Jeff4661 Posted January 4, 2015 Report Share Posted January 4, 2015 Ok so I once again am changing box design instead of a ported I am going to go with a 4th order. I have been using winISD to help me plan this. Please keep in mind this is my first 4th order. Just wondering about a few things prior to desinging it all out A few myths/questions I would like some answers on. 1) port tuning needs to be around 44-47hz for lows? WinISD shows my box would be -3db at 30-31hz truth? Opinions? 2) less subs,higher ratio is better than more subs in a smaller ratio box? 2 12s in a 1:3 ratio box will yield more output then 4 12s 1:2 ratio.. ( just examples) 3) higher ratio with less power is as loud as lower ratio more power? 4) how much port velocity is to much for a 4th order? My winISD box currently has around 65.5 ft/s or around 21m/s is that to much? What is a good ratio for a loud daily/spl box? 1:2? Thease are just a few I have been seeing lately if you guys could help clear the air of these myths? Also here is a place I found some more information to maybe help some people on 4th orders http://mobileaudioforum.com/forum/showthread.php?1619-Thought-I-d-share-some-4th-order-design-info Thanks guys, Current build 05 Yukon SLT http://www.stevemeadedesigns.com/board/topic/195350-jeffs-05-yukong-wall-build/ Link to comment Share on other sites More sharing options...
Phaeton Posted January 4, 2015 Report Share Posted January 4, 2015 my 4th order is a 1:2 ratio, its tuned to 47ish hz, one 18 and the whole thing takes up 10 cubic feet of room. It hits lows, its loud and i like it. dont know much else to be honest 1997 subaru legacy outback Four 15's in a almost wall Rockford Fosgate t2500-1bdcp Rockford Fosgate T400-4 on tweets Rockford Fosgate T400-4 on highs Rockford Fosgate T400-2 on midrange Rockford Fosgate T400-2 on midbass Optima Yellow top batteries 270A Singer alt (working on a bracket for a second) Lots of Second Skin Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 4, 2015 Report Share Posted January 4, 2015 Can you post your specs from WinISD? I'd like to take a look. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Jeff4661 Posted January 4, 2015 Author Report Share Posted January 4, 2015 Can you post your specs from WinISD? I'd like to take a look. My computer isn't hooked up to the internet... And I haven't figured out how to post pictures off of my smart phone Current build 05 Yukon SLT http://www.stevemeadedesigns.com/board/topic/195350-jeffs-05-yukong-wall-build/ Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 5, 2015 Report Share Posted January 5, 2015 My computer isn't hooked up to the internet... And I haven't figured out how to post pictures off of my smart phone Well if you just tell me what subs you are using, the rear & front volumes of your box, and the front tuning I should be able to do the rest. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Jeff4661 Posted January 5, 2015 Author Report Share Posted January 5, 2015 My computer isn't hooked up to the internet... And I haven't figured out how to post pictures off of my smart phoneWell if you just tell me what subs you are using, the rear & front volumes of your box, and the front tuning I should be able to do the rest. Ok here is the sub specs Subs are alpine bass line 12"s (for a budget build) Spl: 87.6db Re: 3.6ohm Fs: 30hz Vas: 67.8l(2.39cubic foot) Qms: 7.07 Qes: .53 Qts: .49 sd: 452cm Xmax: 10mm Xmech: 52mm Now the enlosure on winisd is as follows Rear chamber is 9 cubic foot Front is 18cubic foot 45hz tuning The port I have setup is 10"wide by 30" tall Also I am going to use polyfill in the sealed section 1.5lbs per cubic foot gaining me 30% to get to 9 cubes This is going in a 05 yukon.. the goal is to keep it behind the rear seats..I already removed the third row so I have the space I believe.. A thought I am having is to drop to 6 woofers instead Bcs of space issues? Thanks Current build 05 Yukon SLT http://www.stevemeadedesigns.com/board/topic/195350-jeffs-05-yukong-wall-build/ Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 5, 2015 Report Share Posted January 5, 2015 Thanks for the specs. I'll play around with them a bit when I get home tonight and report back. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Jeff4661 Posted January 5, 2015 Author Report Share Posted January 5, 2015 Ok yea if u can find something that works well let me know.. also let me know if I can use all 8 12s or if I have to drop back to 6 I only have 48" between the wheel wells.. My absolute Max dimensions are Width 48" Hight 33" Depth 32" Gives me a little over 25 cubes gross P.s. thanks a ton for helping man This is my first 4th order an I just want everything perfect before I built the box Current build 05 Yukon SLT http://www.stevemeadedesigns.com/board/topic/195350-jeffs-05-yukong-wall-build/ Link to comment Share on other sites More sharing options...
TaylorFade Posted January 5, 2015 Report Share Posted January 5, 2015 Tuning is based on sealed resonance. There is no hard and fast rule where tuning is "supposed" to be. It just happens to be that a ton of subs have a 40-50hz resonance in a sealed chamber of the sizes used in a single reflex. Speaking of the sealed chamber... low end extension is dictated largely by the size of that side. Larger = lower f3 (usually). If a 30hz f3 is ok for your design goals, use it. If not, make the sealed side bigger. Obviously there is a point of diminishing returns and you don't want to get too large. Ratio... the larger the ratio... the larger the gain. But at the expense of bandwidth. Depending on the sub used, you may get a fat ass peak. Meaning... your response will look like a mountain instead of a plateau. I'm sure you've seen this in WinISD. Personally... I prefer cone area to ratio. Link to comment Share on other sites More sharing options...
Jeff4661 Posted January 5, 2015 Author Report Share Posted January 5, 2015 Tuning is based on sealed resonance. There is no hard and fast rule where tuning is "supposed" to be. It just happens to be that a ton of subs have a 40-50hz resonance in a sealed chamber of the sizes used in a single reflex. Speaking of the sealed chamber... low end extension is dictated largely by the size of that side. Larger = lower f3 (usually). If a 30hz f3 is ok for your design goals, use it. If not, make the sealed side bigger. Obviously there is a point of diminishing returns and you don't want to get too large. Ratio... the larger the ratio... the larger the gain. But at the expense of bandwidth. Depending on the sub used, you may get a fat ass peak. Meaning... your response will look like a mountain instead of a plateau. I'm sure you've seen this in WinISD. Personally... I prefer cone area to ratio. Could u elaborate on the cone area ratio? What specifically do you mean by that?I've herd that 1/2 the cone are for the port area but Idk how much I trust that Current build 05 Yukon SLT http://www.stevemeadedesigns.com/board/topic/195350-jeffs-05-yukong-wall-build/ Link to comment Share on other sites More sharing options...
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