Want to do DIY sub but have worries.

Discussion in 'Home Theater Projects' started by Adam, Feb 24, 2006.

  1. Adam

    Adam Stunt Coordinator

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    I have been wanting to build a sub for a log time, but I am worried about building the box.

    I do not have a lot of wood working tools and it seems that it would be a big investment to build one sub.

    What is the minimum tools I would need to build my own box.
    For example, table saw, hole cutting jig, large clamps (how many), router, etc.?

    Also,

    Where is the best DIY sub forum these days. There isn't alot of action around here these days.

    Thanks,
    Adam
     
  2. Dave Poehlman

    Dave Poehlman Producer

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    I've gotten away with just a hand jig saw... to cut the driver hole. Oh yeah.. and a drill to predrill screw holes... oh.. and wood glue. [​IMG]

    First figure out the size of your box and what size MDF cuts you'll need. Then go to your local Home Depot or other warehouse home improvement center when they're not too busy and ask them to make the cuts for you.

    The sign says they can only be accurate to 1/4" or something like that... but, if you catch them when they're not busy and find someone helpful, they'll cut 'em nice for you. And, they don't usually charge me for extra cuts even if they're supposed to.

    If you're concerned about internal bracing... here's a cheap (and easy!) solution using large diameter dowels:


    [​IMG]
     
  3. Brent_S

    Brent_S Second Unit

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    Started with a $27 Black&Decker jigsaw, electric drill, and a 4'x8' sheet of mdf many many moons ago. It can be done, but probably not the prettiest.

    One design that would require minimum tools is a Dayton DVC15 or Quattro15 in roughly 6 ft^3 tuned to 20hz. If you can find them in stock, HD carries panel/project boards of mdf in 16"x48"x.75" sizes. Four of those are your walls. A fifth panel can create the top/bottoms which could be rough cut with a jig or circular saw, or flush trimmed with a router. The left overs can be turned into bracing. About as easy as it gets without buying a prebuilt cabinet, if you can tolerate the 16"x17.5"x49.5" external dimensions.

    The more clamps the better. I would use at least 8 for the idea above...but I like to glue all four sides of my box at once and then add the top/bottom.

    You could build a sonotube with just a drill, jig saw, router and circle jig of some sort. Assuming you like the aesthetics.

    I would guess that Parts Express "Tech Talk" may currently be the most active DIY site. Madisound has their own forums as well, but I hardly ever visit so don't know enough to say yay/nay. Go through the archives here and you find lots of good info and links as well.

    The process should go something like this:
    1) define your performance goals (low frequency extension & spl output)
    2) how much room space can you devote to a subwoofer cabinet
    3) what's your budget for project
    4) download modelling s/w (WinISD, UniBox, PEBox)
    5) load up driver parameters from Parts Express, Madisound, OAudio, etc. until you find something that meets 1-3
    6) compromise 1 and/or 2 and/or 3 to reach 5
    7) have fun or give up and call SVS

    wbs
     
  4. Adam

    Adam Stunt Coordinator

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    Thanks for your replies. The only 16" by 48" MDF I have seen at Home Depot was bull nosed for shelves or step treads. THey do have larger 24"x24" and 24"x48" pieces, but that is larger than the box I would want to make. Also, how much would 8 clamps cost? The ones at HD are around $14 each for 24". Thats $116 just in clamps.

    I have had HD cut a sheet of MDF for me to make shelves, cheaper than buying smaller pieces. However, thier cuts were not square. Ok for shelves though.
     
  5. Joey Skinner

    Joey Skinner Second Unit

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    You could use drywall screws to pull everything together insteads of clamps. You'll need a drill for pilot holes, a must for MDF.
     
  6. Chris!R

    Chris!R Auditioning

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    Amazon sells a bunch of clamps made in china for about $20 - search on columbian 27200. I've seen the same kit at my local Lowes for around the same price.
     
  7. Brent_S

    Brent_S Second Unit

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    If this is the only woodworking project you'll ever do, then even a minimum tool expenditure will defeat any cost advantages of a DIY subwoofer. If you've got a Harbor Freight near you, that'll probably be your cheapest source for bar clamps. Check their website for coupons and sale prices...sometimes prices are lower on the web than in store, so print and price match.

    The 16"x48" square edged panels appear to be a regularly stocked item at my HD. If the size works for you, check with the service desk about ordering some. Wouldn't think there'd be an extra charge since it's a stock item.

    If you can't find a way to get accurate mdf panels of the right size, the sonotube route is going to be the path of least tool expense. Even then, a cheap router, circle guide, jigsaw, and power screw gun are going to push you towards $200 or more I would think, haven't really shopped tools in a while. At minimum a Quattro15 and 240 amp will add another $200+. For $549 you can get the least expensive 12" SVS powered cylinder, less if they have any B-stock.


    wbs
     
  8. Andrew Pratt

    Andrew Pratt Producer

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    If you aren't planning on doing much more woodworking just buy a prebuilt box from PartsExpress. Their Titanic kit is actually nicely priced and makes it really easy to get your feet wet with DIY.
     
  9. Jimi C

    Jimi C Screenwriter

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    The Dayton 12" Titanic kit is around $550 and almost $700 pre-built. For this price you could get an SVS. How does this sub compare to an SVS in the same price range? Is the Dayton without a doubt a better sub?
     
  10. Jack Gilvey

    Jack Gilvey Producer

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    No. The Titanic looks like a nice kit, and it'll be smaller, but something like a 20-39 PCi would likely outperform it in the deep bass (even the PB-10 might). I've done a bunch of DIY, and have a few SVS, and it's tough to justify DIY from a pure cost perspective anymore with the likes of them around, at least in this range. If you don't have all the tools, it gets tougher.
     
  11. Brent_S

    Brent_S Second Unit

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    PE's Titanic kits are sealed designs. The 12" models out to -10.5db @ 20hz, -3db @ 37hz without room gain. With room gain, these should sound very nice. However, output will be lower than SVS, especially in the 20-30hz range. Most (all?) of the SVS designs are flat (less than -3db) to their tuning points.

    The Titanic in a vented cabinet is a different story... 3.5 ft^3 tuned to 20hz, models to -1.7db @ 20hz. It's also good for 109.6db @20hz vs. the sealed cabinet's [email protected] Thats works out to a single vented Titanic having output roughly equivalent to three sealed Titanics. You'll get similar output numbers from the DVC12 sealed and vented.

    These numbers probably put the Titanic Mk3 somewhere between the SV ISD and Plus drivers in performance. The Titanic will cost you $160 and the 500 watt plate amps are either $230 or $300. So, you're looking at a minimum of $400ish w/o a cabinet to approximate the performance of a single driver SVS. Save $50 if you use a DVC12 instead.

    Ok...we can do a dangerously shaky extrapolation here. Comparing Titanic's WinISD sim numbers vs. the PB12-Plus review over at Secrets, where the PB12+ was measured outdoors, which should approximate WinISD's models. The single driver PB12+ hit 101.5db @ 20hz at 2 meters, so add 3db for 104.5 db at 1 meter for comparison to WinISD models. That's not quite as much advantage as I was expecting, but still the equivalent of two sealed Titanics. The adjusted 1 meter number for the PB10 is 97db @ 20hz. Wish someone had similar real world measurements of a Titanic, sealed or vented. I'm not very comfortable with my extrapolation saying a single vented Titanic almost has the output of two PB12+ at 20hz.

    Still, comparing DIY to SVS is a little different than comparing it to other companies. If I remember correctly, the guys behind SV met in DIY forums like this one and took their hobby interests to the next level. Needless to say, they made DIY much less cost effective for high performance solutions. Compare the Titanic kits to anything you're likely to find at Circuit City/Best Buy and I wouldn't even think twice before ordering the Titanic and spending an hour installing the driver and amp.

    DIY *does* give you the satisfaction of the accomplishment. It also opens up designs to fit your particular environment in terms of cabinet shape and finish. It's only less expensive if you can write off the tools and time as fun money.


    wbs
     
  12. Jack Gilvey

    Jack Gilvey Producer

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    Agreed. And, for the vast majority of designs out there, DIY actually can be cheaper, depends on your goal. Certainly one can approach the performance of that 12" $4500 Ariel sub (TC driver, 4" flared port like PE carries) for a fraction of the cost, to say nothing of mega-buck Wilson and Krell statements. And, with IB, you can really blow the doors off.
    It's only something like the PB10 that gives me pause. When I first got that thing in the house, I was amazed...I don't think I could really outdo that for much cheaper.
     
  13. Brent_S

    Brent_S Second Unit

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    Jack,

    just reread the Secrets PB12+ review. Looks like the SVS amp was the limiting factor in their output tests. Makes me feel a *little* better (teensy bit) about extrapolating PB+ measurements vs. Titanic models. The Plus driver could have that extra 5db output or more in it, but SV didn't want the warranty issues or THD of running it closer to its limits. After all, it's not unreasonable to believe that any number of drivers we have access to could resemble the Plus, or even Ultra driver...if there's a DIY market willing to pay for it, someone will make it available.

    Of possible interest to the original topic of this thread. Several years ago, a friend of mine was ready to make the jump to a real subwoofer. We talked a bit about me building something for him. In the end, I advised and he ended up with a 20-39 PC+. There just wasn't enough savings to not go with the turn key solution from SVS. Especially when they offered a warranty. :b

    wbs
     
  14. Joe-M

    Joe-M Auditioning

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    I know that this home theater forum but it since this sub is going to be used primarily for music, I'm not sure that ultra low bass should be the primary goal. Musicality will should be the primary concern. Many good home theater subs are great for shaking the house down but far from ideal for listening to music.

    Overall though, I think there is potential to get both with this plan.
     
  15. Blaine_M

    Blaine_M Second Unit

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    If the sub is just for music why not go with a PB-10? I love mine for music applications. Another option could be the GR-Research design. I just built one for a friend, very musical tight sub with a passive radiator. I'm selling my PB-10 if someone is interested, still has almost 2 years of warranty on it.
     
  16. Chuck Bogie

    Chuck Bogie Second Unit

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    If having the guys at Home Depot cut the stuff, try to make as much stuff "line up" as possible. For instance, on my 3 cubic foot sealed boxes, I had 'em do a cut to get the piece that would be the sides, top and bottom all the same length. Then set the saw to length, and did widths. Since you're not changing the settings, they should at least be close. You _can_ do the hole with a drill, a pencil, string, and a jigsaw. Just take your time, and don't hurry.

    My sonotube subs are simple. I did two 26" endcaps, and sized the sonotube to be 5.5 cubic feet. Didn't do end inserts - just cinched down the four pieces of allthread with high density windowstripping around the sonotube. Hard part was cutting the holes.
     
  17. Chuck Bogie

    Chuck Bogie Second Unit

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    Okay - the Home Depot guys won't take tips.

    Guy just cut 4x24x48 pieces and 8x24x22.5 pieces, and I'm going back tomorrow for one more set of the 24x48s...

    Not sure if they're exact size, but they're consistent, and I suspect, given the care the nice young man was giving the project, that they're gonna fit nicely. Using Gorilla Glue, 2" screws, and clamps. Building the box with 3 4" toilet flange ports (bondo at the rim) between the two subs, and two braces between the subs and the ports.
     

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