Thinking of building a sub

Discussion in 'Home Theater Projects' started by Andrew Pezzo, May 27, 2003.

  1. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Originally I wanted to build a small high powered sub but came to the conclusion that it was going to cost to much and in effect defeat the purpose of building my own. So now I have a new idea. My current setup includes a Denon AVR-3803, Def Tech's all around, BP2006TL's for front L/R, CLR2300 center channel, and ProMonitor 80's for surrounds. The front 3 provide excellent bass and I certainly do need a stand alone sub. The idea of building one is so exciting that I want to give it a try.

    I want to keep the cost under $300. My question is would I be able to build one in my budget that goes lower than my main speakers? If not I was thinking of still making it but wiring it to my surrounds (would that be a low level connection or high level?) and setting them to large so that they provide more bass effects.

    I am veyr new at the DIY concept for speakers so try to keep that in mind with any suggestions. I would really like to make this happen so I would love to hear what some people with experience have to say. And if this turns out to be successful maybe I will make that high powered one sooner than later.
     
  2. JimRHIT

    JimRHIT Stunt Coordinator

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    Hey Andrew,
    I know what you are searching for. Back at home, I usually listen to Def Tech BP2000s, and their "claimed" 14Hz(i think) is somewhat unrealistic. They really did a good job keeping me satisfied for a while.

    But...to upgrade, I went with Adire Audio's www.adireaudio.com Tempest (a 15" subwoofer ~$150) and my own amplifier. The box cost me ~$40 in materials and about 6-7hours of good work. It was a real learning experience too. You could buy a plate amplifier from Adire, Stryke, or Parts Express and keep the price right around $300.

    The only problem is, the subwoofer was too large and I did eventually tire of its appearance, but the bass that I got for $200 was nothing short of breathtaking (when stepping up from the Definitives).

    So, if you are willing to give up a bit of space, the Tempest is a good deal.

    If not, the Stryke Audio www.stryke.com AV12 can be a very fun subwoofer in a smallish sealed up box for you. Again, ~($160 on the driver) and if you email John (the owner of Stryke), see if he can work you out a good deal on an amplifier.

    Don't be afraid if you are new to this...everyone here will try to guide you along...just don't hesitate to ask questions...even if you think that they are "new member" questions. So, pick out your sub or a few of them, and we can throw in some input and recommended boxes that are easy for you to build with even and circular saw. Have fun [​IMG]

    Jim
     
  3. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Thanks Jim, the hardest part is getting started. I am not opposed to a "big" sub but I live in a condo so space is limited. That was one reason I went with Def Techs but since I cant have 4 all around I want to beef up my rear channels as no deep bass is coming from them.

    Here is something else I need to consider. The sub will have to be placed on the back wall. The sub cable will need to be at least 40-50 feet. From what I have seen sub cables are very expensive, more than I want to spend. And since It would have to be long it would cost a fortune. This is why I think i am leaning towards a smallish sub to be wired with the surrounds.

    It sounds like I should be able to make something that fits my needs from what you are saying Jim. My next question is where should I start, finding a driver? amp?

    Now I am very excited to do this.
     
  4. JimRHIT

    JimRHIT Stunt Coordinator

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    Your idea of "beefing up" the rears is a nice idea, but if you build this subwoofer and then set the crossovers on the receiver to keep the surrounds as small, the sub will be very good at reproducing what could or should come out of those back speakers.

    "The sub will have to be placed on the back wall. The sub cable will need to be at least 40-50 feet. From what I have seen sub cables are very expensive, more than I want to spend."
    - that's why this is the DIY forum...you can even make one of those for yourself. But, that is a more daunting task...I am sure someone around here would be willing to make you one and sell it to you...let's see who chimes in here.

    If you can spare the space (2x2x3.5ft) or any way you want to shape it. I would contact Dan Wiggins at Adire Audio...he helped me with any questions that I had when I started.

    Here is another option for you:
    Do you have an old receiver lying around? Like an old pro-logic or anything that has some good power.

    I say this because that big box is very efficient. You COULD wire up the subwoofer cable to the inputs of your old receiver and send only a speaker wire to the subwoofer...saving you some cash, using your old equipment, and having a REMOTE CONTROLLED subwoofer [​IMG][​IMG]

    let those ideas float around a bit ... and see what you can see at the websites

    take care,

    jim
     
  5. Andrew Pezzo

    Andrew Pezzo Second Unit

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  6. TimForman

    TimForman Supporting Actor

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    If you go with a powered sub using a 250W plate amp you could easily put together a sub cable by purchasing a length of coax and putting some connectors on it. Not sure how you'd conceal the cable but I bet you could do it for less than 50 cents a foot.
     
  7. JimRHIT

    JimRHIT Stunt Coordinator

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    "Under this scenario I would set my rears to large since a sub would be wired with them. Otherwise if it were a truly stand alone sub using the sub out on my 3803 I see what you are saying. "
    - you would surely beef up the rears with it, but I don't think you would get that HT rumble you seem to be looking for.

    "I am still tyring to understand the whole crossover setting concept. "
    - the crossover, wherever you set it at, tell your speakers "Hey, you can't play that...so I am gonna send it somewhere else...and let you play only the stuff you can" ... and then says "here you go subwoofer".
    Since bass (the .1 in your 5.1 or 7.1 channel setup) is not directional (you can totally tell where it comes from), you can usually get a pretty convincing effect from a standalone subwoofer and most of the time, the bass may even feel like it comes from the speaker that it was originally intended for.

    Hope that helped.

    Jim
     
  8. Andrew Pezzo

    Andrew Pezzo Second Unit

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    I checked out Adire's website which leads to a whole new slew of questions. I think for this project I am going to go with the AV8. On thier website that have kits, is this something I should get? And what criteria should I use in picking out an amp? What else, besides wood, would I need?

    Sorry for all the questions but this is more confusing than I thought. Regardless I am still going to make every effort to build this sub. My feeling is that if I start small and it works out than I will make a bigger sub once I move into a house.
     
  9. TimForman

    TimForman Supporting Actor

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    Well, I have to say I'm perplexed by your choice of driver. If your Def Tech's already have powered 8" subs I think you benefit a whole lot more by going with at least a 12" but a 15" powered unit would be better. I run AV8s in my L/C/R and they get low but not that low. You could place it in the back of your room easily enough. Is there something I'm not considering?
     
  10. Tab Nichols

    Tab Nichols Stunt Coordinator

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    I would agree with Tim. You'll get a little better extension with an AV8, strictly because of a bigger cabinet, but it still wont compare to going with a larger driver.

    I think you might find yourself disappointed with the AV8 compared to what you are looking for.
     
  11. Andrew Pezzo

    Andrew Pezzo Second Unit

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    If I were to go with a 15 inch driver how big of a cabinet would I need? If I can keep that to a modest size than a 15 inch would be doable.

    I was checkig out the Tempest driver with AVA250 amp. I guess now I need to find some info on the actual building process.
     
  12. TimForman

    TimForman Supporting Actor

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    If space is a major concern you could build a sealed enclosure for the 15", then later move to vented enclosure if you decide you'd like more extension. If you decide to go with Adire they have several applications to choose from in sealed and vented enclosures. You can use Sonotube to keep your costs down. The smallest size appears to be 64L which is a very small footprint. The next size up is 122L which is about 2' x 2'. I have a sealed Tempest 122L app and it gets very low. The walls move without an audible frequency.
     
  13. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Sonotube might be the way to go for me. One thing I am having trouble finding is info on measurments, like how big tht sonotube should be or how long of a vent I need.
     
  14. Jonathan_D

    Jonathan_D Stunt Coordinator

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    Andrew, make sure you check out Adire's designs for their various subs. The Shiva may be a good compromise between performance and size and they already have proven alignments (designs) available that make building them quite painless.

    Even the 122L Tempest takes up a good bit of space. A 22" cube on 4" legs may not sound big, but once you get it built and in place you realize it's a lot bigger than you thought. My wife had suggested early on I build two of these. For the levels at which we usually listen to movies, I thought it would be serious overkill and, since the room its in is multi-functional (rather than dedicated solely to HT), take up space unnecessarily. After I got my sub built my wife commented on how big it was and how glad I hadn't gone with her suggestion to build two.

    Oh, and BTW, I can run it loud enough to rattle all the walls and shake my pants leg. Since it's on a hardwood floor it also tends to "skate" on loud passages. I've got to get some rubber "cups" for the legs to sit in to keep it still!
     
  15. TimForman

    TimForman Supporting Actor

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    As Jonathan says, you can go to the Adire website and use their volume and vent dimensions. Convert liters to cubic inches then divide that number by Pi x radius squared. For example; the 85 liter Shiva sonosub made with 14" sonotube would be about 33 3/4 inches long. That's a rough number and many purists would want to add the volume taken up by the driver and the vent tube to the total volume. Sonotube comes in many sizes. Smaller sizes can be had at home improvement stores, larger sizes at lumber yards, concrete supply or construction supply houses.
     
  16. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Thanks for the link, you guys have been a ton of help. When I originally thought about doing this I was doubtful it would really happen. Some of the other threads about DIY subs were much more involved than I anticipated. However everyone starts somewhere I suppose.

    I have a friend in Boston that is going to help me with the actual building. He has a decent shop set up in his basement and has all the tools I need. He helped construct an addition to my TV stand to accommodate my center channel speaker, looks like it was original to the rest of the stand.

    This weekend I plan to buy the driver and amp. If any progress happens soon I will let you know. Otherwise I should have done before the summer is over.
     
  17. Jonny K

    Jonny K Second Unit

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    Just another vote for the Tempest. I built one a year ago using the "Adire Alignment" - 214 liter. Well it turns out this box is HUGE, certainly bigger than you're looking for. The dimentions are 22x22, yet when it's sitting in my room it seems to just dominate.

    Yet there are other smaller plans that can be built, and based on my first DIY project, I HIGLY recommend this sub. I'm very impressed. If you make a smaller box for it, this could be an awesome sub for you! Also, from what I understand, the 12" Shiva sub is also very good. You could build a smaller sub using that driver and still get great bass (just based on what I've heard).


    Jonny K. [​IMG]
     
  18. Owen Bartley

    Owen Bartley Second Unit

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    Count me in for a Tempest vote as well. I love mine, big box and all. If you want to go a little smaller, I'm sure a Shiva would still do you well,.and I would for sure look into one of the coax cable DIY sub connection too if yours is long. ( I originally wanted to, but mine is almost right next to the equipment cabinet so it was cheaper for me to buy). If you want to get another idea on the building situation, take a look at the link in my sig.

    Hope you find what you're looking for!
     
  19. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Thanks Owen. I have a feeling once actual building is about to start I will have a few more questions. Right now I am getting what materials I can.

    On a side note, I am looking into making a long RCA cable to take advantage of the zone 2 capabilities of my receiver. Since I will need one for the sub might as well make 2 of them, maybe I can geta deal on he length of cable I need.
     
  20. TimForman

    TimForman Supporting Actor

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    MarkerTek has a good selection of bulk cable by manufacturers like Belden and Gepco plus connectors by Canare.
     

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