subs cutting out..

[inline 6]

In my jeep if I turn the bass up a nice bit and little by little start to turn the volume up it will get to a point to where the bass completely drops out. If I turn the volume down one notch it will come back in and then in reverse if I go back up one notch it will drop back out and maybe an occasional note will hit. I didnt think that I had a powerful enough setup to challenge the electrical system on my jeep. Here is the setup, give me any info that you can....

Stock alternator and regular battery,
running 4g wire to a distribution block that is split for 2 amps.
1st amp is a 400w rms 4ch class A/B for mids and highs. 2nd is a class D 750w rms. I have an upgraded alternator for the jeep but was waiting to install it until I get other thnings that really require it. Would just putting this in fix me up or am I needing other stuff here? I was watching the voltage while driving on my torque obdII app and it runs at 14.1 all day. When heavy bass is present it will drop down into the low 13v range. I didnt see if it ever went as low as the 12v range but I suspect that it did.

[BP]

Does the sub amp have a protection mode?

[jluv]

4 gauge isn't enough to properly run over 1000 watts, assuming your run is longer than 12 feet. You could be starving your amp of power, or worse - you could end up melting the wire. Most likely it's low voltage protection on the amp that's causing the temporary loss of power.

Might even be thermal protection, but that's less likely unless you are running too low of an impedance or don't have good ventilation around the amp. It would probably shut off for longer periods, though, until it cools off, so I doubt that's your issue.

Are your gains set properly? It's not a volume knob. You probably know that, but a lot of people don't, so just asking...

Where are you getting your voltage reading? Don't consider it accurate unless you're using a meter, and sometimes the bass notes are so quick you will not see how low it really goes.

[BP]

Where are you getting your voltage reading? Don't consider it accurate unless you're using a meter, and sometimes the bass notes are so quick you will not see how low it really goes.

This is very important, your OBD2 app is reading PCM voltage. I'd put an actual meter on the leads into the amp. As Jared noted 4 gauge is pretty small for that kind of power and the hotter those wires get the lower amount of current they can flow.

[Z06killinsbf]

What brand are the amps?

[Baron Von Crowder]

factory head unit?

[EW]

factory head unit?

X2

[inline 6]

Ok, I have the gains for the sub set very conservatively if anything they are set low. I adjust the subwoofer output at the head unit a little bit from time to time but the amp gains are never adjusted and I do not have a remote knob. I am 100% sure it is not thermal protection cutting it off as I said it will come right back with one down click of the volume. It is an aftermarket hu, Alpine HD149BT to be exact... specs here...

http://www.alpine-usa.com/product/view/cde-hd149bt

Amp is this one from JL audio....

http://www.jlaudio.com/hd750-1-car-a...plifiers-98220

It is pushing a pair of these that are also from JL and it is wired correctly for sure.

http://www.jlaudio.com/10w6v3-d4-car...-drivers-92140

As far as the voltage, I cant watch it constantly as I am driving but when the bass is steadily going I can watch the voltage of the vehicle go down. I cant measure individual low spikes just an overall average. I also have my OBDII adapter set to read actual voltage and not the PCM voltage. ALSO, the 4g run of wire is about 6' It comes straight off of the battery which is on the passenger fire wall and drops strait down into the cab and under the door sill plate to right under the passenger seat. Its a short run it may not even be 6'

[jluv]

I run two of that exact same amp, and I think they do not like to be starved for power. Mine would do the exact same thing when I really jammed on them in my Explorer. I had a 250 amp alternator and a Kinetik HC2400, big 3, and 1/0 power and ground to the distro block and 4 gauge to all 4 amps. The voltage would drop dramatically on big bass hits and it would cut off, but only when I was really pounding on it. I don't think it was clipping but it could have been. I think they were just not getting enough juice. May have something to do with them being regulated.

I have since put those amps in my F250 instead, with two big Kinetik batteries, a 370 amp alternator, two runs of 1/0 to the distro block, etc. The install isn't finished yet, but I expect it to never have that issue again. We'll see.

Most stock electrical systems are very weak. And a lot of amps on the market are rated at 14.4v, and when they dont get that much voltage, they drop their power output dramatically. These JL amps are going to put out their power regardless, even at the cost of straining your vehicle's electrical system. At least, that's my theory. I'm no engineer.

How long have you had your amp? JL recalled them a while back. I had to send both of mine in and have them fixed (for free). I can't say for sure if that fixed this issue or not. I have hooked one up and banged on it, and it didn't shut off. I only ran around with that setup for a couple of days.

I will post an update once I get this new install done. We'll know for sure if it's a voltage issue, because I'll have more than enough.

[inline 6]

I checked it over when I got it and it was made after the date that was needed to send it in. I forgot to say that I didn't replace the ground wire to chassis with anything larger. Maybe I should look into that.

[EW]

What is the l.e.d. on the amp doing when the bass cuts off? It will blink and change colors to tell you what is going on.
If the ground from battery to chassis and battery to frame has not been upgraded, it should be.

[inline 6]

Ok, I was just able to check this yesterday. The led when it drops out is flashing red/green. The manual states that either the amp has an issue or the charging system is weak. Since we have all seen issue with this in my setup I am going to upgrade the alternator with the one that I already have, go get a diehard platinum battery that I have been wanting anyway, and upgrade all charging and amp supply cables to 0 gauge. I have also noticed this morning that one of my headlights did not want to come on and was acting funny. They are some aftermarket complete replacement DOT approved LED headlights. I am pretty sure that they dont like to run without the right voltage.