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  1. #1
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    want to get started in speaker building

    hello,
    i posted a while ago a speaker box i made out of cardboard for fun.Then i got more into it, and i built a legitimate nice boombox out of 1/2 inch MDF board, two 5 1/4 woofers, and some small automotive tweeters. I used a crossover i got from another speaker set. I used an amp that is not too good, i will say..
    is not really too good.
    http://www.parts-express.com/pe/show...number=310-304

    The amps that the ratings were inflated. It was rated for 45 watts RMS but it only put out about 25, with a good bit of distortion. So, i got a MUCH better amp, with a true 50 wpc at 8 ohms with 5.0 thd at full power, 0.1 at 30 watts rms. it sounds much louder, and cleaner at higher volumes. Im running an unsafe combination of speakers, though, because i have two 6 ohm woofers, and two 16 ohm tweeters. the pair in parallel comes down to about 3-4 ohms, and the amp if ran to long on that low of an impedance can damage the amplifier. So, i figured another way to wire it, that is parrallel series. Yes, you can wire 4 (must be 4 or more speakers to accomplish) in a series/parellel hookup. using this, i can get all four speakers to show a load of 8.56 ohms. Perfect for the amp, which works very well between 6-8 ohms, which is reccomended by the manufacture.

    this is the new amp-
    http://www.parts-express.com/pe/show...number=300-383

    But, im really clueless on the other abbriviations, like mms, cms, vas, q, etc. and i would like to get more familiar with it all so i can build better boxes in the future. I tried to build a sub box but all my measurements were bad, since i did it all by hand with no help from the internet to design it. It was a L port box with one 10 inch woofer with about 2 sqft of space inside, the dimensions were 24x12x12. Port at first was 2 incches wide,it went 10 inches in, and 20 inches down.



    ______24 in_____________
    (.._____20in__________....)-----this is a diagram i tried to make to describe my situation. it
    (................................)....)-----Didnt work very well, the box size was way to big, and the
    ( ...............................)....)12 in ---compliance wasnt stiff enough. it sounded like a free air
    (.................10 inch > )....)-----speaker, which is not what i wanted. This is a top view.
    (___________________)....)-----the dots represent free space.
    22 in

    my main reason for making this thread once again is to find somthing to get me more into the subject, like actually knowing how to build a speaker box with correct specs for a given speaker, and have it actually sound good. Ive been trying to research a ton the last couple of days, and i havent come up with much. If anyone could provide any help to guide me in the right direction with a web page describing everything, or maybe a forum the help me out. anything helps. Thanks! if anyone wants to see the two boxes i built, (one IS very nice, to me anyways.. the one with 5 1/4 speakers) just ask.
    Last edited by thecoolman101; 03-01-2013 at 09:30 AM.
    if you want me to i can break your truck for free!

  2. #2
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    There are way too many shapes and sizes of boxes. The best thing you can do is pick out a speaker, not less than 10". You won't tight hard bass, without distortion, with a smaller sub. Once you have a sub, then look in the manual or call the manufacturer for the recommended volume for an enclosure and what size the port should be, if you have a port at all. I believe the output power of the amp is irrelivant as far as the size of the box. I dont think the shape of the box matters, as long as you have the proper volume. Have a look HERE
    Who needs nitro, when you got LiPo?

  3. #3
    RC Champion
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    Shape does change performance.
    One thing you don't want is a square box.
    Mainly..you don't want the side that has the sub mounted to it to be at the same angle as the side behind the sub.
    This is why most pre-fab boxes you see are some sort of wedge shape.
    --
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  4. #4
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    and make sure you have a big enough box but not to big the area inside the box needs to be right or you will not get full performance out of the sub, and just like anything else you get what you pay for buy a 10" at walmart it be ok, get a good 10" from a audio store like some rockfords etc.. lots of brands you will vibrate everything around you. Just if you put this in a vehicle rubber seal everything so we dont here the dang trunk rattle that kills the sound of a system. I hear that and think stupid lol.
    Let's Go Steelers!!!... KCCO

  5. #5
    RC Champion
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    Lol, I am a little bit more advanced than you guys thing I am.. I am not going to be buying boxes, speakers, most likely just buying amps. My father is a garbage drunk driver and finds speakers all the time, to bring me up to mess with. Also, I want to build my boxes, not buy them. And timber, that's the problem I had with the 10 inch box, it was oversized, and wouldn't compress the air. Compliance was way off, if I had two 10's instead of just one I think it would have sounded better. Also, being only 1/2 inch thick, I had a lot of flex it it. I'm gonna cut the box in half essentially, and try to see if it's any better. Cut the long sides from 24 in he's to about 14-16 or whatever will get me between. 0.7 and 1.0 cubes of air. I bet it will help. I'll keep the L port design, if that doesn't sound to good, I'll put in a 2-3 inch diameter port and I'll determine how long it will be. And thank you guys for helping.
    if you want me to i can break your truck for free!

  6. #6
    RC Turnbuckle Jr. rjm2519's Avatar
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    I think you have some editing to do in your previous post, read carefully about what your dad is...lol. Box material is also very important as well as shape size port size and of course the speaker itself. If you really want to build boxes, fiberglass is the way to go along with mdf.

    Sent from my Torch!
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  7. #7
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    Wow sounds cool, I've been thinking about buying or trying to make a box for my 72 chevy maybe you can help!

  8. #8
    RC Champion
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    Ahhh man, I see the error.. But it won't let me fix it! Ohh well. It's garbage truck* driver. Lol good catch. And johnzilla, I can give some tips, but I'm still starting out myself. I have just a little bit of experience.
    if you want me to i can break your truck for free!

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