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I was looking for old post on this two and one in particulare It had Dukk saying "I only do this one a year to see what kind of responce it gets" But I can't find it. It had the best and origonal description.
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Ow ow ow found it now that I look at it The Buzz Found it but this is the most in portent part of the post! It comes from the thread "Calling Dukk" http://www.termpro.com/ubb/Forum8/HTML/000124.html
quote: posted 07-25-99 12:01 PM -------------------------------------------------------------------------------- Ok, here it comes one time! I only explain these in detail once a year (I make $$ on them ) For that DVC 15. Build a box with 2 chambers, one at 3 cuft and the other one EXACTLY half of that, ie 1.5 cuft. Next cut 3 ports all IDENTICAL in length. Put one in the face of each chamber and the third in the wall separating the two chambers. In this instance each port would be either 12.5" long for a little deeper response or 8" long for a little more SPL. Now you have a box with a big chamber with a vent in it, a small chamber with a vent in it, and a third vent in the wall between the two. The woofer also mounts in the large chamber. The way they work is that, at low frequencies, it all functions as one big box with 2 ports, and is tuned to 30Hz (12.5") or 35HZ (8"). At higher frequencies the middle port starts to restrict air movement and the second chamber begins to act more as a resonance chamber but not as part of the box. At this point a second tuning frequency develops 1.9 times (almost an octave) higher than the lower one , ie. either at 57Hz (12.5") or 67Hz (8"). This is similar to a vented bandpass but has more output and smoother sound due to the woofer not being tucked inside the box. The results are that it plays both low and loud, while being relatively nice sounding. The drawback is the box size.
Did one 2 years ago in a sedan with 1 12 on 400 watts and pulled a 138 on music. There's a guy around here with 2 DVC 15s like this in a Daytona off a single 800a2 pulling 149s. They work but can be intense to build. They are the ONLY box I take care to factor exactly both port displacement and woofer displacement. Mess one of these up and they work very poorly....
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
The Big Show The Dukk says: Know your bass: PORT your damn box!! Have HoleSaw, Will Travel!
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Dukk, that's an amazing formula for an ABC box!! They always look so complicated when I see them, but you explained it so clearly and easily. Thanks!! I'm gonna do that as a project some time. I compute the box for 2 ports at my selected frequency right? And when I'm doing box size, I gotta add the woofer displacement to the bigger box's size right?
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I was just about to ask another ABC question a week ago when it hit me to do a search. Found way too much information, got confused, hit my head on the desk and passed out.
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Posts: 323 | From: Great Falls, Montana | Registered: Feb 2000
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Alot of times I'll understand stuff but wonder how the heck to build it. (ex: You've got a port between the two chambers in an ABC, whaddya do, lube it with glue and stick it in the opening?) I'm gonna take woodworking Junior year so I can build my own boxes, and I'll fit electronics in somewhere.
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Posts: 323 | From: Great Falls, Montana | Registered: Feb 2000
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All right Dukk, about that $$ that you make on those ABC boxes, since I can't have you make mine, if you come to Arizona, dinner's on me! Thanks for the help.
