Derrick824 Posted March 3, 2008 Report Share Posted March 3, 2008 Previously I had a pair of Bl 18s in a 10ft box w/ four 6" ports tuned to 32hz powered by a pair of Sundown 1500s (pushing about 3200watts). It did a best of 148.3 @ 41hz. I recently built a new box and added a 3rd Bl 18 to my setup and wired my Sundowns down to 0.5ohm each. The last box worked well so the new one is proportionally larger at 15ft w/ six 6" ports tuned to 32hz. I was expecting some good #s but they are very disappointing. It was all installed Thursday night and hit a 147.9. The new sub was still stiff. After a day of breaking in, Friday it hit a 148.2. I did a lot of demoing Saturday at a competition and now today it hit a 148.4. Very disappointing #s considering I added a 50% more cone area. At first it was obvious the new sub wasn't moving anywhere near as much as the other two but now its doing just a good. I've checked & rechecked all the wiring and everything is good. All settings have been tweaked & re checked and they're good. We played a little with box position sliding it forward and back without any better results. I tested the amps and they putting out 3644watts (1215watts per sub) which is enough to get them moving. I can only guess that I'm getting some sort of cancellation somewhere. The weird part is that my last box with just a two subs moved a ton of air. The only thing thats not proportional to this new setup is that I had more power per sub with just a pair (1600watts each and now 1215watts each). Also I'm seeing much better increases by metering in the kick or with the door open. Previously I've only seen a consistant increase of 0.1 by going to the kick panel. Today it did 0.7db better with a 149.1 sealed in the kick and a 150.4 door open & mic in the kick. I've never seen increases like this so I'm thinking its a symptom to whatever the problem is. Anyone have any ideas? Here are some pics of the current box. Thanks for any help. Link to comment Share on other sites More sharing options...
dwright27 Posted March 3, 2008 Report Share Posted March 3, 2008 add another amp and youll see a rise i believe. you upped cone area but lost power to each sub. when you only had 2 each sub was seeing 1600 RMS. now you have three they're seeing just over 100 each. 2006 F-150 4 DC XL M2 18's Walled Daily Driver XS Power 4 DC 3.5kw Team DC Team S.P.L. Lot of Audio Technix and 1/0 DC Audio Dealer American Bass Dealer XS Power Dealer Audio Technix Dealer Link to comment Share on other sites More sharing options...
Thewes Posted March 3, 2008 Report Share Posted March 3, 2008 I had a similar problem in my Escalade, Derrick, I dont know if cancellation is common in GM cars or what. In my situation I went from one 15'' BL to two 15'' BLs and I even added a second sundown 1500. So each sub was getting 1500 watts but it sounded as if I was running out of phase, checked everything, even down to the 9v test. I just gave up and have half my equipment sitting in my room while only running one sub, sounds alot better than when both were hooked up... But in your situation it could be a number of things. Good luck figuring it out though, what is your voltage looking at while running both amps at .5? Link to comment Share on other sites More sharing options...
Derrick824 Posted March 3, 2008 Author Report Share Posted March 3, 2008 I had a similar problem in my Escalade, Derrick, I dont know if cancellation is common in GM cars or what. In my situation I went from one 15'' BL to two 15'' BLs and I even added a second sundown 1500. So each sub was getting 1500 watts but it sounded as if I was running out of phase, checked everything, even down to the 9v test. I just gave up and have half my equipment sitting in my room while only running one sub, sounds alot better than when both were hooked up... But in your situation it could be a number of things. Good luck figuring it out though, what is your voltage looking at while running both amps at .5? I went through three different boxes with just a pair of subs and didn't have any problems. Now I don't know what the deal is. I have checked everything I can without ripping stuff apart. Nothing is out of phase. Everything is wired correctly. The box specs are good. On big bass hits my voltage drops to 11.8. Thats the lowest I've seen. I have a pair of Optima G31s in the back right at the amps. Link to comment Share on other sites More sharing options...
Thewes Posted March 4, 2008 Report Share Posted March 4, 2008 I went through three different boxes with just a pair of subs and didn't have any problems. Now I don't know what the deal is. I have checked everything I can without ripping stuff apart. Nothing is out of phase. Everything is wired correctly. The box specs are good. On big bass hits my voltage drops to 11.8. Thats the lowest I've seen. I have a pair of Optima G31s in the back right at the amps. All I can think of is those sundowns pushing 3 amps at .5 ohms each is really straining them- even to the point where you are losing efficiency if that makes any sense. So you said your new box is proportionate to your old one in regards to tuning and such? Maybe you should try to add some more port area, change it up. I honestly don't understand why you are hitting about the same score with 50% more cone area. Link to comment Share on other sites More sharing options...
dwright27 Posted March 4, 2008 Report Share Posted March 4, 2008 because he lost a thid of the power to each sub! your moving the same amount of air with less power and more cone area i believe. but i could be wrong. grab anbother Sundown 2006 F-150 4 DC XL M2 18's Walled Daily Driver XS Power 4 DC 3.5kw Team DC Team S.P.L. Lot of Audio Technix and 1/0 DC Audio Dealer American Bass Dealer XS Power Dealer Audio Technix Dealer Link to comment Share on other sites More sharing options...
banginAltima Posted March 4, 2008 Report Share Posted March 4, 2008 because he lost a thid of the power to each sub!your moving the same amount of air with less power and more cone area i believe. but i could be wrong. grab anbother Sundown Well of course he is going to see a gain with another amp. I idea was to see an increase just by added a third sub. If you build it, db's will come... NSPL World Record Holder Trunk 0-1800 watts---147.9 with 1722 clamped watts @ 40Hz(9-20-09). Competition Only Record Holder Trunk 0-500 watts---148.1 2006 Nissan Altima 3.5 SE Currently Rebuilding.... My 150db Plus Trunk Build I do box designs. [benH] 6:24 pm: clipping doesn't really hurt subs [benH] 6:24 pm: being an idiot is what blows subs Link to comment Share on other sites More sharing options...
Derrick824 Posted March 4, 2008 Author Report Share Posted March 4, 2008 More and more its looking like an issue of power ratio. I added 50% more cone are but only about 20% more power. Its time to test out the big T5k on these. (T5k = T4k w/ 5K birthsheet) Link to comment Share on other sites More sharing options...
dwright27 Posted March 5, 2008 Report Share Posted March 5, 2008 More and more its looking like an issue of power ratio. I added 50% more cone are but only about 20% more power. Its time to test out the big T5k on these. (T5k = T4k w/ 5K birthsheet) YES!!!!!!! 2006 F-150 4 DC XL M2 18's Walled Daily Driver XS Power 4 DC 3.5kw Team DC Team S.P.L. Lot of Audio Technix and 1/0 DC Audio Dealer American Bass Dealer XS Power Dealer Audio Technix Dealer Link to comment Share on other sites More sharing options...
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