I want to build a sub! Am I biting off more than I can chew?

Discussion in 'Home Theater Projects' started by keoni, Jan 16, 2004.

  1. keoni

    keoni Agent

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    So I know nothing but all this speaker building business has me very interested. I love woodworking and the prospect of building a quality sub for cheap while having a cabinet to match my decor is a very attractive option, over the premade over priced Best Buy stuff I have been hearing. I am going to need a sub adequate for HT/and Music for a 15 X 15 room, nothing to big.

    I am looking at the Dayton 10-12 inch Titanics, or any other high quality subs that size designed for sealed enclosures that could be recommended. A have read a sealed enclosure is easier for a first project, that I can make with some sort of plan.

    1) I know I need an amp, probably 250 watt. Is there any other hardware (wires, etc) that I need? Or does the Amp connect directly to the driver?

    2) I know what crossovers are used for but I am not sure if I need one for a single driver sub? Do I?

    3) how small could I make this? I have read that shape matters little whereas size/space matters more. True? I would like a smaller sub.

    4) I am going to have to get better at sodering I assume. How much sodering is involved in a project like this?

    5) If I am using a 6.1 reciever with 8 ohms to 6 channels can I still use a 4 ohm driver for the sub? I assume I can since if I connect the reciever to the sub with an RCA type sub cable and its a powered sub then it wont matter at all.

    Any information is appreciated, your teaching a baby to walk. I have legs, but when I look at them I am not quite getting how this works. I have seen some of the kits on partsexpress that claim one hour build time, that is perfect, but I would prefer to have all the hardware and make my own cabinet out of fine materials. I am assuming I would need to brace the driver and am not sure how I would do this.


    I know I could REALLY get into making my own audio equipment but all the tech talk and equations have me rattled.It would be really nice if someone could tell me exactly what I need, and what I need to do to start this project.Thanks for any advice you can provide.
     
  2. marc_manny

    marc_manny Stunt Coordinator

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    I am also looking at building my own sub. The one I am look at is a 15" tempest with a 250watt plate amp.

    Try looking at Adire.com. They have a 12" shiva which a lot of people have talked about as being good. Adire also has documentation (size and how to build cabinet) on different shiva application.

    All you need is an amp, a driver, and a cabinet to store them in. You do not need a crossover for a subwoofer. Most receivers have pre outs for subs, and then the amp also handles some of the filtering of the higher frequencies.

    Marc
     
  3. Mike Keith

    Mike Keith Second Unit

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    I don't know of any Receivers that provide a built-in amplifier for a sub so it wont matter, you will be using a separate amp connected to the LFE output of the Receiver to give lo-pass signals to the Sub Amp.


    A subwoofer is a good first time project, their relatively easy for beginners, and IMO the best and most rewarding place to start. The room will have more effect on the sound then any of the details of alignment or enclosure size, that’s where things get tricky.
     
  4. Kenneth Harden

    Kenneth Harden Screenwriter

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    All I can say is, you can get the plans and parts from the internet, easily, but good woodworking skills are just that, skills, and art, and if you have them, you can get good plans and make a beautiful sub.

    The lack of skills and tools is what is keeping my from building my own speakers. Thats why Parts Express is selling boxes now.
     
  5. keoni

    keoni Agent

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    Wow, more help than I could imagine. Thanks for your great answers
     
  6. Andrew S-

    Andrew S- Stunt Coordinator

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    And the impedance or ohm load of your sub does not matter to the reciever. It matters to the amp.

    Most plat amps put out most power at 4ohms so that would be perfect. Just make sure before you hook it up.
     
  7. keoni

    keoni Agent

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    Where is a good place where I could find good plans for making the sub cabinet? I would like something to make out of MDF that I could surround with some finer grade material like oak to match my decor. Does Adire offer good cabinet plans? Or do I have to make my own?
     
  8. Ben L C

    Ben L C Agent

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  9. Wayne Ernst

    Wayne Ernst Cinematographer

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    Actually, if you do utilize one of the Parts Express subwoofer drivers, they have spring terminals on the speaker itself. You just compress the terminal and instert the wire into the space. When you release the terminal, the wire is securely held. As mentioned, you can use the crimp terminal for the wire connection that connects to the plate amplifer, though. However, no soldering is required.

    Now, if a Shiva is purchased, you could use the crimp/spade connector on the speaker end of the wires, too because the spring terminals do no come on the Shiva. But, it's still a great driver - regardless. [​IMG]
     
  10. PaulDF

    PaulDF Second Unit

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    Keoni, you love woodworking, and you seem to have a strong desire to learn... You are definitely not biting off more than you can chew.

    Most of your questions have already been answered, but I'll throw in my two cents as I was in your shoes just two years ago.

    Sealed vs ported is not such a big deal in my opinion as far as building the cabinet. Either way you need a box simulation program to simulate the approximate frequency response curve you want... For movies a flat (all frequencies at the same loudness level) response curve is usually desired. This gives you an accurate reproduction with all sounds at the proper level.

    BUT, in my opinion, for music, a lot of people like (or are used to) a hump in the response around 50-60 hertz, which gives you a little more wham in the bass.

    You can design your subwoofer to respond however you want. Usually it is a compromise between the two when doing double duty. This is an important factor and must be understood. One way around this is with equalization. Build a sub with a flat response for movies, and use the EQ to boost the signal in the 50-60 hz region when listening to music. Perhaps out of range for a "budget" system, but very versatile.

    Another thing. If you are truly on a budget, then you might want to change your views on size. There is a basic law out there that there are three main factors when simulating a subwoofer. Power, Size (cabinet volume), and SPL (loudness). You can pick only TWO out of the three. A small cabinet to go loud will require a lot of power. A larger cabinet will require less power to go louder. This is why a lot of DIY subs built on a budget are quite large compared to commercial units. There are more reasons such as shipping of commercial units(requiring smaller size), but basically bigger subs are not so bad.

    Adire does offer variations of cab plans for the Tempest, Shiva etc. Cabinet simulation programs such as Unibox or WinISD also let you choose your own. Definitely build with MDF as it has the right properties, and is very easy to work with, besides the dust... Also, don't be thinking you'll build the thing in 1 hour! If you had a prebuilt cab you could slap it all together in an hour, but to build the cabinet will take many hours, as will designing it if you so choose.

    It might all sound quite complicated but it really isn't. I am just poor at explaining it. I started out like you, and I ended up with a refrigerator sized sub in my basement and it has truly redefined bass for me. Coupled with the EQ, I can get any kind of bass I want!
     
  11. Bob K

    Bob K Stunt Coordinator

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    Keoni,

    If you're an experienced woodworker, you can build a sub no problem. Pick a proven design using one of the Parts Express or Adire drivers and matching plate amp. Both of these outfits (and others) have many vocal proponents; you really can't go wrong. One of the nice things about Adire is that they have plans right on their website -- I built the "mid-Q" sealed Tempest with an AVA 250W plate amp, with very minor additions.

    In terms of attaching the driver to the plate amp, different people have different techniques, as you see. I solder wires to the driver, then attach those wires to the wires from the plate amp using Radio Shack "Euro Style Terminals", but to each his own. If you decide to solder and want to practice, just buy a bunch of resistors and a board from Radio Shack or the equivalent and practice a bit first. I have two left thumbs; if I can do it, anyone can.

    It's really a blast! Have fun!

    Tempest Construction Pix: http://www.audiocircle.com/circles/m...view_album.php
     
  12. TeddM

    TeddM Agent

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    There's an excellent website belonging to Sean Collins that feature a tower design NHT 1259 based subwoofer. I built one with thicker cabinet walls. I tried to post the url but I have less then 15 postings so I cannot do so. Use Google and "Sean Collin's NHT 125" as the search entry. I discovered polyurethane glue and how to do solid wood corners off of Sean's extensive website. And if anyone wants pictures of my sub I built, email me at [email protected]. It came out beautifully and was my first speaker project.
     
  13. MichaelBAr

    MichaelBAr Stunt Coordinator

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    Whats crossover? is that connecting the speaker to sub then sub to reciever?
     
  14. douglas-b

    douglas-b Stunt Coordinator

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  15. keoni

    keoni Agent

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    Ok I am going to go for it. I am thinking I am going with a 12 inch Shiva/Dayton Titanic MK II with a 250 watt amp in a sealed box. Would this work well for a Hometheater/Music application in a 15 X 15 room if I am not to picky about hitting ultra lows? What box size should I use for his application? I was also wondering if there was a way to figure out the cabinet size I need with internal bracing, the driver etc. The formulas for determining cabinet size etc make me want to cry, are these formulas inteded for vented enclosures? I need to buy a book!
     
  16. Wayne Ernst

    Wayne Ernst Cinematographer

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    Heck yes - it would be great. In regards to cabinet sizes, check out the Adire Audio Web site. They have many .PDF format plans for boxes. If you go with the Shiva, consider an 85L ported design. It should provide you a good "mix" of bass for both home theater and music listening.
     
  17. keoni

    keoni Agent

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    Thanks Wayne. Much appreciated.
     

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