Akslowroller Posted May 14, 2012 Report Share Posted May 14, 2012 So I am new to this forum and I must say tons of great info! This topic has ahead a lot of light on a subject I have been interested in for a long time. My next build is with 4 Rockford T2 15's In a fourth order. Hopefully I can figure everything out before destroying equipment. Link to comment Share on other sites More sharing options...
Hotdog Posted May 23, 2012 Report Share Posted May 23, 2012 So I am new to this forum and I must say tons of great info! This topic has ahead a lot of light on a subject I have been interested in for a long time. My next build is with 4 Rockford T2 15's In a fourth order. Hopefully I can figure everything out before destroying equipment. Actually I talked to Rockford today and they do not recommend 4th order on there T2 series subs. The subject was brought up when asking them about doing a 4th order with the Old school RFR2215 woofers which they said would work fine in a 4th order. I am thinking of changing it up and trying a 4th order (NEW) 2004 F-150 Build Log -->http://www.stevemeadedesigns.com/board/topic/192208-hotdogs-f-150-build-log/ 2003 Mercury Mountaineer Build Log --> http://www.stevemeadedesigns.com/board/topic/114380-hotdogs-2003-mountaineer-build-log-20-removed/page__gopid__1602379#entry1602379 2008 Equinox Build Log --> http://www.stevemead...g/#entry1475764 Link to comment Share on other sites More sharing options...
Akslowroller Posted May 25, 2012 Report Share Posted May 25, 2012 Thanks for the info. Yeah I have decided my 4 15's probably wouldn't give me the numbers I'm looking for. I have decided to go with two SMD 18's but thanks for your help. Link to comment Share on other sites More sharing options...
jbiddle.com Posted August 24, 2012 Report Share Posted August 24, 2012 okay so i have a crazy one for you guys. i have been thinking and what would happen if i build a 4th order bandpass for 2 boston acoustics g5 12s built the sealed section to 1.5 cubic foot per chamber and then a 5 cubic foot common ported chamber. then put a passive radiator on with each sealed sub and then tuned the passive radiator to 30 hz. then tune the actual 5 cube ported section to 50 hz. would that work. its just something i been thinking about for a few days and all the calculations worked out but i just want personal advice before i go for it Head Unit -- Alpine CDA-9887 Mids and highs -- 2 Crescendo PWX-8's 4 Crescendo PWX-6's 4 Crescendo FT-1 Super tweeters Mids and Highs amps -- 2 Alpine V12 MRV-F545 Subs -- TBD Sub amp -- Crescendo Bass Cleff BC2000. Sub Box -- Ported box 9 cubic foot tuned to 37hz for 2 15 with 140 inch port area Processor - Alpine imprint Link to comment Share on other sites More sharing options...
donellk Posted August 24, 2012 Author Report Share Posted August 24, 2012 okay so i have a crazy one for you guys. i have been thinking and what would happen if i build a 4th order bandpass for 2 boston acoustics g5 12s built the sealed section to 1.5 cubic foot per chamber and then a 5 cubic foot common ported chamber. then put a passive radiator on with each sealed sub and then tuned the passive radiator to 30 hz. then tune the actual 5 cube ported section to 50 hz. would that work. its just something i been thinking about for a few days and all the calculations worked out but i just want personal advice before i go for it ive got to say i dont know and ive never seen anything like that but sounds cool and if itll work itll prolly be a monster lol! Team Xtreme Amperage Xtreme Audio Innovations XtremeAudioInnovations.com Facebook.com/xtremeaudio321 basics of a 4th order ~ 1993 Toyota Pickup~ 4 linked c notched bagged Fiberglass door panels (5 speakers per door) Link to comment Share on other sites More sharing options...
jbiddle.com Posted August 24, 2012 Report Share Posted August 24, 2012 i started a new thread about it go check out the box design i posted pix of my sketchup of it just wish i could figure out how to import pictures to the sub holes Head Unit -- Alpine CDA-9887 Mids and highs -- 2 Crescendo PWX-8's 4 Crescendo PWX-6's 4 Crescendo FT-1 Super tweeters Mids and Highs amps -- 2 Alpine V12 MRV-F545 Subs -- TBD Sub amp -- Crescendo Bass Cleff BC2000. Sub Box -- Ported box 9 cubic foot tuned to 37hz for 2 15 with 140 inch port area Processor - Alpine imprint Link to comment Share on other sites More sharing options...
tmac93 Posted September 10, 2012 Report Share Posted September 10, 2012 im very new to bandpass boxes, so say if i wanted to build a 4th for my 18'', and manufactors recommendations say the subs minimum sealed is 4.5cuft and 6.25cuft minimum ported i have to make one huge assssss fuckin box?!? Link to comment Share on other sites More sharing options...
StreetMetalBen Posted October 4, 2012 Report Share Posted October 4, 2012 Now here is where it gets fun... Your subwoofer needs to come from the sealed section facing into the ported section. This strikes my curiosity. I have seen tons of 4th orders with subs inverted. I think inverted is better, you can smell the coils if you screw up and it helps with the cooling. Im still wondering how much port is enough. They say to go for at least the same amount as cone area but then you get ridiculous port lengths and without screwing the gain its hard to maintain. not sure why you would go with the same amount of cone area i just worry about the sq in of the port! for every cube i do 12-18 try to keep it around 15 tho! Not to bring up an old thread, but when you say 15 Sq in per Cub, it that per Seal cube, Per Ported Cube? Or total combined Ported/sealed cubes? Thanks for the awesome writeup!!!! It made 4th orders so much easier to understand! Link to comment Share on other sites More sharing options...
StreetMetalBen Posted October 4, 2012 Report Share Posted October 4, 2012 And I'm also trying to understand the reasoning behind the number 15.... is it just the magic number? LOL Link to comment Share on other sites More sharing options...
donellk Posted October 4, 2012 Author Report Share Posted October 4, 2012 Now here is where it gets fun... Your subwoofer needs to come from the sealed section facing into the ported section. This strikes my curiosity. I have seen tons of 4th orders with subs inverted. I think inverted is better, you can smell the coils if you screw up and it helps with the cooling. Im still wondering how much port is enough. They say to go for at least the same amount as cone area but then you get ridiculous port lengths and without screwing the gain its hard to maintain. not sure why you would go with the same amount of cone area i just worry about the sq in of the port! for every cube i do 12-18 try to keep it around 15 tho! Not to bring up an old thread, but when you say 15 Sq in per Cub, it that per Seal cube, Per Ported Cube? Or total combined Ported/sealed cubes? Thanks for the awesome writeup!!!! It made 4th orders so much easier to understand! And I'm also trying to understand the reasoning behind the number 15.... is it just the magic number? LOL That would be per cuft of the ported section... No magic number just a good base measurement to stay around... I wouldnt go any lower then 12sqin per cuft to much port area is bad also lol! Team Xtreme Amperage Xtreme Audio Innovations XtremeAudioInnovations.com Facebook.com/xtremeaudio321 basics of a 4th order ~ 1993 Toyota Pickup~ 4 linked c notched bagged Fiberglass door panels (5 speakers per door) Link to comment Share on other sites More sharing options...
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