TimVG Posted November 5, 2012 Report Share Posted November 5, 2012 Hi everyone This looks like a good place to log my first DIY project, so I hope it's OK. A little bit of background. I currently own two JTR Captivator subwoofers (2012 model), after experimenting with a port plug (which basically tunes the subs to 12hz), I'm totally convinced of the benefits of ULF. The only downside with the captivators is the occasional port noise with very low uncovered content, this doesn't happen a lot, but when it does it is distracting for me. I looked at some options: -Build a new box for the captivators with a lower tuning frequency: too much of a hassle to make a compromise between port speed and port resonance with a driver that works in an enclosure this small. It would be guesstimating work at best and even if it works out I'm left with two cabinets that are useless and take up space. -Build a bigger LLT (or multiples) from scratch with different drivers: These look very worthwile but I just don't have the kind of space available for the kind of subs I'd be happy with. -Multiple sealed subs: I've owned a tripple opposed sub that I had build for me with 6 ten inch drivers, and I really liked that sub despite having little room gain in my previous room, it wasn't enough for me in the end but I really liked the design. I also tried the dual captivators stacked with all ports plugged and I determined that this would be the absolute minimum in terms of SPL I'd be going after. It was good, but no match for the caps in 12hz tuning mode. Living in Europe I don't have a lot of choice in terms of drivers that are readily available at a good price. I'm wasn't going to import drivers for various reasons (warranty, shipping and custom hassles), keeping in mind that I wanted to spend as little money as possible, it wasn't going to be easy. The Sundown drivers are available over here, but it would've set me back more than I was willing to spend. So I continued to search. I'm not going to through all the drivers I considered, but by chance I found a dealer a couple of hours away from here who still had a bunch of Exodus Shiva-X drivers in stock (all tested and fully functional) for very little money. I modelled them and 8 of them in four 3,5cuft boxes should be enough for my needs, and with an FP14k clone and a minidsp already in my possession I'm safe on that part of the chain as well. So I placed my order and collected some drivers last weekend. One shiva-x And the rest of 'em The MDF has been ordered as well and will be CNC cut next week. So hopefully the build can start next week. I'm really looking forward comparing this setup to the captivators! Tim Link to comment Share on other sites More sharing options...
maxmercy Posted November 5, 2012 Report Share Posted November 5, 2012 Very interesting. Will be keeping tabs on this thread. JSS Link to comment Share on other sites More sharing options...
Infrasonic Posted November 5, 2012 Report Share Posted November 5, 2012 Damn! Thought this thread was Max's build thread. Tim, how about sealing up the Caps? Those with your triple opposed 10's should do the trick, yeah? Link to comment Share on other sites More sharing options...
TimVG Posted November 5, 2012 Author Report Share Posted November 5, 2012 I sold off the triple opposed sub actually! I tried the caps in sealed mode (+EQ down low), it worked, but they had a lot more capability with one port open. I really don't want to hit the limit with a system, and I think I could have found them with just two stacked (sealed) captivators. The powered version of the sealed captivator has nice compressors on board (just like the submersive and many other commercial subs) But I want a flat curve at all levels, so I need more displacement I think eight 12" subs with 25mm of stroke should do the trick.. If not I can always add the caps as sealed subs in the end. Although if these perform as I think they will, I'll more then probably sell off the caps. Link to comment Share on other sites More sharing options...
Bossobass Dave Posted November 6, 2012 Report Share Posted November 6, 2012 Hi Tim, Do you have a FR graph for the Caps in 12 Hz tune? Just wondering how far it drops by 12 Hz. 8x12" is a formidable system if done right. Interested to see how long you run it before you tell us you need 16x12" Link to comment Share on other sites More sharing options...
TimVG Posted November 6, 2012 Author Report Share Posted November 6, 2012 Hi Tim, Do you have a FR graph for the Caps in 12 Hz tune? Just wondering how far it drops by 12 Hz. 8x12" is a formidable system if done right. Interested to see how long you run it before you tell us you need 16x12" This is from the listening position, Dave. With and without house curve and a waterfall. I'd love 16 x 12" But I wouldn't know where to place them, the ceiling slopes down to one side so it wouldn't be symmetrical. I think (and hope) I'm doing it right. The given power rating for the drivers is 600w program, in the given box size it models to 75% of xmax at 10hz with that power rating in mind, only going over xmax below 5hz (where there will probably be some signal rolloff anyway). So box, drivers and amplification should, in theory at least, be a good match in this case. Link to comment Share on other sites More sharing options...
maxmercy Posted November 6, 2012 Report Share Posted November 6, 2012 I think (and hope) I'm doing it right. The given power rating for the drivers is 600w program, in the given box size it models to 75% of xmax at 10hz with that power rating in mind, only going over xmax below 5hz (where there will probably be some signal rolloff anyway). So box, drivers and amplification should, in theory at least, be a good match in this case. This is the kind of thinking more people should do. You should have a great system when completed. Very nice freq response, is that unsmoothed? JSS Link to comment Share on other sites More sharing options...
TimVG Posted November 6, 2012 Author Report Share Posted November 6, 2012 The waterfall is with no smoothing. I'm not sure if the FR has 1/12th smoothing or not, as it looks just a tad smoother than the WF. It sounds pretty good nonetheless. The house curve was added because I rarely watch movies higher than -6 on the receiver btw, this gave everything some more weight down low to get closer to the effect you'd have playing at reference. And thanks for the comment. I did try to think this one through. If anyone has more tips or suggestions, I'd be happy to read them. Tim Link to comment Share on other sites More sharing options...
Ricci Posted November 7, 2012 Report Share Posted November 7, 2012 The one time that I ever heard a Shiva I was impressed and so were a lot of other people there. 8 of them should make a really nice system. Link to comment Share on other sites More sharing options...
TimVG Posted November 29, 2012 Author Report Share Posted November 29, 2012 Link to comment Share on other sites More sharing options...
TimVG Posted November 29, 2012 Author Report Share Posted November 29, 2012 Tomorrow: install double baffle, sand and fill screw holes. Link to comment Share on other sites More sharing options...
Ricci Posted November 30, 2012 Report Share Posted November 30, 2012 Looks good. 1 down 3 to go. How big is your room? Link to comment Share on other sites More sharing options...
maxmercy Posted December 1, 2012 Report Share Posted December 1, 2012 Lurking.... JSS Link to comment Share on other sites More sharing options...
TimVG Posted December 1, 2012 Author Report Share Posted December 1, 2012 Looks good. 1 down 3 to go. How big is your room? It's about 1250 cu ft, but open to the rest of the L shaped room which puts it at 4500 cu ft. I haven't been able to continue building yet, as I'm down with the flue. I was feeling ill on thursday as well but couldn't resist to start building. I hope to continue on monday. I'm going to build one extra for a friend who was looking for a better movie experience, he now has a small sealed sub with a 10" peerless driver, I told him one of these would make a good upgrade. Link to comment Share on other sites More sharing options...
Ricci Posted December 1, 2012 Report Share Posted December 1, 2012 Hope you feel better soon. I'm not looking forward to my encounter with that stuff which seems to happen every winter. Link to comment Share on other sites More sharing options...
TimVG Posted December 3, 2012 Author Report Share Posted December 3, 2012 Sanded down after the first coat of epoxy. This one's going to my friend and I'd like to make it as smooth as possible. Link to comment Share on other sites More sharing options...
maxmercy Posted December 4, 2012 Report Share Posted December 4, 2012 Epoxy???? JSS Link to comment Share on other sites More sharing options...
TimVG Posted December 4, 2012 Author Report Share Posted December 4, 2012 It's a two component wood filler, we refer to it as epoxy (even says so on the container). I use it to fill the screw holes and the treat the grained edges so they don't stick out after painting. Link to comment Share on other sites More sharing options...
TimVG Posted December 4, 2012 Author Report Share Posted December 4, 2012 Priming Link to comment Share on other sites More sharing options...
TimVG Posted December 6, 2012 Author Report Share Posted December 6, 2012 first coat of white lacquer paint And while the paint dries Sorry the for the lousy quality, ipod. Link to comment Share on other sites More sharing options...
TimVG Posted December 7, 2012 Author Report Share Posted December 7, 2012 Link to comment Share on other sites More sharing options...
maxmercy Posted December 8, 2012 Report Share Posted December 8, 2012 Lookin' good! JSS Link to comment Share on other sites More sharing options...
TimVG Posted December 8, 2012 Author Report Share Posted December 8, 2012 Fired one up today (the one for my friend). It's a good sub, a bit limited by the Crown Xti 1000 but more then enough for him. I didn't have enough time to fully optimize the DSP yet but I'll go back tomorrow or next wednesday and take a picture or two while I'm there. Link to comment Share on other sites More sharing options...
maxmercy Posted December 9, 2012 Report Share Posted December 9, 2012 Being amp limited vs driver distortion limited is a good thing. Measurements? JSS Link to comment Share on other sites More sharing options...
TimVG Posted December 9, 2012 Author Report Share Posted December 9, 2012 Wednesday, together with a finished picture :-) Link to comment Share on other sites More sharing options...
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