K

    Jani_K Auditioning

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    Thanks very much!

    I think general info is always better than already 'chewed'! [​IMG]

    I feel that i'm a lot wiser now.. (Though now that You mentioned how to calculate it, i think i should have known it myself.. [​IMG] Basic math! But somehow in the middle of such a 'big' DIY project i've gotten confused several times already)

    I think the final alignment should be measured with smaart, etc. (if i remember correctly there is a functional demo version out..) but path length is the 'coarse' value to start with..

    -Jani-
     
  4. DanWiggins

    DanWiggins Second Unit

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    Jani,

    We measured a "delay" of 4.3 msec through the horn, which corresponds to about 58 inches of path length.

    Dan Wiggins
    Adire Audio
     

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