JBL gti 12 inch please read

[customlt1 10+ year member]

Okay so about a month ago i got a jbl gti 12 inch strait from an authorized dealer....i put it in a 1.00 sealed box but it was slanted so it was way to small...the sub sounded like garbage in it..when you would turn it up decently it would make a weird popping sound almost like the sub was blown....so i then put the sub into a 1.25 slanted sealed box but still the same problem..so i took the sub back to the store and they got me a BRAND NEW one..went back into that 1.25 inch and still didn't sound right..so at this point i was thinking its the box...so i had my dad (hes a awesome box builder) build me to spec a 2.25 cubic foot ported box....EXACTLY to jbl specs for this sub....The sub is now in and i took it back to the store to get tuned.....Im not sure what its tuned too but i know the gains are very low....the sub bumps but not nearly as loud as it should....if i turn the gains up on the amp the sub gets MUCH louder but than again i hear that popping noise like the sub is blown..at this point i don't know what to do....the only reason i don't think its as loud as it should is bc i had an alpine x-type which is a VERY close comparison and i had that in a tiny 1.00 sealed box and that thing banged 10 times as loud as this jbl....well any help with this matter will be MUCH appreciated...thanks

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[Steven Kephart 10+ year member]

What type of amp are you using? It sounds like you need more power. BTW, what you are probably hearing is the amplifier clipping which can sound very mechanical.

 

[customlt1 10+ year member]

jbl 1200.1 monoblock

 

[negativezeroz 5,000+ posts]

My W10GTi slammed off my GTO601.1 (~550ish RMS at 3ohm) in a 1.75ft^3 tuned at 27Hz. Your 12 should be loud and sound clean using that BP and in 2.25ft^3 tuned to near 27-33Hz

 

[customlt1 10+ year member]

so if i leave my gains up it should sound fine?

 

[negativezeroz 5,000+ posts]

find out what the box is tuned to, my gains on almost all the way down and my W10GTi hit hard

 

[customlt1 10+ year member]

so if you turn your gains up will you speaker distort like mine?

 

[negativezeroz 5,000+ posts]

mine didnt distort at any level which I played it at....I dont have any it more. UPS destroyed it.

What HU, wiring, car, etc do you have? Just throw out all the info you can so I can help.

 

[Steven Kephart 10+ year member]

jbl 1200.1 monoblock

Ah, that explains it. Are the pre-amp outputs on your head unit 4 volts or higher? If so then the gain on the amplifier needs to be turned down all the way otherwise it will clip the signal.

 

[customlt1 10+ year member]

i have a 99 jeep grand cherokee with a 12'' jbl gti in a 2.25 ported box 3/4 mdf....wiring is 4 guage and the headunit is a sony xav-7w flipout with a blankrupt dvd player....

 

[RADEoN 10+ year member]

I run 3 W10GTi's off of 2 BP1200.1's, and I must admit that I hear the noise you're talking about occasionally.

What I've come to learn, is that the subwoofer will be fine playing a slightly clipped signal. I mean SLIGHTLY. The BP1200 does in fact do around 1000 watts at 3 ohms. It's an underrated amplifier. Your best bet to avoid that noise is to turn the LPF to around 1/4 of the way up, and use very very little, if any bass boost.

By the way, what are the box dimensions and port measurements?

 

[Warbleed 10+ year member]

IMO, bass boost should always be OFF. You might as well call it distortion boost...

 

[ihatejlaudio 10+ year member]

I have 2 gtis off of a bp 2200.1 in a dual vented enclosure and i have never had a problem with my subs sounding well.. My buddy has 1 in a 2.27 cube box in his new stratus on an older bp 1200.1 gettin sgnal from his avicN1 ( about 2volts from the preouts) and have never heard a problem from his either.. those are great subs so i hope that u get the problem fixed so u can enjoy them to the fullest.//content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif

 

[negativezeroz 5,000+ posts]

Not necessarily. Mine is on and subs hit pretty good too....just ask the person that couldn't sit in my blzr no more than 4 sec....

coming from someone with (4) SE's....//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

just turn ur bass boost like off man..seriously...

 

[customlt1 10+ year member]

okay heres some more info.....

my box design is

20'' Length

16'' width

14'' height

the port is

14'' deep

12'' height

my dad made the box so im not too knowledgable on how to explain it....hes an AWESOME carpenter this box looks awesome and he knows what hes doing with the info i gave him....the dimensions came from a jbl box designer at a local sterio shop...

on the amp there are three types of settings...Input(4v-250mv),Low pass Freq. 32hz-320hz)and bass boost (0-6db)

i just tried to tune it once again and the input is basically 1/2 dial around.....i dunno what you would call that as too how much i tured it up but its about 1/4 of what it could....the low pass is a hair turned....not much AT ALL...and the bass boost is completely off as you all told me too do.....

ok the sub hits but not nearly as hard as it should....the sub barely moves most of the time but once u turn the gains up a little it starts that popping..so basically im stuck with a sub that i can't get enough potential of what it should be doing....

any help would be highly appreciated....ya'll think this could be my HU wiring or something like that? im speechless