NotEnoughBass Posted January 4, 2012 Report Posted January 4, 2012 So sorry if im jacking the thread but would 10" in per cube for two 18s on 1.5k be too small? 1998 Jeep Cherokee Alpine HU Crunch Powerone 300.2 mid/highs + AP15001D bass Soon to be two OA18s Cadence coax and sony tweets Big three + All 1/0 wire Optima Yellow Top No hating on my ghetto system plz. (Im poor)
dragonsage2008 Posted January 4, 2012 Report Posted January 4, 2012 if i where u i would move the port to the left or right side of the box then... top back
carshateme Posted January 4, 2012 Author Report Posted January 4, 2012 if i where u i would move the port to the left or right side of the box then... Wheel Well in the way. New build coming soon. [center][url="http://imageshack.us/photo/my-images/3/sigtoo.jpg/"][img]http://img3.imageshack.us/img3/9541/sigtoo.jpg[/img][/url][/center]
bdog Posted January 4, 2012 Report Posted January 4, 2012 you can put a 2 inch port along the top or bottom of the subs and still have 1.5 per woofer REP
bkolfo4 Posted January 4, 2012 Report Posted January 4, 2012 I was not referring to your subs as cheap-o, but was trying to explain with an example that port area is not related to box volume. 12-16 sqin per cuft is a very gross approximation that has somehow become a law to many people. Port area is based on air velocity through the port which comes from the amount of air volume the subs can sweep through their max excursion along with the port tuning frequency. Current system: 1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s Previous systems: 2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz. 1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz.
Joe X Posted January 4, 2012 Report Posted January 4, 2012 I was not referring to your subs as cheap-o, but was trying to explain with an example that port area is not related to box volume. 12-16 sqin per cuft is a very gross approximation that has somehow become a law to many people. Port area is based on air velocity through the port which comes from the amount of air volume the subs can sweep through their max excursion along with the port tuning frequency. If you have the time check vent airspeed by modelling software and you will see that the recommendation leads to very reasonable results without many calculations PROVIDED that the box volume is chosen correctly for the sub you intend to use, if the sub is high excursion you can lean towards 16. Richard Small's estimate which is effectively related to the subwoofer displacement leads to larger port sizes so if nothing else it's a good idea to follow the recommendation. For those curious about Richard Small's estimate: Vd = Sd*xmax Dmin >= (Fb*Vd)^0.5 (minimum diameter of vent)
bkolfo4 Posted January 5, 2012 Report Posted January 5, 2012 But using the volume based calculation can be misleading. If I run a sub in a larger box because I have low power, the Vb theory says I need more port area compared to running that same driver in a smaller box with very high power, when the opposite is really true. I know the 12-16 normally runs sufficient, but it is a wide range the larger the box gets, and there are just so many exceptions that I like to rant every time I see it. . . Current system: 1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s Previous systems: 2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz. 1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz.
carshateme Posted January 5, 2012 Author Report Posted January 5, 2012 Ah well, I already started on it and it's already cut out.. New build coming soon. [center][url="http://imageshack.us/photo/my-images/3/sigtoo.jpg/"][img]http://img3.imageshack.us/img3/9541/sigtoo.jpg[/img][/url][/center]
Joe X Posted January 5, 2012 Report Posted January 5, 2012 Ah well, I already started on it and it's already cut out.. Sort of a shame since aero ports could also be considered, much better sound quality results than that slot.
dragonsage2008 Posted January 5, 2012 Report Posted January 5, 2012 wheel wall or not as long as u would of had about 2-4 inches of space would of been better to put the port on the side... top back
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