View Full Version : Port noise????

12-16-2012, 11:10 PM
Vehicle : 2011 Jeep Grand Cherokee
Location in the vehicle: Cargo
Space available (Length x Width x Height): Max box dimensions 36x16x16
Subwoofer make and model: JL Audio W3V3
Subwoofer Size: 12 inch
Number of Subwoofers: 2
Type of Port (Kerfed, Slot, Aero, etc.): Sloted
What type of music do you like?: everything
Is your goal SPL or Everyday Music?: 50/50
Tuning Freq (Hz): 30 Hz
Volume : approx 1.75 cu ft per sub

I am planning a box split into two chambers that are 18.375x16x16.5 sealed from each other and slot ported individually. To get it tuned to 29.96hz i had to go with a port measuring 1.25x14.5x27.5. net internal volume after speaker and port displacement = apx 1.75 ft^3

i cant get drivers to save in winisd so what im wondering is if i will have any port noise with this being almost 1:11 port ratio?

Any say??

12-17-2012, 02:12 PM
Having designed a million boxes using that program I would say that you would definitely get a graph above 65 ft/s, which is kind of the rule of thumb for port noise. Plus with such a large ratio you are introducing other issues. I know you are likely keeping the post thin to minimize length of the port but you will def want to go at least 2 inches wide, if not 3. This will result in a larger port, but lower air port velocity.