88pro2 Posted December 30, 2012 Report Posted December 30, 2012 I have multiple subs and sizes from different brands and have noticed a common thing. The manufacturers recommended box size and port size and length for tune they give, do not match the port diameter min. size requirements that the calculation programs are giving me. WHY? Actually the 2 brands I have and one other I have looked at, recommend roughly about 1/2 port size of what the computer programs are telling me I need for correct port volume to not have port noise. Do the factories not care about port noise? Are they using the smaller port area to help control the cone better? They based their recommendations off actual use boxes not a generated box program. Do I lean toward their recommendations for port sizing or go toward the program recommendations? Any thoughts? Current system: Front--Focal 165k2p components Rear---Polk Momo 5x7 rear fill Front amp--Rockford Fosgate Power 650 w/4" fan bridged @ 372.49w x 2(poor Focals) Rear amp--Phoenix Gold ti400.2 @ 100w x 2 Subs--2 Image Dynamics IDQ12D2V.2 @ 1cu.ft. each sealed Sub amps--2 Phoenix Gold ti800.1 @ 800w+ one for each woofer(poor ID's) head unit--Alpine 7292s vintage 1990's Eq--Alpine ERE-G180 Cd changer--Alpine 5960 6 disc also vintage 1990's Alumapro 5fd cap dual 1000cca batteries ho 200amp alt. No need to clip it because of the headroom I have with the power. Dang spider wire broke on the Focal when glue came off the cone. Time to redo! This is a std cab truck!! System is changing soon!! Looking to do a 3 way setup up front, and may double that up, to get the volume. Also have 2 Orion HCCA15d early vintage and 3 Orion XTR2250 on hand. Looking for Audison VRX, LRX or Zapco c2k to possibly add in.
john253a Posted December 30, 2012 Report Posted December 30, 2012 First idd say your reading the program wrong What program is it Secondly no one would buy(except bass head like us) if they what the real size the box should be Most mainfactors do aero ports at 7sq per ft and slot at 12sq per ft tuned to 37-42 Hz because the box is a more usable size for the average car and person You must remember we(here) are the minority of people buying main stem stuff and filling the entire trunk Most are happy to use a small part of trunk for just some extra bum
Nightshade Posted December 30, 2012 Report Posted December 30, 2012 I don't ever go off manufacturer specs. I go off woofer size and what type of output you are looking for. Usually for me enclosures I always use aeroports and stay at 8-12 sqin of port per cuft of box area. This is good for SPL and a fairly nice frequency roll off. For pure SPL the port area is increased anywhere from 12-24 sqin of port per cuft. This is where I've done my best SPL numbers at. I don't really ever build slot port boxes but from my little experience with them usually 25-50% more port area than an aero port is a good rule of thumb. 2013 VW Jetta GLI 2.0 Turbo 1 Sundown Audio SCV2000 1 Sundown Audio X15 V2 1 XS Power D3100 Audio Control LC6i Stock Deck 146.4 sealed on the dash at 37hz 2001 Focus ZX3: RETIRED Team Sundown Audio, Team XS Power, 2 time NSPL Car 3601-Up Champion, 2 time NSPL Car Hardcore ChampionHighest NSPL Scores to date:154.3db on the dash sealed at 46hz, 156.2db in the kick at 46hz155.2db unofficial on dash at 43hz
Guest Posted December 30, 2012 Report Posted December 30, 2012 for me, it goes: other peoples proven-tested specs, manufacturer, then box programs.
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