JL Sub trouble

[JDoggHSTX 10+ year member]

Ok. ive got 3 JL Audio 12w3's in a truck box. they are running off a Lanzar Vibe 1200D mono amplifier. ive got it wired so that the amp recieves a 1.5 ohm load. the outside 2 subs are wired in series, and the middle one is in parallel. i have 4 ga. power wire and 12 ga. speaker wire. the wires are spliced as soon as they enter the box. when i have a song w/ lots of bass in, and turn it up, the middle sub makes a horrible noise. i dont think it is bottoming out, but maybe overextending. what could be causing this, and what can i do to fix it?

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[billetz23 10+ year member]

jdogg hstx- what are the 2 outside sub

voice coils rated at (2 ohm, 4 ohm, or 6 ohm

voice coils

also what is the middle sub voice coils

rated at (2 ohm, 4 ohm, or 6 ohm voice coils

 

[ramos 5,000+ posts]

Let's see here. You have 3 4ohm dvc two of which are wired in series, the other parallel.

The way the subs are currently wired the subs will not get equal power. The middle sub could very well be overdriven. How are the drivers connected to each other?

My suggestion would be to wire the subs individualy in series. So each sub would be 8ohm. Now parallel all three subs. You will end up with roughly a little over a 2ohm mono load. Try it like this and see if the middle sub still makes the horrible noise. And if the holes you described aren't sealed completly already. Get some silicon and seal them up.

[ 01-02-2002: Message edited by: ramos ]

 

[JDoggHSTX 10+ year member]

ok. the subs are dual 4ohm. the holes are sealed up now. the specs for the amp are 1200w @ 1.3 ohms, 700w @ 2ohms, and 400w at 4ohms. so, if i wire it up like you are saying, i will have a load of 2+ ohms. therefore, the subs will only be getting about 225w apiece. they are rated at 250rms, but i have always heard that they work better at around 300w. should i just wire 2 subs up in parallel to give it a 2.7 load and then but another amp for the other sub?

 

[billetz23 10+ year member]

jdogghstx-you will be better of wiring your

3 jl 12w3 as recommended so your amp sees a 2+

mono load. save your money and just use the

1200. what kind of truck box do you have the

12w3 in. is it factory made(by who) or did you

build it you self. if you did then what is the

spec for the (hight,width,lenth.) for example

7"width at top

10"width at bottom

14"hight/length

these spec are just an example (for one subwoofer)

 

[JDoggHSTX 10+ year member]

the box was "custom" built by the guy that installed the system. it is 59 in. long, 19.5 in tall, and 7 in wide at the top(i dont know the bottom measurement but it is wider than the top) it is just one long box divided into 3 seperate compartments. i figured the volume to be a little over 1.5cu ft. per compartment, but i might be wrong., also, the middle sub is pressed against the back of the flipdown console, so it doesn't have as much space in front of it as the other 2.

 

[JDoggHSTX 10+ year member]

the amp is 700w at 2 ohms, that would give it a 2.7 load, so i wouldn't be getting hardly any power to the subs. what should i do?

 

[billetz23 10+ year member]

jdogghstx--did you wire you subs into a 2.67 ohm

load to your amp did the middle sub still make

those strange noises try moving your seat all

the way forward so your seat dosent block the

output of your subs how does it sound with the seat forward then try moving your seat back to just where your able to drive maybe 1 or 2 clicks before max so you seat is not pressing up

on you subs what is the setting(gain) at for your amp

 

[JDoggHSTX 10+ year member]

i havent had a chance to rewire the sub yet; i plan on doing that this afternoon. as for the seat though, it doesnt move. the only way to move it forward is to drill new holes, and then i would have to have them threaded for the screws that hold it in place.

 

[billetz23 10+ year member]

jdogghstx-- so your front seat dosent have a slider to move

it front to back ( if it dosent then just leave the seat alone)

try wiring the subs into a 2.67 load and see how it sounds

 

[JDoggHSTX 10+ year member]

ok. im going to do that right now. ill get back to you l8er

 

[JDoggHSTX 10+ year member]

ok. i rewired the sub this afternoon. it sounds good but it is not as loud. at least my headlights dont dim anymore though.

 

[mrray13 10+ year member]

just a word of caution; make sure your console isn't all the way up against your middle sub(as to seal it). if it is it could (possibly) trash it. i've ruined two seats of tens under the back seat of my quad cab. they were pressed all the way against the seat when it was down. the shop said because the subs couldn't throw forward it overheated (overexurted, i can't remember which) the voice coils! eek:

 

[ramos 5,000+ posts]

Originally posted by JDoggHSTX ok. i rewired the sub this afternoon. it sounds good but it is not as loud. at least my headlights dont dim anymore though.

So you don't here the distortion anymore ? It was do to the way you had your subs wired at different impedences. The subs were not getting equal power.