It's actually quite simple...A mic peaks out around 60hz. Ported boxes usually peak out an octave or so above tuning frequency...making them much louder on the mic...BUT, ported boxes also lose A LOT of response below tuning.
A sealed box (larger almost allways better) will have CRAZY output on the deep notes. The low notes are closer to the natural resonant frequency of larger objects, like metal buildings, houses, sky scrapers...ect...Thus, it shakes the HELL out of them. BUT, because the mic peaks out aronud 60hz...low notes will not turn up as high a score.
With my current setup i can break 143 on the new TL mic at 29hz....even though that sounds like a crazy score for being such a low tuning frequency....its not low enough to reach the natural res. freq. of large objects around me...I had a pair of IDMAX 12" with 600 Wrms per sub in a HUGE sealed box...and if I remember correctly, they actually seemed to shake houses more violently at around 24hz (with less amplitude of course) that my current 15"s with 5000Wrms...This is because my box is tuned around 28 hz...and drops output anthing below that. Even in a box thats tuned around 20 hz, you will still not get the deep bass output like large sealed, you need to tune around 16hz in order to peak around 25hz...
I'm putting my protos in a sealed box soon enough because I'd like to tear my truck to shreds.......its got 220K on it...I need a new one...lol...why not pop the windows out of this one? lol...I seriously think I can do it sealed. (no noob talk here...) My back wall moved about 2 inches....with just the IDMAXs sealed....With these ported, I can only get it to move about an inch. Soooo...I cant wait to see what these babies do!!
Click the sig...I update it very often..so check back for some new vid of the sealed box. GONNA BE CRAZY.
