Precision Sound Products Flares

Discussion in 'Archived Threads 2001-2004' started by Dustin B, Mar 19, 2001.

  1. Dustin B

    Dustin B Producer

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    Does anyone know if the Precision Sound Products 4" flares will fit into the connectors for 4" thin wall PVC?
     
  2. Marv

    Marv Stunt Coordinator

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    Dustin I don't think they do. I will double check this tomorrow and get back to you if this is not the case.
    -Marv
     
  3. Dustin B

    Dustin B Producer

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    Thanks.
    Due to size constraints I think I've decided on what will be my best box and driver option. I'm planning on a 170L box (largest I can go) with an AVA250 and a Tempest (after bracing and everything else the box should be between 150-155L. The problem is that the port length I need is too long to fit straight within the height of the box. So the best solution I could think of would be to take two of the flares with the larger flanges with holes for mounting to surfaces. Mount one to the outside of the box and the other to a brace inside the box in a manner that would allow them to be connected by 4" PVC and two 45 degree elbows to my desired port length. But that hinges on being able to get two 4" flares with the larger flanges that will work with thin wall PVC and it's elbows and other connectors.
     
  4. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    I used the PE 4" flared port kit and it works fine in my application: Tempest sonosub.
     
  5. Patrick Sun

    Patrick Sun Moderator
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    Dustin, you should be able to get by with a 18"-19" long flared port (tunes to around 16Hz with a 6 ft^3 enclosure, stuffed with 44 ounces of polyfill - 50% fill). Surely you can fit this length of port in your box enclosure. You only need 1 port (cuts down on the length). Sure, going with 2 ports will cut down on port noise, and increase power handling, but with the AVA250, one flared port will suffice.
    I now avoid elbows and bends in the porting like the plaque.
    Both Hank and I have built ~6 ft^3 Tempest subs with 1 flared port, and were pleased with its performance. Mine's called Sunosub III.
    This will be a pretty "tight" sub, though its F3 will be 26Hz (maybe a little lower with room gain).
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  6. Dustin B

    Dustin B Producer

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    So you can see the problem. The outer dimensions I have choosen (as big as I can go). 24" W x 24" D x 22"H (plus 4" for legs. If I make it front firing I have 24" - 4.75" (4" of port clearance to a wall, and 3/4" for the depth of the wall the port isn't going through) which allows for up to a 19.25" port. If I make it down firing (which is what I had planned to do). I have 22" - 4.75" which allows for a 17.25" port. LspCAD tells me a 17hz tuning would require a 18.8" port and a 18hz tuning would require a 16.6" port (I've added 1" to those numbers to account for the flares). So I guess it just really depends on where I want to tune it. If I tune to just under 18hz or higher, I don't have a problem. If I want to tune to 17.5 hz or lower, I have a problem.
    I suppose I could just say screw it and make it with a 17" port which would tune it to 17.8hz and give me 4.25" clearance to the top of the box.
     
  7. Patrick Sun

    Patrick Sun Moderator
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    Use the 16.5" flared port (that's the total length of port since you only need a 15.5" long straight port) and stuff it with 44 ounces of polyfill for a tune of 17Hz and go with the front firing option. Problem solved.
    The stuffing lowers the tuning, so you can get away with a slightly shorter port.
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  8. Dustin B

    Dustin B Producer

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    Ok, I'm getting different numbers. Does LspCAD take the box volume you specify and then on its own remove the volume taken up by the port and driver, or do you have to do that manually. I'm not taking the port into account with the volume I enter into LspCAD but I am taking the driver into account.
     
  9. Patrick Sun

    Patrick Sun Moderator
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    I used your 155 liters of internal volume number. +/- 5 liters won't matter too much one way or another. FYI, I have another spreadsheet that allows me to see the volume changes when I move the port length around, and the length of sonotub, but this isn't really needed in this application.
    But either way, you're going into "paralysis by analysis" mode.
    Trust me, just build it with the 16.5" or 17" long flared port, and stuff it (with polyfill, that is). [​IMG]
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  10. Dustin B

    Dustin B Producer

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    I whole heartedly agree. That's pretty much the conclusion I've come to. Screw it, build the damn thing (and pray to god the $300 savings was worth not just buying a PW2200). The differences between a 17hz and 18hz tuning are minute, so why worry about it (and the port stuff on the 18hz tuning is so much easier to do).
    I assume the maximum length from the 4" ID flare kit from Adire is 18" (12" tube plus 6" of flare length)? So it should work just peachy. I'll make the tube 17" and the end result after lining all the walls of the box should be a tuning somewhere betwee 17.3 and 17.8hz.
     
  11. Marv

    Marv Stunt Coordinator

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    Dustin I took a 4" thin wall pvc "coupling" and my P.S. flared port end and the tube does fit into the coupler but very loosely (maybe 1/16" all around) to loose for me to consider it anyway. Hank is right, use the P.E. 4" flare end with thin wall pvc makes an almost perfect fit and cost much less but are a little harder to mount.
    Good Luck,
    -Marv G
     

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