First Tempest project finally done...and it POUNDS!

Discussion in 'Home Theater Projects' started by JamesThompson, Dec 11, 2003.

  1. JamesThompson

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    Buttoned everything up last night around 11:00pm. It didn't have time to try out a lot of things, but initial impressions are great!

    The only disc I had on hand was Swordfish, so I zipped to the explosion scene at the beginning...hehe actually startled me a bit. :b Tried out a little music this morning before work and I was just as pleased.

    Tonight's job (after cleaning up my woodworking mess on the porch) is trying to calibrate my new sub and finding the best spot in the room to put it.

    You can take a peek at the process and results at this link:

    http://65.35.82.154:8000/coppermine/...s.php?album=21

    (sorry for the busted link. remove the space after the 'h' and it should work fine)

    Thanks for everybody's help in answering the questions I had along the way.

    - James T
     
  2. Joe L.

    Joe L. Stunt Coordinator

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    James,

    Great pictures. Building a DIY sub can sure make a lot of sawdust.

    I hope you did not crank it up too loud at 11:00 PM (or that other family members were warned in advance[​IMG] )

    Let us know how it sounds once you have it in place and levels set.

    Joe L.
     
  3. Kyle Richardson

    Kyle Richardson Screenwriter

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    Glad you're pleased with your project!
     
  4. Owen Bartley

    Owen Bartley Second Unit

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    Hey James, nice work! Your sub looks quite similar to mine, except for finish. Man, there's nothing like hearing your first DIY sub for the first time. Check out the final scene in Fight Club... that made my jaw drop. I was actually scared for a second because I wasn't paying attention when it kicked in.

    One thing though, you may want to break in the sub before you give it a really tough workout or calibrate it... not 100% necessary, but from what I've heard it helps. Play some mid level music (leave the radio on or something) for the week while you're at work and it will loosen things up and get it broken in a bit.
     
  5. JamesThompson

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    Owen, good point about the break-in time. I haven't thought about it, but it makes sense. Our subs are really similar. I think the legs on mine are a blatent rip-off of yours! :b Before I started, I checked out tons of sub project web sites, and I remember hitting yours at least a couple times.

    I should have plenty of time tomorrow (day off) to monkey around with it a little more and find a good spot in the room for it. I also have a couple touch-ups on the finish I need to do.

    - James
     
  6. LanceEAR

    LanceEAR Agent

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    Is that one of the Adire recommended enclosures (214L or 340L)? I'm still waiting to hear when my AV15 will ship so I've had plenty of time to decide on enclosure type/size. I've never built a sub before so I think a sealed enclosure would be easier, especially after seeing all those circle cuts! It sure would be nice to have a ported sub, though...

    TIA
     
  7. JamesThompson

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    Yep, it's the Adire Alignment Vented 214L. This was my first shot at a DIY sub, also. Believe it or not, the circle cuts were the easiest thing to get right of the entire project. Just be sure you have a router with a straight cut bit and buy (or make) a circle cut jig. With the right jig, it's almost impossible to mess up.

    - James
     
  8. LanceEAR

    LanceEAR Agent

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    That was a quick response!

    After looking at your pictures it looks like you used screws to hold things in place while you applied the clamps. Am I correct? Did you end up leaving the screws in after the glue set up and the clamps were removed?

    Thanks again.
    -Lance
     
  9. RoyceDB

    RoyceDB Extra

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    James, what amp is that?

    also, looks really good man[​IMG]. How long would you say it took you to build the box?
     
  10. JamesThompson

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    The screws were left in. I've read that they are dangerous to use, but I didn't have problems. I was sure to pre-drill every stinking hole, though. [​IMG] One reason I used the screws is I only have 3 bar clamps.

    Royce, the amp is a Parts Express 250W 300-794 (the one without bass boost). I ordered it, the tempest, and the port kits from Acoustic Visions (whom I recommend highly).

    Construction of the box took longer than the average (I'm guessing) becuase I needed to make it appealing enough to sit in the living room. I wish the stain turned out a bit better, but it'll do.

    - JamesT
     
  11. RoyceDB

    RoyceDB Extra

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    are passive radiators worth the buy? What exactly do they do, anyway:b
     
  12. Wayne Ernst

    Wayne Ernst Cinematographer

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    Awesome work !! [​IMG] [​IMG]

    The only thing better than the smell of fresh cut MDF is the feeling of bass pounding you in the chest. [​IMG] [​IMG]
     
  13. Owen Bartley

    Owen Bartley Second Unit

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    You stole my legs!!!

    Heheh, I'm glad my site was able to help someone. [​IMG] I loved this project, and tried to document the important parts. I hope you find a good spot for it... have you heard of the "put the sub in your listening position and walk around the room" trick? If not, basically, wherever the bass sounds the best is where you put the sub. Might be worth a shot if you have a long enough cable. I took tomorrow off too but I'll be painting bedrooms and picking up some flooring. Gotta keep the projects going!
     
  14. SteveLeach

    SteveLeach Stunt Coordinator

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    That's the first time I've heard of putting the sub in your listening position and then doing a walk around test. I'll keep that im mind the next time I'm positioning a sub.

    steve
     
  15. JamesThompson

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    Thanks for the walk-around idea. Turns out with my new sub in the first location I thought it should go it is almost acousticly invisible in the middle of the room. Moved to a new spot and it sounds much better. I need to rearrange the room so I can stuff it in the corner. In the meantime, I'll certainly try the walk around test.

    On another note, should adjusting the phase on the amp make a noticable difference? Maybe it's just me, but I can't tell 0 from 180? Maybe I'm not already deaf! [​IMG]

    - James
     
  16. Rory Buszka

    Rory Buszka Supporting Actor

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    The Passive Radiator Thing:

    They add cost and complexity. They allow the use of bass-reflex loading even when the reflex ports would be too long to fit in the box. Generally this is only necessary for uber-high-excursion drivers, from the AV12 on up to the Tumult. Also, if the ports were undersized in diameter to make their length fit the box, then there will be lots of port air velocity noises. By simply going with passive radiators instead of pushing physics to the limit, one can have the deep bass while eliminating the risk of port air noise. One must make sure to use passive radiators such that the combined displacement of the radiators is twice that of the woofer. With a short-excursion 15" woofer, one might be able to get away with a single long-excursion 15" PR but with a long-excursion 15" woofer, two long-excursion 15" passive radiators would be needed. Tuning passive radiators is done by adding mass to the diaphragm. If you are not building the passive radiator design, then I will not go into the tuning details now.
     
  17. Owen Bartley

    Owen Bartley Second Unit

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    James, phase can be tricky. I had to fiddle quite a bit with it to get it to integrate well in my setup. Right now I have (on loan from my brother) a pair of big Cerwin Vegas acting as my mains, and they put out a lot of bass on their own. However, I found that at some phase settings, the sub was working in opposition to the CV's. So I played some test tones on repeat, and sat in the corner and adjusted the phase with all the speakers playing until I found the sweet spot.
     
  18. Lewis Besze

    Lewis Besze Producer

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    When you do the thge "walk around" test, run test tones in both polarities,and use an spl meter.Which ever phase setting at the best spot gives you the "flattest" and "loudest" read is a good start for pahse setting and location as well.
     

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