re audio sl12 port size?

I have an RE SL12 that has been sitting in my garage that I found a use for but there's no paperwork inside the box. I've made the mold for it and spreading it across under the entire rear bench seat I shouldn't have a problem getting 1.25-1.5 cu ft but how do I tune it to 35 hz like they recommend? I'm sure there was paperwork in the box at some point but who knows what I did with it and now I'm lost. here's the specs in text format Mounting Depth - 3.5" Mounting Hole Diameter - 11" Overall Diameter - 13" Bolt Hole Circle - 11.75" Motor Width - 4" Motor Depth - 0.12" Basket Depth - 3.5" Displacement - 0.10 cu. ft. Weight - 15.5 lbs. Electrical Q Value -Qes: 0.56 Mechanical Q Value -Qms: 3.69 Total Speaker Q Value -Qts: 0.48 Free Air Resonance -Fs: 32.0 Hz Equivalent Compliance -Vas: 51 liters One-Way, Linear Excursion -Xmax: 16 mm Efficiency -SPL 1W/1m: 86.8 dB SPL Effective Piston Area -Sd: 470 cm^2 DC Resistance -Re: 3.5 ohm Nominal Impedance -Znom: Dual 4 ohm Thermal Power Handling -Pe: 350 W Force Factor -Bl: 19.53 I hope somebody has this sub and knows or there's a way to figure out what to do based on the numbers. Thank you everybody for your help

Use the port length calculator in the links on the left column. Enter your enclosure volume, the size port you want to use and desired tuning frequency.Support the12volt.com

wow, I feel like an idiot. It's really that simple? haha. I'm so sorry, I'm so used to just building the box how the manuals say without really understanding how they got those numbers. Thanks for not making me feel like a total moron even though I obviously am !

You're not a moron. When you have questions, ask! I'm glad the answer was easy. :)Support the12volt.com