My First DIY Sub Question

Discussion in 'Archived Threads 2001-2004' started by Mel Silva, Oct 13, 2002.

  1. Mel Silva

    Mel Silva Agent

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    Hi everyone,
    I have been reading posts and searching for information since last Sunday. I've tried to accomplish my goals and educate myself without asking a lot of annoying questions, but I guess I going to anyway. I was directed to HTF by the AVS Forum when I asked about getting new speakers for my HT system that I am slowly revamping. Some people suggested DIY for cost savings/performance ratio, since I have champagne taste on a beer budget.

    Very basically, I want to build a Sub first and then build or buy the rest of my HT sound system around the sub. I have an old Technics rack system with Pro-Logic I that I am upgrading. The first part was to buy a Denon 3802, I have that now. I was planning on replacing the speakers in sets rather than all at once (volatile IT job market, blah, blah...) and I was going to start with the sub, then the mains and CC as a set (planning on Definitive Technology or maybe some more DIY if this goes well) and finally the surrounds.

    First, does this make any sense? Is my logic all goofed up?

    Assuming my logic is not flawed, I started looking at sub kits. I chose to look at kits since a)I'm not entirely certain that I want to spend nights and weekends for the next few months learning how to design enclosures, b)I'm pretty handy with my table saw and router, and c)I have read very few good things on subs costing less than $1K.

    What I have not been able to determine is if anyone has actually built any of these kits. I was specifically looking at the Adire SUB-V kit using a Shiva. Since I have read so much about the Shiva driver, I wanted to use one, but I didn't want to build a Sonitube and the ported enclosure seemed middle of the road on cost/performance.

    My design goals are to fill the HT room with good sub-bass without filling it full of speaker cabinets. I have no idea what frequency I want the sub tuned to or how to know what measurement of output I need (another reason to use a kit, I guess).

    The room is 14' wide with a 2/3 wall on the left (of the audience) that is semi-open to the stairs, and 21' open in the center to the two-story foyer and a large glass arch. The ceiling is 8' at the screen side then it slopes up to 10' at a 45 deg angle and continues at 10' to the back of the room.

    I think I have provided most of the information I have seen requested by other posters. Help, I don't know where to start!

    Mel
    Houston
     
  2. Dustin B

    Dustin B Producer

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    Kits or published and proven designs are the way to go with speakers unless you really know what you are doing and have good measurement equipment.
    Don't get hung up on purchasing a kit though, especially with subs. The only things you really need to order are the driver and amp (some times ports or passive radiators and specialty connectors like binding posts). Everything else you can buy locally.
    If you don't care to learn or think you can learn about tuning and what not, and given you want a box and not a tube, just follow one of Adire's reference design plans.
    Here are the vented plans for the Shiva and Tempest:
    http://www.adireaudio.com/Files/Vent...plications.PDF
    http://www.adireaudio.com/Files/Vent...plications.PDF
    As to which design you want to build and whether to go Shiva or Tempest we need some more information. Namely what is your budget for the project and can you be more specific on size contraints (you hinted that you want smaller enclosures, but do you want
     
  3. Mel Silva

    Mel Silva Agent

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    Thanks Dustin, I have viewed your specific DIY projects extensively and am very impressed with your work. Though I was unable to determine how you decided on your design for the Sonosub or The Twins. Mathematically I like the effects of about 250L (LspCAD), but I have no idea how that sounds. I feel like a blind man trying to decide if I want red paint or blue. Aesthetically, I like the size of The Twins. Acoustically, I have no idea.

    I would say that monetarily I could budget about $600 for a sub kit (driver, amp, plans, MDF) plus the little niggling things that add up but come later (laminate, stain, finish, etc)

    Mel
     
  4. Dustin B

    Dustin B Producer

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    In both cases it was a combination of largest size acceptable (sonosub - room space, twins - amount of sonotube left). The Twins volume was also choosen becuase a full length FP4 port kit would tune that volume to ~20hz.

    The smaller you go and the higher you tune the more mid bass punch you get and the closer to the typical boom box commercial sub you'll get. The larger you go and lower you tune the better the sub sounds (in general anyways, and within certain windows for each driver). I'm sure there are some optimal (for output anyways, sound quality optimal will change depending on goal and taste) numbers that you can arrive at with extensive testing of different enclosures. But who can build several dozen subs and test them all to find it. The thing is, even in a slightly sub optimal allignment these drivers will run circles around what you find commercially at the same price.

    So for a Shiva an enclosure some where in the 100-140 liter range and tuned in the 18-22 hertz range won't disappoint (I like a 4" flared port). For a Tempest, 200-340 liters tuned in the 16-20 hertz range won't disappoint either (I like a 6" straight or flared port or dual 4" flared ports). What you choose in this range may not be optimal, but it won't be far off that optimal. Which will result in a sub that will run circles around equivalently priced commercial models.

    If that is $600USD. It should easily cover everything you need for a Shiva or Tempest based sub. May or may not cover the veneer, depends on how exotic you get there. Excluding finish a Tempest can be done for ~$400USD.
     
  5. Mel Silva

    Mel Silva Agent

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    Based on Dustin's comments and feedback, I have ordered the port, driver and amp for the 142.5L Vented Shiva Box. Wish me luck.

    I'll post some pictures when it is finished.

    Mel
     

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