So i just won a JLIB4 off ebay and I have already installed the amp rack under the rear deck I was just wondering what my optimal gain and crossover settings should be set at? I dont know much on this stuff so any help would be greatly appreciated
thanks in advance

Here are some amp specs
RMS Power (at 12V, 20-20kHz)
Per Channel into 4ohms .... 50W x 2 (0.08% THD)
Per Channel into 2ohms .... 100W x2 (0.3% THD)
Bridged 1 Channel into 4ohms ....200W x 1 (0.3% THD)

 

You're going to have to experiment with the gain until you are happy with the relative level compared to the rest of your (front) system.
As for the crossover setting, I recommend starting with it set to 120 Hz lowpass first, then trimming it downward if you find that the bass is too sloppy or boomy for you. The reason to start off with the frequency set that high is because the new woofer should compensate for the lack of bass capability from the rest of your system. If you set the freq to 80 Hz or so, you may find that there isn't enough bass and that there is a hole in the bass (missing bass).

 

thanks alot for the input i'll try it out

 

So i just got my sub in the mail today and installed it hooked it up to the amp and for some reason the sub cuts out when I turn up the volume is it the sub or the amp thats the problem? as of right now its bridged.
could it be the head unit? right now Im stock
any feedback would be great
thanks

 

alright so i found another amp lying around and this one seems to power it a little better before it cuts out so the question is no what is the best amplifier out there for this Sub
Bang for Buck thanks

 

When you say "cuts out" what exactly do you mean? How long does the audio cut out (goes silent?) before it comes back on? Do you hear any clicks when it cuts out or comes back on? Does it come back on by itself, or do you have to turn down the volume or turn off/on the system again?

Since you find the same problem with two different amps, it is probably not the amp or the speaker, but either the head unit, or the way it is driving the amps. What is the head unit, and how is it connected to the amp?

 

as of right now It is connected to the head unit with a RCA converter connnected to the signal from the 2 rear component speakers
when i turn up the volume the subwoofer goes out I either hafta turn down the volume or turn down the bass adjust on the stock headunit for the subwoofer to start to working again theres a slight distortion when it gets up and running again and Like the bass even isn't that loud before it shuts down so I dont know whats its beef

 

Just to confirm, the RCA converter is some sort of LOC, not just a wire adapter, right?

Couple of things to check, but you will need an AC/DC voltmeter. They are not too expensive--Radio Shack has them.

1) Monitor the battery 12v line into the amp as the volume goes up and the sound cuts out. Is it holding pretty steady around 12v, or does it drop a few volts or more? If so, check the 12v lead, connections, fuses, etc. If it's fine, then:

2) Amps should have DC blocking capacitors, and if you turn on the subsonic filter in the V12, then there should be no DC issues with the amp input. Do you have it switched in? Try that.

3) If that's looking OK, then have a look at the audio signal coming out of the LOC -- feeding the amp. For this test the voltmeter needs to be switched to the AC mode, and hopefully it has enough sensitivity to read a few hunderd millivolts. It will be easiest of you use a test disc with some steady bass frequency tone on it, like 50 Hz. As the volume is increased, the voltmeter should show that. As the amp cuts out, what's happening to the signal? Still steady and increasing with volume, or also cutting out or fluctuating?

 

so i did another test... this amp was previously powering my 12inch W0 from my old car so I threw that in there and wired it up and it was pounding like it use to... im starting to think that its possibly the amp because the IB4 runs on 8 ohms and 100 watts but bridge Im getting 4 ohms at 200 is this the problem?

 

What is the load presented by the W0 woofer? Seems to me the IB4 would be easier to drive, being an 8 ohm unit.

 

125 watts either at 8 ohms or 4 ohms not sure which one i have. the sub is pretty ancient

 

The Issue has been resolved thanks alot for your help drex
but it was a simple wiring issue because when i hooked up the subwoofer I wired them to the stock connectors this which was attached to the stock clip and therefore the stock amplifier there must have been a signal running into it shutting it off somewhere so.. now the amp is just hooked directly to the subwoofer terminals and The bass is amazing. JLIB4 thumbs up...I think it sounds way better than if I had a box in the trunk

 

Congratulations on fixing the problem. Thump on!