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I designed my box and then made plans for building it. When designing it I made sure to facter in the space taken up by the 3 ports and the divider. I have exactally 2cuft and 1cuft. I have cut all the wood and tomorrow I will put it together. I have 2 slight problems. 1. I forgot to facter in the space taken up by the speaker (12" punch dvc) 2. When cutting the wood my box shrunk because of slight in acuracys when cutting. It should be fairly close to the original intended sise. I'm going to calculate in speaker displacement and make sure I put the divider in place so that the big chamber is exactally twice the sise of the small one. Insted of 2 and 1 cuft i will probably have something like 1.9 and 0.95 cuft. How will this change my tuneing fq? I am planning on using 3" ports 12" long, what will be my 2 tuning frequencys. This will be in a daly driver and I plan on listening to all differant kinds of music so I want something that will pound super hard nomatter what I'm listening to. Are thees a good choice of port dimentions? Thanks everyone
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Posts: 78 | From: Calgary, Alberta | Registered: Jun 1999
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The part I'm concerned about is that dukk said "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...." I messed up a bit in that I made my box a tad too small, will this be anysort of a problem?
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Posts: 78 | From: Calgary, Alberta | Registered: Jun 1999
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posted
I didn't get too worried about my ABC and I actually like it... I din't thing the 0.04 cu/ft will kill it... You probably won't notice the difference anyway... IMO
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Posts: 186 | From: Grande Prairie, Alberta, Canada | Registered: May 1999
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quote: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....
to cover all of this the best way is to look ate dukks post under "calling dukk". Goto the search and look for it. Also type in abc you will get lots of info. If you have more question and you will let us know.I think I asked most of them already.
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