Mario Posted November 20, 2012 Report Share Posted November 20, 2012 Hello, my name is Mario, I'm Italian .. I have a question for you, I hope you can help me. My car is a FIAT BRAVA, precisely this: http://www.dadedepo...._file/brava.jpg do I have a Rockford Fosgate subwoofer t215d2, is currently playing in a box of 107 liters tuned to 31Hz, but as it is easy to think, plays decently only slow songs and various, and ultra low notes ... I'd like to play a little bit of everything, I could not help but hear the notes ultra low, but if you could, it would be better. Other than that, I'd like to be able to listen well and with a nice punch, even house music, dance and stuff like that ... But unfortunately I do not know how to build this box. I am really very practical to build, but I can not define the liters and the frequency of the system ... I have two amps, both class D 1) EMPHASER EA1800D (2200WRMS DECLARES A 1ohm) 2) LANZAR OPTI2000D (1700WRMS DECLARES A 1ohm) You which would you choose? which one is the best? thank you very much to all Link to comment Share on other sites More sharing options...
Joe X Posted November 20, 2012 Report Share Posted November 20, 2012 Your box is nearly 40% bigger than recommended, this usually makes the sub/box response peaky and you may also have increased group delay, fit the symptoms you describe. Also how are your sub and port aimings? What is your port area? it would be nice to post all the dimensions of the box and the port. You can use either amp provided that you setup your gains properly and watch that you have the bass boost defeated or your LPF not set too low, I wouldn't say that the amp is to blame for the problem you have although you can try both and see if there are any differences. Link to comment Share on other sites More sharing options...
alaskanzx5 Posted November 20, 2012 Report Share Posted November 20, 2012 How port area do you have? I've been told to much port area can make it peaky to. Try a box that's 2.5-2.75 cuft (don't know what that is in liters) tuned to about 35hz. If you do a slot port try and keep the port area between 12-14" per cuff and if you do a round port the port should be between about 9-10" per cuft t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Mario Posted November 20, 2012 Author Report Share Posted November 20, 2012 Your box is nearly 40% bigger than recommended, this usually makes the sub/box response peaky and you may also have increased group delay, fit the symptoms you describe. Also how are your sub and port aimings? What is your port area? it would be nice to post all the dimensions of the box and the port. You can use either amp provided that you setup your gains properly and watch that you have the bass boost defeated or your LPF not set too low, I wouldn't say that the amp is to blame for the problem you have although you can try both and see if there are any differences. wow, even 40%? on the website, I think I read that to get the best performance in terms of sound pressure, it was necessary to create a box around 120 liters. maybe I'm wrong ... however, my box is very big, but I can not say with precision measurements, height, length and depth, this is because the box is in the car, and the car is in the garage, away from my home at this time. .. I can anticiparti that the sub is facing up, while the port, eg a tube of 16cm in diameter (internally 15.4 cm), length 40cm. this tube is instead facing the tailgate. the box is about 10cm high in most of the subwoofer .... How port area do you have? I've been told to much port area can make it peaky to. Try a box that's 2.5-2.75 cuft (don't know what that is in liters) tuned to about 35hz. If you do a slot port try and keep the port area between 12-14" per cuff and if you do a round port the port should be between about 9-10" per cuft then advise me to reduce the volume of the box and make a highest frequency? in terms of acoustic performance and sound pressure, the L PORT is better of the cylindrical tube? Link to comment Share on other sites More sharing options...
alaskanzx5 Posted November 20, 2012 Report Share Posted November 20, 2012 the type of port is completely up to you. some people prefer round ports while others slot ports. a round port will take up less airspace where a slot port takes up more. a round port is easy to swap out to change tuning while a slot port cant be changed in the easiest of ways a round port has needs less volume but with the l port using more volume you could move more air if going for more for a better sq change the round port out to where the box is tuned a littler higher. cut an inch or 2 off reinstall listen to it and if you feel like its needed cut another inch or 2 off and keep repeating until you get the sound you want. build a slightly smaller box tuned the the freq you found to sound best to you from doing the above. the box shouldn't be more then 2.75 cu ft after displacement if you are over power the sub its better to be on the smaller side. could also try turning the box to face different directions. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Mario Posted November 20, 2012 Author Report Share Posted November 20, 2012 the type of port is completely up to you. some people prefer round ports while others slot ports. a round port will take up less airspace where a slot port takes up more. a round port is easy to swap out to change tuning while a slot port cant be changed in the easiest of ways a round port has needs less volume but with the l port using more volume you could move more air if going for more for a better sq change the round port out to where the box is tuned a littler higher. cut an inch or 2 off reinstall listen to it and if you feel like its needed cut another inch or 2 off and keep repeating until you get the sound you want. build a slightly smaller box tuned the the freq you found to sound best to you from doing the above. the box shouldn't be more then 2.75 cu ft after displacement if you are over power the sub its better to be on the smaller side. could also try turning the box to face different directions. okay. summing up: I first have to find the right frequency for me, shortening the tube a little at a time, trying again and again, then when I found this frequency, build a box smaller than the current one, which is not greater than 2.75 cu ft. (77-78liters) .. so far everything is ok! but the box must be 2.75cu ft., or will I make it slightly larger, because the subwoofer and round port takes up volume? also making it so small, do not risk not to hear the ultra low notes? I'd like to get a result that allows me to hear everything very well! Link to comment Share on other sites More sharing options...
alaskanzx5 Posted November 20, 2012 Report Share Posted November 20, 2012 the box in total will be bigger then the 2.75 cuft but after the port sub and any bracing you want to add is in it needs to be right around 2.75 cuft and if you are gonna be overpowering the sub slightly smaller then the 2.75 would be better. keep the port area on the lower end of the recomended (9-12" per cuft for round ports if im not mistaken) and you should have a great sounding box. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Joe X Posted November 20, 2012 Report Share Posted November 20, 2012 the type of port is completely up to you. some people prefer round ports while others slot ports. a round port will take up less airspace where a slot port takes up more. a round port is easy to swap out to change tuning while a slot port cant be changed in the easiest of ways a round port has needs less volume but with the l port using more volume you could move more air if going for more for a better sq change the round port out to where the box is tuned a littler higher. cut an inch or 2 off reinstall listen to it and if you feel like its needed cut another inch or 2 off and keep repeating until you get the sound you want. build a slightly smaller box tuned the the freq you found to sound best to you from doing the above. the box shouldn't be more then 2.75 cu ft after displacement if you are over power the sub its better to be on the smaller side. could also try turning the box to face different directions. okay. summing up: I first have to find the right frequency for me, shortening the tube a little at a time, trying again and again, then when I found this frequency, build a box smaller than the current one, which is not greater than 2.75 cu ft. (77-78liters) .. so far everything is ok! but the box must be 2.75cu ft., or will I make it slightly larger, because the subwoofer and round port takes up volume? also making it so small, do not risk not to hear the ultra low notes? I'd like to get a result that allows me to hear everything very well! In my opinion is best for you to give the external dimensions of the box, boxes have 3 diferent volumes which are external, gross internal and net volume, what needs to be corrected is the net volume to volume to 2.7 cubes or so, the 107 liters is 3.8 cubic feet and I think you will probably need to mod your box somehow since it's a big difference IF that is the net volume you are giving. It is not necessary to get ultra precise measurements, just within 1 centimeter of error would be enough. Link to comment Share on other sites More sharing options...
alaskanzx5 Posted November 20, 2012 Report Share Posted November 20, 2012 joe knows a lot when it comes to boxes. if he asks for info i would really do my best if i was you to provide that info. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
focas23 Posted November 20, 2012 Report Share Posted November 20, 2012 no getting wat your sayn Link to comment Share on other sites More sharing options...
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