Good source for 6" port, and, is flare necessary?

Discussion in 'Archived Threads 2001-2004' started by Trenton McNeil, Jan 30, 2001.

  1. Trenton McNeil

    Trenton McNeil Second Unit

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    Punching my values into WinISD its looking like 2 4" ports
    or one single 6" port will work much better for my sonosub
    design...I'm having trouble locating a 6" flared port however,
    and was wondering if the flaring is really necessary with a
    6" port, or if I could just use basic PVC?
    Tempest driver
    10 ft^3
    24" diameter tube
    with a single 6" port 16 1/4" long, vent mach hits 0.12
    with two 4" ports 15 1/2" long, vent mach at 0.07
    single 4" port 6 1/4" long returns vent mach of 0.28!! that
    isn't gonna be acceptable...
    thoughts, ideas, HELP? I would like to track down the port
    before this weekend...
    ------------------
    [​IMG]
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  2. Marc_D

    Marc_D Extra

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  3. Chris Hoppe

    Chris Hoppe Stunt Coordinator

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    It looks like the two 4" ports would be a better idea anyways... Then you can use regular 4" PVC pipe. I think the vent mach on the single 6" is rather high.
    If you use double thick endcaps, you can make the hole on the outside piece the size of the inside diameter of the port. That way, the last 3/4" of your port will be made of wood, and you can use a 3/4" round router bit to flare your port.
    I did a similar design for an Eclipse 8815 with a similar volume, and I found that three 4" ports worked wonders!
    As long as you have the room for them, there are great gains to be has by keeping that port speed down as low as possible...
     
  4. Greg Monfort

    Greg Monfort Supporting Actor

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    >Punching my values into WinISD
    ====
    That's a mistake!
    ====
    >and was wondering if the flaring is really necessary with a
    6" port, or if I could just use basic PVC?
    ====
    Flaring isn't of any audible advantage until mach speed is > 5% (.05), or 56.5ft/sec (17.22m/sec), and since the flare rate needs to increase with increasing mach, you rapidly reach a point of diminishing returns, and still be able to fit the flare on the baffle.
    ====
    >Tempest driver
    10 ft^3
    24" diameter tube
    with a single 6" port 16 1/4" long, vent mach hits 0.12
    with two 4" ports 15 1/2" long, vent mach at 0.07
    ====
    Since two 4" have less cross sectional area than one 6", the 6" will have a slightly less vent mach, therefore WINISD is wrong.
    Either one flared 6", or three flared 4" would be my choice.
    ====
    >single 4" port 6 1/4" long returns vent mach of 0.28!! that
    isn't gonna be acceptable...
    ====
    It's more like 0.18, but still too high for me, even if flared.
    Ditch the program, as it's too inaccurate.
    GM
    ------------------
    Loud is beautiful, if it's clean
     
  5. Trenton McNeil

    Trenton McNeil Second Unit

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    WinISD too inaccurate? Okay....so what is more accurate?
    ?!
    ------------------
    [​IMG]
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  6. Jack Gilvey

    Jack Gilvey Producer

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    Trenton,
    LSPCad, which you can get over on the Adire site, is more accurate, and comes already loaded with Adire drivers' specs. It's not as easy to use,though. At least for me. Worth getting used to,though.
    ------------------
    http://content.communities.msn.com/i...&ID_Message=17
    "No,ma'am, I'm not the Pumpkin King. Lots of people make that mistake,though."
     
  7. Trenton McNeil

    Trenton McNeil Second Unit

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    Difficult to use is an understatement. [​IMG]
    Guess I'll break it back out and see what I can come up with.
     
  8. Chris Popovich

    Chris Popovich Stunt Coordinator

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    So back to those 6" port flares, do they work on standard PVC? If not, then what is used for the cylindrical port material itself?
    Thanks,
    Chris
     
  9. Jack Gilvey

    Jack Gilvey Producer

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  10. Trenton McNeil

    Trenton McNeil Second Unit

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    LPScad ain't so bad....I just ignore the room measurement stuff since my living room is so strangely shaped. [​IMG]
    Gonna goof around with a few more models before I put this thing together. Thanks to everyone for their input/ideas.
     
  11. Patrick Sun

    Patrick Sun Moderator
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    FYI, I located 6" wide PVC pipe, roughly 3/8" thick at Apex Supply in Atlanta (for those in the area). There are quite a few of them in the area, so get the phone book and call around (business white pages work well). It cost me about $18 for a 10 foot section (had it cut down in two 5 foot sections to haul it back home. The inner diameter was spot on at 6" wide, and its overall width was 6 11/16".
    Now, that 6" flared port flange kit from Tune Town intrigued me, but the website doesn't list prices for the flanges. Grr... If the price was reasonable, I'd order a flange pair, but just use one on the inside, and on the endcap just sand out a flare with the outer 3/4" MDF. But that's just me typing outloud.
    You'd think going from a 4" wide port to a 6" wide port would be a subtle change, but it's pretty substantial IMHO. Girth matters. [​IMG]
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  12. Trenton McNeil

    Trenton McNeil Second Unit

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    Pat, it looks like you really shouldn't have much problem
    using a 6" port with port noise even if used without the
    flared port opening, it might be purely academic at this
    point.
    I'm probably going to go with 2 4" ports, non-flared.
    ------------------
    [​IMG]
    I wish I had a dollar for every time I spent a dollar, because then, yahoo!,
    I'd have all my money back. -- Deep Thoughts, by Jack Handey
     
  13. Julian Data

    Julian Data Second Unit

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    Patrick,
    Unless you plan to extract every minute dB... talk tenths here, then go for the Flare port but if you don't listen "loudly", I wouldn't bother..
    Although, tenths add up to a dB [​IMG]
    Julian
     
  14. Patrick Sun

    Patrick Sun Moderator
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    "...if you don't listen 'loudly'"? Pshaw! [​IMG]
    BTW, I'm at work right now, being the voice of my company, I'm having to record the new name of the company for the auto attendant in the wee hours of the night. Yee-ha!
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  15. Andrew Pratt

    Andrew Pratt Producer

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    Trenton for my sub thats very similar to what you're building I ended up using three 4" ports. I wanted to make sure i was safe and I couldn't find 6" pipe that was viable to use (very costly compared to 4" stuff) At the volumes I've been able to stand I've never heard my ports but then I am not giving it goobs of power either.
    ------------------
    The Pratt Home Theater
     
  16. Neil Joseph

    Neil Joseph Lead Actor

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    Real Name:
    Neil Joseph
    I was faced with the same dilemma of using 2x4" or 1x6" ports. As I could not readily find 6" port, I decided to go with dual 4" with no flares (I am using 350W rms for power). Not only that, a 6" port would have to be longer and it would not fit in my enclosure, even with elbows.
    orangeman
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    Neil's H.T. Site
    (plus large selection of H.T.Links and movie images)
     

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