/ Register

Geo - Remember The Pvc ?

Discussion in 'General Car Audio Discussions' started by Mr Cabinetry, Feb 28, 2004.

Page 1 of 2
  1. Mr Cabinetry

    Mr Cabinetry Full Member

    Geo,

    I had posted the question over in CAF about building an enclosure with PVC.

    Well, it finally got installed yesterday in the SSR.

    That enclosure hit rock solid and hard.

    No Flex, no distortion, no ill effects what so ever, structurally dead.

    It didn't even need any polyfill.

    After actually seeing the enclosure installed in the vehicle, I could of definitely got alittle more volume out of it.

    I'm going back down to the shop today and taking my digital camera with me.

    Another first, I will admit that for the past couple of years I always wondered about fabricating an enclosure using PVC.

    Also, I believe the shop and SSR are going to get a write up in one of the Car Audio Rags.


    Phil
     
    Mr Cabinetry, Feb 28, 2004
    #1
  2. sandt38

    sandt38 Full Member

    [​IMG]



    These are also made out of PVC. They have a sub of similar design that uses it as well... amazingly these sewage pipe creations cost $8800 retail.

    Oh and Phil, YGPM :p
     
    sandt38, Feb 28, 2004
    #2
  3. hobbes26

    hobbes26 Full Member

    (psst - Phil, ya gotta fix the link in your WWW)



    How long can the pipe be before the woofer can't make use of the volume anymore?
     
    hobbes26, Feb 28, 2004
    #3
  4. flawlesskid

    flawlesskid Full Member

    That looks pretty damn pimp seth! I'd like to fugg around with something like that..
     
    flawlesskid, Feb 28, 2004
    #4
  5. Honest Bob

    Honest Bob Full Member

    Need pictures! :D
     
    Honest Bob, Feb 28, 2004
    #5
  6. geolemon

    geolemon Full Member

    Sounds cool!

    PVC may have better damping properties.. I believe it's less dense than other plastics, like Acrylic, Lexan... which are in turn less dense than things like steel, glass, etc.

    But, you'll note with the $8800 wonder-tubes (lol) that they have special "damping panels"...
    Of course, in the high-end audio marketplace (ie. those looking to spend $8800), things like that are likely simply an expected 'given'. :p
     
    geolemon, Feb 28, 2004
    #6
  7. Mr Cabinetry

    Mr Cabinetry Full Member

    :oops: It's fixed!!!!
     
    Mr Cabinetry, Feb 29, 2004
    #7
  8. Mr Cabinetry

    Mr Cabinetry Full Member

    Mr Cabinetry, Feb 29, 2004
    #8
  9. sandt38

    sandt38 Full Member

    If we get to dense we wind up with resonance issues though, wouldn't you expect?

    As far as the special "polymer dampening panels", I'll wager they are also called eggcrate foam :p . I have a distibutor who handles Vince Christian and I assure you... $8800 is a HUGE markup, (but retail price and all, what can I say...) so I am forced to assume it is really nothing all that spectacular.

    Cort,

    It is cool. Chris and I were discussing these the other day in referance to a line array for in home. The other thing that stands out in my mind is the lack of a reflective baffel. I am forced to wonder how much of a differance this makes in pure reproduction. It is obvious that reflective cancellation is tremendously reduced, but I am not really sure how much is really accomplished or gained by this.
     
    sandt38, Feb 29, 2004
    #9
  10. sandt38

    sandt38 Full Member

    Wow. When you said PVC I assumed you were using tubular PVC for the enclosure, not flat panel (beautiful enclosure by the way). Was tthe PVC requested or is it something you just wanted to play with? I am interested in why it was chosen over a material that we all know works well that costs less :blink:
     
    sandt38, Feb 29, 2004
    #10
  11. The_spacemonkey

    The_spacemonkey Full Member

    I would think there will be a huge decrease in weight. That could definately be a driving factor.

    If that works out well phil, its a great Idea for those people that dont want all that weight of MDF.


    Oh.. and as density goes up, generally resonances go down. As stiffness goes up, resonances raise in frequency(and vise versa)


    hehehe... Im not sure why, but this emoticon amuses me :bag:
     
    The_spacemonkey, Feb 29, 2004
    #11
  12. Feandil

    Feandil Full Member

    Does it remind you of how you like your women? :blink: :blink:













    <_<
     
    Feandil, Feb 29, 2004
    #12
  13. Mr Cabinetry

    Mr Cabinetry Full Member

    I used PVC material for a few reasons <_<

    1. Given the design of the enclosure as shown in the link I provided, the size of the enclosure is small, roughly 22 1/4" w x 9" h x 9" d.

    2. The design is modeled from the molded piece that fit into the area of original install
    in the SSR. I wish I took a pic of that when the car's interior was ripped apart.

    3. The enclosure volume had to be able to fit 2 JL 8w3v2's sealed, using MDF would not of provided the volume needed.

    4. I've been toying around with the idea to build an enclosure out of PVC for at least a few years, I just never had the opportunity to build one.

    5. I spec'd the PVC for this enclosure, I figured that if I applied the same principals of fabrication as to cutting parts and assembly, using the proper bonding materials to assemble it, the enclosure would be if not more structurally sound and neutrally denses than Fiberglass, Plus, the assembly would take less time than fabrication with fiberglass.

    6. In the area where it is to be installed, there was a great likelyhood of the enclosure be subjected to moisture. PVC = Waterproof

    Granted, 1/4" PVC does weigh considerably less than 3/4" MDF, so there would be a great deal of weight difference. The cost however would make the any enclosure considerably more expensive given the material costs, time and labor involved.

    Personally, I don't think anyone would want to pay for such an enclosure.
     
    Mr Cabinetry, Feb 29, 2004
    #13
  14. hobbes26

    hobbes26 Full Member

    Having a shape such as a pipe will cause there to be resonances - one of the
    reasons why a lot of speakers are built as a trapezoid or with walls not parallel.

    I guess that's why there is damping inside the tube, but that's the tradeoff, I guess
    if you don't want a large flat baffle in the plane of the speaker...

    Granted, the resonances in the tube are much more selective (there's fewer of
    them) so I guess if you concentrate on damping only those certain frequencies,
    you can get good results...



    edit: just thinking more - there will be resonance peaks at every k*L = n*pi
    where k is the wavenumber.... I wonder how difficult it would be to control these...
     
    hobbes26, Feb 29, 2004
    #14
  15. The_Ancient

    The_Ancient Full Member

    What is the Cost over MDF Ratio???

    This could be intresting, I have never Seen a Box made form PVC in this fasion before, and I might be in the market for a new truck box soon ;)
     
    The_Ancient, Feb 29, 2004
    #15
  16. The_spacemonkey

    The_spacemonkey Full Member

    Hey Phil.... what did you use to bond the PVC together?
     
    The_spacemonkey, Feb 29, 2004
    #16
  17. Mr Cabinetry

    Mr Cabinetry Full Member

    Michael,

    The piece of PVC Sheet was 48 x 48 x 1/4 at $ 40.00, if I had bought a full sheet of 1/4" PVC at roughly $ 80.00 vs 3/4" MDF Sheet at $ 20.00, well you can see the price difference already just in the material.

    Also, given the way I calculate the cost of MDF enclosures, there is no way I can use that same calculation to determine the cost of a similar enclosure fabricated with PVC.

    There is more time and labor involved here. Not to mention that each and every part has to be cut and joined precisely in order to provide the maximum contact between the parts being assembled. There is very little room for error.

    The enclosure as pictured took over 15 hours to fabricate - cutting and fitting the parts and then assembling all the those parts.

    Basically, a customer wanting an enclosure made out of PVC would be paying between $25.00 to $40.00 per hour - Labor plus Materials. :jawdrop:

    It would not be a cheap enclosure, but it would be d@mn near bulletproof as to structural integrity given the bracing requirements, but it would be lighter than an MDF enclosure and waterproof.

    That's why I said " Given what it would cost to build an enclosure out of PVC, no one would be willing to pay what it would cost. "

    Of course though, depending on what subwoofers were to be used in such an enclosure might or would require thicker PVC which would mean higher costs and increased weight given the actual design and specifications of the enclosure.

    Working with PVC is definitely not a DYI project if one does not have all the skill, tools and material required. The cost factor is way out there... :no:
     
    Mr Cabinetry, Mar 1, 2004
    #17
  18. The_Ancient

    The_Ancient Full Member

    Never Say No One

    I buy alot of things on the "WOW THAT IS NEAT" factor

    I have a whole garage full of crap I never use for that reason :lol:
     
    The_Ancient, Mar 1, 2004
    #18
  19. Mr Cabinetry

    Mr Cabinetry Full Member

    Space,

    I used a product from FastCap, it a two part adheasive system, bonds just about everything under the sun and it ain't cheap.

    This is the Kit :

    http://www.fastcap.com/prod.asp?page=2p10kit

    This is the individual breakdown of the products:

    http://www.fastcap.com/parts3.asp
     
    Mr Cabinetry, Mar 1, 2004
    #19
  20. Mr Cabinetry

    Mr Cabinetry Full Member

    Michael,

    Well, if you want to be the first kid on the block with a totally fabricated PVC enclosure, besides the owner of the SSR that I built the enclosure for, who am I to say otherwise ;)
     
    Mr Cabinetry, Mar 1, 2004
    #20
Page 1 of 2