has anyone tried a box with a down firing port in there truck. im about to build a new box and i was trying to figure out which way to face the port. its not an under seat box, i made the back seat where i can put a box in between them but im not happy with what i have now so im gonna try a different sub. ive tried facing ports in every other direction, front or back sounds the best, to the side sounds about the same but not quite as loud, and facing up just sounds like crap to me. the idea i had was having the sub facing the rear wall and have a slot port going down the front side and stop it a few inches above the floor. i know some HT systems use a down firing port but im just not sure what it will sound like in a vehicle. also with the box side of the port going all the way to the floor and the outer side stopping short, would that affect the sound?

thanks,
Corey

 

port and sub facing up = best spl on the mic

 

that may be true. i havent metered mine with it facing up so ill try that tomorrow. right now i have the sub and port facing the back and i get the highest spl when both windows are down but anytime ive put it in there with the port facing the roof i lose all low end bass, but maybe if i roll the windows up it will change that. another thing that may have been a factor was a lack of sound deadening on the roof, which i have now.

 

mine is port and subs facing back wall right now and it hits noticeably harder than it did when i had it facing up but i like they way both of them sound, i noticed my lows hit a little better facing towards the rear wall

 

ok i wasnt doing anything tonight so i went ahead and tried it facing up. i had my amp set at 3/4 gain, facing the back wall i got 146 db at 40 hz, facing up i got 137 db at 45 hz. your setup may be a lot different than mine but ive tried several different things in my truck and really havent been able to get the sound im looking for yet. my friend had an 01 celica with 2 12's in the back facing up and a 500 watt amp pushing them and honestly thats the best sounding 12's ive ever heard. i took it out of his car one time and put it in my truck and it sounded horrible lol. the sub i have now is an orion hcca 12.2 in a 2 cu.ft. box tuned to 38 hz (per manufacturers specs). the one im gonna put in is a phoenix gold titanium elite 12d and im gonna put it in a 3.5 cu.ft. box tuned to 18 hz (per winisd). if i can get in the 130's and still hit 20 hz nice and clean then ill be happy. im not goin for a competition system, just something that sounds good and still gets loud.

 

where are you putting the mic? windows down is always going to be louder than up

try it again but with the same frequency

 

You also need to tune the box to the vehicle for maximum SPL. I'm 99% sure you have not done that. Correct?

 

i got an audio control epic 160 with an spl meter and mic on it, its underneath the cd player. im sure its not spot on accurate (i only paid a couple hundred for it) but i plan on checking it against one at a local shop here. ill find out what brand his is too because he told me he paid like 3K for it but im not sure if i believe that. and no i havent tried tuning specifically for my truck because i really dont know how. im tryin to learn as much as i can but with all my past stuff its been basic trial and error, mostly error lol. but like i said earlier im really not goin for maximum spl say in the 50's and 60's. id rather have mine louder below 40 hz and feel the truck shaking to pieces on the low notes, if the sub can handle it that is. heres a pic with the meter, not a good one but its all i have.

 

hopefully the guy has a termlab. you'll know it when you see it it suction cups to the windshield on the passenger side I can get the measurements to the exact spot if you need them

 

yea i went there before and got him to check mine and his meter was showing 140db but i cant remember what frequency.i had a different box and amp back then though but my meter was reading 142 with the new amp and old box. i know term lab is what they use in competition but i dont think thats what he has. its similar with the suction cup mic but it wasnt a pc software, i believe i found it on google. its also made by audio control but it is actual professional equipment.

 

Typical of CRX style enclosures but the port is still rear firing, rear-facing is usually louder in a hatch though, keep in mind the acoustics of our trucks, and also resonant freq is a bit higher in this environment than in other vehicle styles.