tuning my system

Im an installer an even I feel stupid for asking this but here i go. I have a 2003 quad cab dodge ram an i cut the center seat out an have installed a 6 cu ft box that houses an MTX 9500 DVC 4 ohm sub. I have an MTX 1501D mono amp powering it with I have a PAC audio turbo X line driver in line. this system has been a killin me for about 3 months now I cant seem to get it sounding right any suggestionsNick Miller

Vented system?  Tuned to what frequency?Support the12volt.com

yes its a vented box tuned to 33hzNick Miller

Can you post a pic of the enclosure? I'll eat my words if you have the gross 6ft3. It'd be worth it for me to see though;)This is what I do for FUN!

the box is 16" tall, 18" wide, an 33" long I built it when i attened the installer institute an it came out to b 6 cu ft. I have a feeling the box is way to big for the sub an thats y im having a hard time tuning it. Is there mabye something i can use to pack in the box to take up some of the air space.Nick Miller

16X18X33, assuming you used 3/4" MDF, nets a 4.4 cuft enclosure, which is actually a little smaller than optimum for a Thunder 9500.  If you built the port targeting 33Hz in a 6 cuft enclosure, your actual tuning frequency is more like 38Hz.  Not a huge difference but it means you will have several db less output in the lowest octave from the system and a higher tuning will mean more "boom" in the cabin,Support the12volt.com

u knw u might be right about it being 4.4 cu ft, cuz when i was desiging it i was going for 6 cu ft but my instructor did kinda copy the dimensions of the box i used to have. any way the way its tuned when im playing a cd,dvd or ipod some songs are louder then others bass wise. would it jus be the songs or the actual tuning its self cuz if its jus the songs then i jus wasted the past 3 months trying to tune this system for no reason.Nick Miller

If it sounds good on one song but not on another, then it's the song you're using.  Use test tones and an RTA if you want to know what the system is doing.Support the12volt.com

thats kinda what i figured, I guess it is time to break out the RTA, I did upgrade my Pac audio turbo x line driver yesterday to the planet audio PLD-2 2 ch line driver would that make any difference to my setup compared to the PACNick Miller

I hate RTA's! A device that has no business taking readings in a vehicle! When you mention "tuning" are you talking just the sub? MTX has come a long way, but their speakers are not going to be the ones that will deliver everything you could of ever wanted. In the cab- with the sub in the center of the vehicle, the downfire, sealed enclosure has made many enthusiasts happy with the sound.   With that sub sitting so close to the ear, the sound waves coming directly from it will disturb the ears listening ability.(A judgement I'd theorize) To me, it seems as if your ears are what is seeking satisfaction, and to appease them, a 10" sub might have better luck. If not, the config that delivers is to fire the sub forward and the vent fire right above or below it. When using this setup, the sound can curl up in the front of the truck and peel back toward the face taking in a blend with front stage. The RTA will notice the delay that the sub has in this config but your ears might appreciate it more.This is what I do for FUN!