Vehicle : 1973 VW Beetle Location in the vehicle: Rear cargo area; sub pointed up Space available (Length x Width x Height): 35" length x 12" depth x 12-15" height Subwoofer make and model: Fi SSD Subwoofer Size: 10 Number of Subwoofers: 1 Type of Port (Kerfed, Slot, Aero, etc.): Rectangle w/ 45's What type of music do you like?: EDM, RAP, Rock, Is your goal SPL or Everyday Music?: Everyday high sq Tuning Freq (Hz): 35 - 38hz? Volume : 1 - 1.5? Questions: So I have modeled up a few different enclosure in win isd but I just want some confirmation as to what you guys think will work best for my listening needs. From what I have read on this forum that I believe Fi recommends a tuning between 31-35hz and 1.5 cu ft. Modeled the box up they suggest and some of the numbers in win isd don't seem to comply with recommendations I find online, for ex. port velocity seems way too high ~ 130ft/s and output seems to lack around the 40-50hz region. From what I understand it seems as though when designing a box in a small vehicle such as my VW you can go a little bit higher due to cabin gain if I understand correctly. After modeling it seems as though 1-1.25 cu ft and a tuning of 38hz seems to produce a nice curve that also had minimal group delay and won't produce a ridiculous peak in output. My question is are there any other suggestion as to maybe more box volume or less and will there be any unforeseen issues with tuning to 38hz instead of 35? Also can someone give me any insight on how tuning affects subs ability to play in the 60-100 hz region? If I understand correctly tuning lower limits the sub woofers ability to play the higher notes?