advice from the spl guru's

[grandam888 10+ year member]

right now i am hitting a 144 @ the dash and 150.4 @ port. i feel i could gain a few decibels.

my current system is is in sig.

right now port and speaker are facing roof, someone explained to me if port and speaker were to face hatch instead i would gain a decibel or two do to the sound waves being able to move to the the front of the cab better. so i will be doing that this week.

also, my roof has MASSIVE flex right above port, port is less than 2 feet from ceiling, roof actually starts doing a waving movement on certain tones. and roof flexes rough 2-4 inches @ times in front of cabin. so also this weekend will be bracing roof, and adding sound deaden er when funds allow.

just wanted to know if i may be moving in the right direction as i am new to spl, and what else i could do to improve my numbers without adding more equipment. i am about maxed out equipment wise(not much more room available).

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[sacsking916 5,000+ posts]

try both back, and both forward. im assuming you dont have a meter to test everytime you move the box?

and what kinda car is it? cause you should be doing a better number than that IMO

 

[grandam888 10+ year member]

no i don't own a meter, but live 30 minutes away from a shop that will allow me to go in and do what i want and doesn't charge me for meter time.

im confused as i look @ scores from people with less equipment /power than me and hitting higher numbers.

 

[sacsking916 5,000+ posts]

im capable of doing a bigger number than that with my 12 bro. not hatin or talkin smack but it just seems your number should be higher. if your able to i would say try port/sub forward and back while your at the shop to test out which is louder. is it for music or for burps?

 

[05fronty 5,000+ posts]

just move stuff around. is that number sealed on the dash? door open,etc?

 

[Bettr n' Revrse 5,000+ posts]

Ya a 144? that seems low for a BTL 18 cuz Im pretty sure I could do that with my 12 as well...

 

[grandam888 10+ year member]

ive tried both burps and music, get better results on a sweeping tone from about 60hz to 30hz. and no pun taken, i felt my numbers weren't right. maybe his meter is messed up cause i saw him abusing it a bit.

and i will try and get back down there this week and try out moving the box around.

 

---------- Post added at 07:15 PM ---------- Previous post was at 07:14 PM ----------

 

also number is sealed on dash, and in port was with car sealed also(may not be relevant?)

 

[nateberrier 10+ year member]

depends what car but in hatches i usually go sub up port back or sub forward port up. depends on the car and the frequency. there is a guy doing 139s with a single 12 in a pt cruiser on 300rms. sub and port back. but it depends. trunks i have seen sub side port back and sub up port side do well.

 

[grandam888 10+ year member]

ive been reading up, and see that if a person doesn't know what they were doing the term lab could be way off due to not being calibrated correctly.

but i will try to move my box port back sub back as thats the easiest to do right now.

 

[stevew007 10+ year member]

few things i see that i see that might hurt.

8cf box for 1 18" (i have 4 15's in a 8cf box)all spl and its going to get smaller

hc800? is that the only battery you have?

what are 2 runs of wire? power/power power/grond?

what load do you have on that 2400? you might have a big box rise!

in your sig it says termpro and then you talk about termlab? what one is it?

also the termlab does not need calibrated you can only adjust the k-factor and they are set real close from factory.

also what kind of vehicle is it??

 

[Kangaroux 5,000+ posts]

yeah 8 cubes is prob too much. you want a bigger box to help hit the lows but when it comes to SPL you want a smaller box since you're concerned about higher frequencies...what is your box tuned to?

 

[grandam888 10+ year member]

first i believe termpro makes termalb. its a termlab meter. i saw it in person.

secondly, hc800 is the only battery i have aside from battery underhood. i do watch my voltage VERY colsely and it NEVER drop below 13, usually stays around 13.5.

also my amp is running with a load of .7 ohms before any rise. i have no idea what it rises to during play.

my 2 runs of wire are 1/0 wire from battery to hc800 in back, then a single ground about 2 feet from that battery. my voltages are pretty stable.

vehicle is 2000 jeep cherokee, sub and ported pointed directly towards ceiling.

also have a 250amp alternator and box is tuned to 35hz

 

[grandam888 10+ year member]

also running 16 inches of port area per cubic ft of box volume

 

[stevew007 10+ year member]

first i believe termpro makes termalb. its a termlab meter. i saw it in person.
secondly, hc800 is the only battery i have aside from battery underhood. i do watch my voltage VERY colsely and it NEVER drop below 13, usually stays around 13.5.

also my amp is running with a load of .7 ohms before any rise. i have no idea what it rises to during play.

my 2 runs of wire are 1/0 wire from battery to hc800 in back, then a single ground about 2 feet from that battery. my voltages are pretty stable.

vehicle is 2000 jeep cherokee, sub and ported pointed directly towards ceiling.

also have a 250amp alternator and box is tuned to 35hz

well im old and have had a termpro before the termlab thats why i asked.

anyways sub up ports back use some 6" aeros external mounted if you have the money. make a new box about 2cf after displacment. my guess would be that your best score was around 50hrtz? if i was you i wouldent waste your time on facing the subs and port back. it might be a gain but not as good as the box I'm telling you to build.you know what 1/4 wave therory is right? well thats kind of the reason behind the subs up port back

 

[grandam888 10+ year member]

did i read 2cf? thats really small, not that i think your wrong, but i am just surprised. also as of right now, no money for aero ports, poured all money into equipment. and i have no idea what 1/4 wave port therory is.