sean 371 Posted February 1, 2007 Report Share Posted February 1, 2007 K, so here's my first bandpass design that I've done by hand (w/o winisd or another program). This is for an install we're doing in an F-250. Kind of a budget system, so hopefully we can make up for it with the box. Please just look through the numbers and tell me if this looks realistic. Hopefully I didn't eff up the math anywhere! Sub: Type S 12 Box Specs: Volume of the Ported Section: 1.05 cu ft Volume of the Sealed Section: 1.9 cu ft (is that odd that the sealed is a larger volume?) Port Specs: 50" of port, 13.88" long. Low cutoff: 26 hz High cutoff: 74 hz If I manage to get some positive replies to this, I'll go ahead and build it to see how it sounds. Thanks guys! A couple links to some box builds: Tahoe Box 1, Tahoe Box 2, Nissan Titan, VW GTI, Mini-Bump, Hummer H2, Ford F-150 My own car builds (current setup --- under construction): Overall Thread, Kickpods, Dash, Back Doors Subwoofer Wall Link to comment Share on other sites More sharing options...
LSN2meBoom916 Posted February 1, 2007 Report Share Posted February 1, 2007 Post ur math. LETs see how you got ur numbers. COOGLE SAID:"bro thats how we got where we are... buy making messes ...... i still learn all the time you just gota be willing to ruck up some shit" "In order to attain the impossible, one must attempt the absurd." ~ Miguel de Unamuno"One machine can do the work of fifty ordinary men, but no machine can do the work of one extraordinary man" -Elbert Hubbard"A proud man can learn humility...but he will be proud of that too" ~I forget who.I'm far from perfect and I know it better than anyone, but I hope to be good at what I do, when I do it...Installs I've done:My Integra: http://www.stevemeadedesigns.com/board/ind...?showtopic=3161The Lexus : http://www.stevemeadedesigns.com/board/ind...?showtopic=1535Law's Maxima: http://www.stevemeadedesigns.com/board/ind...ic=5568&hl=Jeff's 2500HD: http://www.stevemeadedesigns.com/board/ind...ic=5382&hl=Acura RSX-S: http://www.stevemeadedesigns.com/board/ind...?showtopic=3142Z-32 300zx: http://www.stevemeadedesigns.com/board/ind...?showtopic=34602004 Civic 4dr: http://www.stevemeadedesigns.com/board/ind...?showtopic=8190Trunk/Corner Box: http://www.stevemeadedesigns.com/board/ind...c=16036&hl=1969 Chevy C-10: http://www.stevemeadedesigns.com/board/ind...c=20319&hl=Seat-Back AMP-RACK How-to: http://www.stevemeadedesigns.com/board/ind...ic=9428&hl=Bunch of subs still for salehttp://www.stevemeadedesigns.com/board/ind...l=lsn2meboom916"It's game night...we're playin......sex."~Quagmire"When disneyland started it was powered completely by orphan children running on treadmills to generate e-lectrissty…and today, them children are New York Yankees". ~Dale Gribble"Fill it with ice...then pour it up to the top of the ice...& Shut da Fu** up!" ~Urs truly. Link to comment Share on other sites More sharing options...
sean 371 Posted February 1, 2007 Author Report Share Posted February 1, 2007 okay. here goes. I used .7 for my alignment (S Value), b=.7206 I picked 26 hz for my lower cutoff. (Fl) Fl' = (Fl*Qts)/Fs Fh (high cutoff) = (Fl'+*Fs/Qts (came out to 74 hz) Volume of ported chamber = (2*S*Qts)^2*Vas Volume of sealed chamber = Vas/((Qbp/Qts)^2-1) (Qbp is the Qtc of sealed chamber) Fb = Qbp*Fs/Qts (tuning frequency, came out to be 43.8 hz) For Port length I took a 4" port, which I'll convert to a slot port later. Lv = [1.463(10^7)(R^2)/(Fb^2)(Vb)] - 1.463R (R = 2 in this case) This came out to 13.88 I'm pretty sure the math is right, I'm not sure if these formulas are correct though. I took these formulas from www.diysubwoofers.org/bnd/4thord1.htm So, does this look right? As far as cutoff/tuning frequencies? Also, it seems a lil odd that the sealed chamber is larger, anything wrong there? Thanks A couple links to some box builds: Tahoe Box 1, Tahoe Box 2, Nissan Titan, VW GTI, Mini-Bump, Hummer H2, Ford F-150 My own car builds (current setup --- under construction): Overall Thread, Kickpods, Dash, Back Doors Subwoofer Wall Link to comment Share on other sites More sharing options...
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