My DIY Sub project

Discussion in 'Home Theater Projects' started by MichaelBAr, Jan 20, 2004.

  1. MichaelBAr

    MichaelBAr Stunt Coordinator

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    sorry about my 2 other threads, but I just want to organize my project because the other threads were going off topic, so this title is more universal.

    First of all my budget is probably $200 a little more maybe. Its so low because I'm 15(don't got much money) and my room isn't too big. I'll give dimensions later. I was thinking of a 10" - 12" driver. At least 100watt amp etc. I'll go into picking that stuff later. My concern now is my cabinet.

    Where Can I get blue prints in building one? Can't find any, and the prebuilt ones are more expensive than i thought.
     
  2. Mark gas

    Mark gas Second Unit

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    you can get a Dayton 12 from parts express for $115 and I think MCM may still have thier 250 watt plate amps for $89.
     
  3. MichaelBAr

    MichaelBAr Stunt Coordinator

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    Thanks I found blue prints for the shiva driver at adireaudio and I was wondering if the design can be used to fit other drivers? (such as dayton) Is there design good? I'm new to this, and this is the only blue print that I can find.
     
  4. Gerry S

    Gerry S Stunt Coordinator

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    I used plans from adire audio.

    I built the 85L Shiva in a vented cabinet. Since they were out of the Shiva driver, I used a Dayton 12" DVC driver (from parts express) instead.

    They have several plans at that site for varying budgets, so take a look around.

    -Gerry
     
  5. MichaelBAr

    MichaelBAr Stunt Coordinator

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    so are the cabs generally easy to make (adire design)? I'm not going to build it. I'm going to ask my friends dad who is a carpenter (as a hobby). How much would it cost on average for all the wood.
     
  6. Wayne Ernst

    Wayne Ernst Cinematographer

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    (1) 4' x 8' 1" (48" x 96") sheet of MDF: $19.00 @ Home Depot
    (1) PVC tube (if you are going vented): $5.00 @ Home Depot
    Polyfill: Under $20.00 (depending on your design and how much you need) from Wal-Mart
    Screws, glue: $8.00
    Spray paint: $6.00 (to finish the cabinet off)

    That's about it.
     
  7. Joe Ku

    Joe Ku Stunt Coordinator

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    If you can live with a roughly 2' x 2' x 2' box check out the Dayton Quatro 15" ($84) and the MCM $89 amp. I am building this soon for my brother in law, should be loud and low for about $200-$225. my calcs say over 110db with an F3 around 22hz. I have to draw up plans anyway, so if you are intrested I could send a copy to you. Let me know.
     
  8. MichaelBAr

    MichaelBAr Stunt Coordinator

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    what does it mean to be vented? is there going to be a pipe sticking out the back? Is vented that much better, because I'm not going to leave it on for very long times. I don't think. How much watts should my amp be? I was thinking at least 100-120. That should be enough right.
     
  9. Rory Buszka

    Rory Buszka Supporting Actor

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    It seems to me you could use the Dayton 8" driver and the Parts Express 100W amplifier which puts out 85 watts into 8 ohms.
     
  10. Rory Buszka

    Rory Buszka Supporting Actor

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    Vented is exactly the same as bass-reflex. The port does not stick out of the box. I have seen some projects where people chose to put on a port that stck out of the box to get lower tunings, but generally when this happens people build a passive radiator design. No need for you to worry about what that is. That Quatro 15" sub looks very good for the money.
     
  11. Joe Ku

    Joe Ku Stunt Coordinator

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    The amount of power you need depends on the efficiency of the driver you are using. For example, a driver with a 84db efficiency could produce 108db with 128 watts of power while a 90 db efficient sub could produce 114 db with the same power. Total system efficiency depends on the combination of driver and box. The lower a driver can play (lower Fs) the less efficient it will be. The larger the diameter of a driver the more efficient it will be. These are all general rules, and it gets more complicated but I am trying to put it in simpler terms. As far as total power is concerned, it is always better to have more power than you need. Many more subs are blown due to insufficient power than too much.
     
  12. MichaelBAr

    MichaelBAr Stunt Coordinator

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    Oh I think i understand. So first I must come up with a driver then the amp. If i get a 500watt amp and use it for a 85watt max driver then I really wouldn'd neeed all that excess wattage. Did I get that right? What if my driver was designed for more wattage than my amp? Is that just plain dumb.
     
  13. Wayne Ernst

    Wayne Ernst Cinematographer

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    It will usually be OK. The only time when it would not be acceptable is if the driver required, for example, 40 watts of power to get it "kicking" and you only had a 25 watt amp.
     
  14. MichaelBAr

    MichaelBAr Stunt Coordinator

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    my room dimmensions are 12x12x8 What size driver should I get and how much watts. Would a nice powerful 8" driver with high powered amp have the same sound as a decent 12" driver and medium powered amp. What I'm trying to ask is: Are bigger drivers always better than smaller ones (if space wasn't an issue).
     
  15. Joe Ku

    Joe Ku Stunt Coordinator

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    Volume of air swept is the important factor for sub, so usually bigger is better. However you could have a 12" sub with a big X-max that displaces as much air as a 15" with a small X-max (this is not uncommon). It is all about the volume of air it can move. The driver I suggested is a relitively short stroke 15", but it is relitively efficient so it will be able to attain great output levels with only 250w. The AV-12 (long stroke 12") I have with 350w amp will not get quite as loud as the 15" quatro with only 250w. Another thing to consider is that drivers designed for larger boxes are usually more efficient. Here is a great example. Check out the carver sunfire subs, tiny tiny boxes with long stroke subs that require 2500w to reach the same output level of the 15" quatro with 250w. You will always need more power in a small box.

    Efficiency goes down as the Fs (resonant frequency) of the driver goes down. The lower the Fs the lower the sub will be able to play. Most car subs have a high Fs and high efficiency because they can rely on cabin gain to play the low notes. But in a home sub these do not go low enough to make good HT subs.

    The power rating on a sub doesn't mean much at all. You will reach the mechanical limits of the sub before you hit the thermal limits. Even a "powerful" 8" sub will have a hard time hitting the low notes required of a good HT sub. I would recommend a minimum of 10"

    The best way to see what I am talking about is to download a copy of WinISD and model a few subs. You will quickly see the relationships I am trying to describe. I modeled many subs before I decided on the 15" quatro for my brother in law. His requirements were that it be loud and low and as cheap as possible, but did not care about size. You need to decide what the most important qualities are for you first before you can pick a suitable driver. You will not be able to build something that is low, loud, small, and cheap. You have to decide which of these you don't really need.
     
  16. MichaelBAr

    MichaelBAr Stunt Coordinator

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    ok, well size isn't an issue. The only real issue is cost (around $200-220). For loudness, I don't care much how loud it can go because I don't turn up my speakers too much because my mom is often sleeping (Her room is next to mine). When no body is home (or spleeping) I still don't like to turn it up real loud.

    I mostly listen to music but I want it for movies as well. I don't know if I want it to be better for movies or music, so both. I want clarity and don't care too much on how low it would go (I don't think so, would I really notice?). I want to feel like I'm in an earthquake (Just Kidding)

    My speakers make me happy but I want an extra emphasis on the bass (what a sub is for). Before I was serious in buying/building a sub I went to best buy and saw a cheap 75watt sony sub and noticed how much of a difference it made.
     
  17. Frank Carter

    Frank Carter Screenwriter

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    Here's some idea's for saving money, if you have or can find any old cheap receiver, it can be used to power the subwoofer. I've had great success powering a DIY sub using a spare Yamaha receiver. Even if you find some old receiver on ebay it would work, all you do is just go from the sub out on your main receiver to something like the cd input(or any other) and just run speaker wire to the sub. If you don't want to do this, then MCM's 250W plate amp for $89 is a killer deal, but they only have like 8 in stock right now.

    You can also make a post in the hardware for sale/trade forum here asking for anyone who's selling a used driver. I picked up a Dayton DVC12 for $65 shipped for my parents sub . If you're ready to buy jump on over now and look for the people selling SVS drivers. I saw two people recently saw two people selling them and you won't find a better deal on a driver so I would hurry before they're snatched up(it'll give performance similar to a Shiva). It will also work well using the Shiva's vented plans for the 95L SBB4 alignment and the 142.5L EBS alignment.
     
  18. MichaelBAr

    MichaelBAr Stunt Coordinator

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    ok, well I have a technics reciever that doesn't have sub out (darn). Its older I guess. Can I just connect speakers to sub then sub to reciever? I hear you can do that with active subs.
     
  19. MichaelBAr

    MichaelBAr Stunt Coordinator

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    I'll look into the drivers, but where else can I get drivers and amps besides Parts Express.
     
  20. Frank Carter

    Frank Carter Screenwriter

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    Yes hooking it up the way you describe will work, but it will need to be through through something like the MCM plate amp because you'll need the crossover built into the plate amp.
     

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