dcofer Posted November 26, 2011 Report Share Posted November 26, 2011 (edited) I have a Crystal CMP8 and a cheap 200w continuous amp laying around and have decided that I want to mess around with a few box designs for it for the sake of learning. I can build standard ported enclosures just fine but I have always been interested in the bandpass enclosures. Now I have frequency response equations for the fourth order bandpass and can plot them via Matlab, but beyond that I am not sure completely what I am looking for in a design. I have gotten the flattest response with a 2:1 sealed:ported tuned to 55hz with minimal gain and a f3l~32hz, f3h~80hz and when I do 2:1 ported:sealed the f3 stays about the same but the gain is stupid high around the tuning frequency with no real plateau. And many of the fourth orders I have seen buiild have larger ported chambers then sealed. My question is what should I really focus on for a fourth order bandpass enclosurewhen it comes to gain and how much I should worry about the flatness of the response curve? The plan is loud and clear on music, as much as I like to see numbers I do not compete currently. Please dun just respond telling me to buy a plan, and I'm not looking for professionals to divulge secrets, just rules of thumb. This is for learning and a project when I have time off work. If this were for a serious build I would just purchase a plan so its done right, but its not. Thanks EDIT: I can post my MATLAB graphs if requested to see what I am gettign via my equations. Edited November 26, 2011 by dcofer Quote Link to comment Share on other sites More sharing options...
AmericanLegend Posted November 27, 2011 Report Share Posted November 27, 2011 Hey you're on matlab, you must be an engineering student lol. Bandpass are known to be louder than ported or sealed, but the group delay can be higher which some view as muddiness in the bass. I say you can't hear group delay if the subs are banging your ears apart. 2:1 can be appropriate, but it will depend on your sub. WinISD is pretty good. It gives you a lot of variables to play with in calculating, just be ready to convert. Quote Link to comment Share on other sites More sharing options...
dcofer Posted November 27, 2011 Author Report Share Posted November 27, 2011 Actually just graduated in May haha, did electrical engineering. matlab is a great tool, cant edit quite as easily as say excel but I know how to grid out equations and graphs in it better. I could get a super flat response with 2:1 sealed:ported with the t/s parameters I had availible, anything else seemed to have a distorted curve. I havent used winisd in a long time, Ill have to look into it again and see how the numbers compare. Yeah I knew they tend to be more spl oriented enlosures but since ive never made one I thought it would be a fun project, plus I enjoy figuring out the math behind the build haha, its nice to plug it in and visualize the ideal response of the system. thanks Quote Link to comment Share on other sites More sharing options...
AmericanLegend Posted November 27, 2011 Report Share Posted November 27, 2011 You're being lazy lol. You're asking questions that you certainly know how to figure out on your own. It sounds like you know what you're getting into, so good luck! Quote Link to comment Share on other sites More sharing options...
dcofer Posted November 27, 2011 Author Report Share Posted November 27, 2011 (edited) Its one of those situations where you just gotta talk it through, and everyone I have to verbalize my thoughts to around me would look at me with an empty expression and no understanding haha Guss I should just grab a beer and break out the spare MDF I have laying around and just build it and let the trial and error begin EDIT: also winisd lets you change units now, you just click on the unit image next to the box and it cycles Edited November 27, 2011 by dcofer Quote Link to comment Share on other sites More sharing options...
Jd1102 Posted November 27, 2011 Report Share Posted November 27, 2011 i have a question i thought that the flattest response was 2:1 ported:sealed?????? Quote Link to comment Share on other sites More sharing options...
6berry Posted November 27, 2011 Report Share Posted November 27, 2011 You always go with more ported than sealed. Some people go 1:1.5ish sealed:ported. Some people go as much as 1:3 sealed:ported. Tuning is normally between 40-60. Bigger sealed is more efficient, smaller sealed is more power handling. More ported is peakier output, smaller ported is more bandwidth. That's all I can think of right now Quote 1999 Audi A4 1.8T::: 4 - DC Level 3 10's in a 4th order Rockford P6002 on Subs for now (3-3.5k coming eventually) MB Quart ONX4.60 for Mids and Highs Boston S50 Components in Front Boston S65 Coaxials in Rear 40 Sq Ft of Second Skin Damplifier Build Thread UBL 1948 Plymouth Link to comment Share on other sites More sharing options...
Jd1102 Posted November 27, 2011 Report Share Posted November 27, 2011 You always go with more ported than sealed. Some people go 1:1.5ish sealed:ported. Some people go as much as 1:3 sealed:ported. Tuning is normally between 40-60. Bigger sealed is more efficient, smaller sealed is more power handling. More ported is peakier output, smaller ported is more bandwidth. That's all I can think of right now thank you that is useful!!!! Quote Link to comment Share on other sites More sharing options...
Ray Posted November 27, 2011 Report Share Posted November 27, 2011 I like .5sealed and 1.2 ported tuned to 41 with 14sqin per Quote 2008 California state record holder 157.2 Bassrace2009 California state record holder 157.0 BassraceRollin 50's 158.7db2009 King of Cali Bassrace2009 USACi score 160.5 @ 42hz Link to comment Share on other sites More sharing options...
Jd1102 Posted November 27, 2011 Report Share Posted November 27, 2011 I like .5sealed and 1.2 ported tuned to 41 with 14sqin per id listen to anything this man suggests Quote Link to comment Share on other sites More sharing options...
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