ZachG Posted August 25, 2012 Report Share Posted August 25, 2012 Ok so I got a 98 grand prix gtp. I got 2 obsidian 12s on 1.5k Right now they are in a 3.5cu box after port tuned to 32hz facing my trunk lid. The rear deck in my car flexes up about a Inch or two and my trunk and rear bumper flex about a inch. If I flip the box around and face it front to the cabin with the arm rest down will it be louder and stop some flex? 1998 Pontiac grand prix gtp supercharged2 12" Obsidain Audio V.1 on a 2011 zx1500.1 at 2 ohms. 20ft of Knuconceptz CCA 0 Guage. 2nd Battery is a Shurken BT-120. Box is 3.5cu tuned at 31.8hz sealed off from the trunk. 14sqft of Dynamat on the Rear deck top & bottom. Soon to be more for doors/roof. Gets low & loud Did a 140.5 Sealed at Battle of the boom in June 2013 dropping to 12.7v (need a alt mines going bad) Link to comment Share on other sites More sharing options...
Joe X Posted August 25, 2012 Report Share Posted August 25, 2012 YES! flex will be reduced and it will get louder. Test port/subs forward and back see what you like best. You can attempt a seal off for even less flex and more output. Link to comment Share on other sites More sharing options...
ZachG Posted August 27, 2012 Author Report Share Posted August 27, 2012 YES! flex will be reduced and it will get louder. Test port/subs forward and back see what you like best. You can attempt a seal off for even less flex and more output. I saw on here a few weeks ago someone that didn't want to permently seal off and didn't want to use expanding foam to do so. He said he was going to use pool noodles so he wouldn't ruin the inside of his truck. Think its possible for me to do the same thing in my trunk.? 1998 Pontiac grand prix gtp supercharged2 12" Obsidain Audio V.1 on a 2011 zx1500.1 at 2 ohms. 20ft of Knuconceptz CCA 0 Guage. 2nd Battery is a Shurken BT-120. Box is 3.5cu tuned at 31.8hz sealed off from the trunk. 14sqft of Dynamat on the Rear deck top & bottom. Soon to be more for doors/roof. Gets low & loud Did a 140.5 Sealed at Battle of the boom in June 2013 dropping to 12.7v (need a alt mines going bad) Link to comment Share on other sites More sharing options...
Joe X Posted August 27, 2012 Report Share Posted August 27, 2012 YES! flex will be reduced and it will get louder. Test port/subs forward and back see what you like best. You can attempt a seal off for even less flex and more output. I saw on here a few weeks ago someone that didn't want to permently seal off and didn't want to use expanding foam to do so. He said he was going to use pool noodles so he wouldn't ruin the inside of his truck. Think its possible for me to do the same thing in my trunk.? The seal off has to be literally air tight, never heard of someone trying that Link to comment Share on other sites More sharing options...
ZachG Posted August 27, 2012 Author Report Share Posted August 27, 2012 YES! flex will be reduced and it will get louder. Test port/subs forward and back see what you like best. You can attempt a seal off for even less flex and more output. I saw on here a few weeks ago someone that didn't want to permently seal off and didn't want to use expanding foam to do so. He said he was going to use pool noodles so he wouldn't ruin the inside of his truck. Think its possible for me to do the same thing in my trunk.? The seal off has to be literally air tight, never heard of someone trying that So is there any other way to do it then useing expanding foam, I don't want to ruin my car 1998 Pontiac grand prix gtp supercharged2 12" Obsidain Audio V.1 on a 2011 zx1500.1 at 2 ohms. 20ft of Knuconceptz CCA 0 Guage. 2nd Battery is a Shurken BT-120. Box is 3.5cu tuned at 31.8hz sealed off from the trunk. 14sqft of Dynamat on the Rear deck top & bottom. Soon to be more for doors/roof. Gets low & loud Did a 140.5 Sealed at Battle of the boom in June 2013 dropping to 12.7v (need a alt mines going bad) Link to comment Share on other sites More sharing options...
Berto Posted August 27, 2012 Report Share Posted August 27, 2012 Just get some of those heavy duty trash bags (Home Depot, Lowes, etc) and spray the expanding foam in them instead of just straight into the trunk. Try to get as narrow bags as possible, that way there isn't much waste. TEAM FLEX ISSUES Car: 1985 Oldsmobile Delta 88 Royal 24" Rims HU: 7" Carputer, Planet Audio EQ, iPhone. Coax: T3 Audio 4" speakers Subs: 2x 18" T3 Audio TSNS (walled) Sub Amp: DC 9k SOON TO COME T3 Audio 6x9s MB Quarts 6.5" comp set MAYBE ADDED 2nd DC 9k Link to comment Share on other sites More sharing options...
nik12937 Posted August 27, 2012 Report Share Posted August 27, 2012 I own an 05 Grand Prix, trunk design is very similar, and facing my subs forward is actually quieter in my opinion. I covered my lid in about 5 layers of some sound deadening and sprayed expanding foam inside of all the chambers I could get to. It wasn't messy and definitely improved the transient response of my P3's. A kid I know says he's running 3000 watts to an MTX sub. I kept my expectations low since most people think MAX is what the amp produces. Look in his car, amplifier is not only a BOSS, but says 3000 watts max, 500 watts rms... WHAT?! Link to comment Share on other sites More sharing options...
ZachG Posted August 28, 2012 Author Report Share Posted August 28, 2012 I own an 05 Grand Prix, trunk design is very similar, and facing my subs forward is actually quieter in my opinion. I covered my lid in about 5 layers of some sound deadening and sprayed expanding foam inside of all the chambers I could get to. It wasn't messy and definitely improved the transient response of my P3's. With my last setup it was quieter faceing Foward then the trunk lid but quieter. Going to try with this one tomorrow maybe 1998 Pontiac grand prix gtp supercharged2 12" Obsidain Audio V.1 on a 2011 zx1500.1 at 2 ohms. 20ft of Knuconceptz CCA 0 Guage. 2nd Battery is a Shurken BT-120. Box is 3.5cu tuned at 31.8hz sealed off from the trunk. 14sqft of Dynamat on the Rear deck top & bottom. Soon to be more for doors/roof. Gets low & loud Did a 140.5 Sealed at Battle of the boom in June 2013 dropping to 12.7v (need a alt mines going bad) Link to comment Share on other sites More sharing options...
ZachG Posted August 29, 2012 Author Report Share Posted August 29, 2012 YES! flex will be reduced and it will get louder. Test port/subs forward and back see what you like best. You can attempt a seal off for even less flex and more output. Ok so I faced then Foward today and the out put is about 3x less then when they were facing the trunk lid. Lot less flex on the trunk and inside the car but still much quieter. It's a bitch and a half to switch around cause my battery and box and amp have to come out. But guess they will be swapped again and ill deal with the flex. 1998 Pontiac grand prix gtp supercharged2 12" Obsidain Audio V.1 on a 2011 zx1500.1 at 2 ohms. 20ft of Knuconceptz CCA 0 Guage. 2nd Battery is a Shurken BT-120. Box is 3.5cu tuned at 31.8hz sealed off from the trunk. 14sqft of Dynamat on the Rear deck top & bottom. Soon to be more for doors/roof. Gets low & loud Did a 140.5 Sealed at Battle of the boom in June 2013 dropping to 12.7v (need a alt mines going bad) Link to comment Share on other sites More sharing options...
Berto Posted August 29, 2012 Report Share Posted August 29, 2012 They're most likely quieter because the port is getting stuffed by the back of your seats. Build a new box with the port in the center. TEAM FLEX ISSUES Car: 1985 Oldsmobile Delta 88 Royal 24" Rims HU: 7" Carputer, Planet Audio EQ, iPhone. Coax: T3 Audio 4" speakers Subs: 2x 18" T3 Audio TSNS (walled) Sub Amp: DC 9k SOON TO COME T3 Audio 6x9s MB Quarts 6.5" comp set MAYBE ADDED 2nd DC 9k Link to comment Share on other sites More sharing options...
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