? for Matt

Hello team spead members. My name is Joel Fisher. I live in McComb Miss. I am 33 years old and have been playing with car audio since about 1989. I competed heavy in 94 and 95 with support from Richard Hale and Sound Advice, in Baton Rouge. I also have family in Gonzalez. I am currently back in college to become an RN, and have gotten interested in competing again in the street beat stuff. I come from the old school when we built a wall and shoved as many woofers in as you could fit sealed.
I currently have a 94 ex-cab chevy with no rear seat. We have two 15" Massive CW woofers running off of a single 1500.1D Massive pro amp. one extra red top Optima near the amp.
The current enclosure I have had in the truck for about a year. It is around 9.2-9.5 cub.ft. (61x16x18.75) with a 14.5H X 5W x 18L port. According to bassbox its tuned to 30hz. I designed this enclosure with help from Massive tech guys. the enclosure SOUNDS awesome very musical and fast attack for a ported enclosure. We have ran the truck twice in the last few weeks at Iron Hourse and Presley Audio and consistantly did 142dB in SB3 class, and the truck has done 146.6dB @ 38hz! outlaw Its a real ground pounder but this setup does not do much on the meter. So, we decided to pull the box (WHICH I KEPT SHES TUCKED AWAY IN THE CORNER OF THE SHOP!) and test tweek and build. I figured 1/4 wave, transfer function, talked to others, the whole nine yards. we ended up building a new enclosure 58x22x16 with a 14.5 x 12 x 3 slot port tuned to 51hz. fired the woofers and ports up (old box both fired forward).. the results.. I lost about 2dB. It does 144.4 at 58hz now. SIGH! well i re tuned the port to 14.5 x 10 x 9 to the tune of 43hz. and thats where we stopped for the day...we have not put this setup on the TL but it feels much stronger than the 51hz tune.
Matt, I liked the way it sounded before, but I figured if we could rebuild a similar box and tune a high spl slot port that kicked ass for street beat, we could drop a cover plate on the slot and tune two 4" aero ports back down to 30hz and have my cake and eat it too. problem is so far I am not having any luck getting more pressure than the box that sounds great. I plan on putting it on the TL tomorrow at 43hz and see what we get, but I about fed up, and with this truck I dont have alot of room for moving the enclosure walls for tuning to keep it under the back glass. hell I guess I should not have bitched She has won two first in SB3 so far, but Miss has less support for sb class. you guys have some heavy hitters in La playing in the sb classes. Hell I just want to keep up at this point.
So after hearing me ramble if you guys have any ideas or see something I am doing totally wrong please feel free to tell me how stupid I am being. Like I said I know old school, when ported boxes where in the SQ cars and spl vehicles had 16 15's.
Any input would be appriciated, figured I would ask you guys in S.P.E.A.D. you all seem to be strong competitors, and I will see you guys at Scrappin the coast if I dont have to work.

With SPL boxes I find that unless you have a van with a lot of depth the extremely large box sizes are useless, as well as the quarter wave theory. Cone control is extremely important and I prefer smaller enclosures. The enclosure volume will actually dictate your peak frequency moreso than the port area and tuning will. My current enclosures in my CRX play 61hz no matter if I use a 6'' port per sub or a 4'' port per sub, no matter if the ports are 24'' long or 5'' long, however the score changed as much as +/-6dB from where everything works together and where it obviously doesn't.

Its not just the enclosure, its the car, the subs, box, power, frequency, and quality of power that all matter. It must all work together to be loud. Thats probably the best tip I can give you. If you can't read between the lines and pick out the useful info from that then feel free to come down to BR and I will build/tune your truck.

_________________
Matt Sibley, BSEE, EIT
Team S.P.E.A.D. Captain

yeah, Pat Day of presely told me I may want to play with a smaller encosure. Thanks for your time and the response. I understand this is how you make your money and again appricate any pointers. I will see what I can do with it, either way I will see you guys this summer. once you get the itch for this crap you start just showing up at all the shows.. lol later, and good luck this season to your team.