subwoofer isn't hitting with the music, instead it just kind of pulses weird

[atown 10+ year member]

I just installed a sub/amp in a 99 pontiac grandam, but it won't hit to the music, as I adjust the gain and freq on the amp it eventually just starts pulsing or vibrating.

At first I thought it might be the remote wire, so we ran a new one, but it's having the same problem.

Amp: MTX Blue Thunder 300x2

Sub: JL w0 8ohm

I also tried hooking up a JL w3v2 4ohm to it, and (unless I didn't turn the amp up enough to see it) it didn't vibrate at all.

Click to read more...

 

[old_dude 10+ year member]

Not that it's important, but may I inquire as to the deck you are running in your dash? I'll assume not the factory one. Your problem sounds odd. I'm not an expert, and I don't doubt someone with a bit more knowledge will know the answer. But my opinion: I would try a different amp and see if it solves the problem. If so, you know your MTX is at fault. If not, I would next wonder if you are running RCA's or Line Level outputs from your deck to the MTX. Is the deck new? In general, if I were to experience your problem and I already checked another sub, I would check another amp, then see if my deck's outputs were fried or something.

I'm curious about your problem. Please keep me updated on what you find out.

 

[loopkiller 10+ year member]

Sounds like your RCA cables are grounded out at some point. You can test the amp with an iPod and a 3.5mm mini jack to RCA cable like the one pictured below. You should be able to get one at Radio Shack for a few bucks.

If your subs work fine with the iPod, then you have a problem with your RCA cables or your head unit. If you are using a line out converter (LOC), it may be to blame as well.

 

[atown 10+ year member]

I took the sub and amp straight from my other car, so I know it's not either of those. The original amp that I wanted to put in this grand am car was a JL 500/1 but once I had it installed it wouldn't stay powered on for more than 10-20 seconds and even then the sub was hitting very lightly, so that's why I decided to change to the mtx amp, just so I could get it going for now. I don't know why it (the jl 500/1) is hitting lightly, though I'm assuming it can't get enough power from that car. (hooked up to my 99 honda passport though it does seem to get plenty of power)

The deck is a JVC KD-JDw10, it is a new deck I got it about 6 months ago and that's when I installed it. I'm running RCA's from the subwoofer output on the deck to the sub.

with the RCA thing you're talking about, do you mean I should go directly into the amp with one of the Y-RCA cords? I have a few of those cords laying around so that won't be a problem to try.

 

[loopkiller 10+ year member]

Yes plug the 3.5mm mini jack into the iPod and the RCA end directly to the sub amp. You will still need to turn on the head unit so the amp turns on, or jump the POS+ connection to the REM input on the amp. That will rule out the amp, subs, and wiring to the sub. If you have no issues, then you will need to check the other end of the RCAs. You would need the opposite gender on the RCA end, or a small female to female adapter/cable. If it still plays fine, the issue is in your head unit.

 

[faiz23 10+ year member]

I took the sub and amp straight from my other car, so I know it's not either of those. The original amp that I wanted to put in this grand am car was a JL 500/1 but once I had it installed it wouldn't stay powered on for more than 10-20 seconds and even then the sub was hitting very lightly, so that's why I decided to change to the mtx amp, just so I could get it going for now. I don't know why it (the jl 500/1) is hitting lightly, though I'm assuming it can't get enough power from that car. (hooked up to my 99 honda passport though it does seem to get plenty of power)
The deck is a JVC KD-JDw10, it is a new deck I got it about 6 months ago and that's when I installed it. I'm running RCA's from the subwoofer output on the deck to the sub.

with the RCA thing you're talking about, do you mean I should go directly into the amp with one of the Y-RCA cords? I have a few of those cords laying around so that won't be a problem to try.

check your ground, the jl amp should not have any issue and is more reliable than the mtx, something in the wiring is causing issue. throw the jl amp and try to make it work, unless it is defective. i think something is not wired correctly or ground are not good.

check resistance on the ground and the battery neg

 

[grimreper912003 5,000+ posts]

check your ground, the jl amp should not have any issue and is more reliable than the mtx, something in the wiring is causing issue. throw the jl amp and try to make it work, unless it is defective. i think something is not wired correctly or ground are not good.
check resistance on the ground and the battery neg

What? //content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif

Seriously?? I have ran a 1000/1 and a TA7801, both amps were reliable and never went into protect. Why would you say the JL is more reliable? Because its JL?

 

[natisfynest 10+ year member]

What? //content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif
Seriously?? I have ran a 1000/1 and a TA7801, both amps were reliable and never went into protect. Why would you say the JL is more reliable? Because its JL?

duh hes a fan boy

 

[ahillworks 10+ year member]

I had a customer with the same issue. Ended up being the head unit. Make sure you do not have a ground loop some where. Check wiring for head unit and for the amp. Make sure your grounds are good grounds. May also want to get a Ground Loop Isolator if anything else. They look like this.

Good luck.

 

[faiz23 10+ year member]

What? //content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif
Seriously?? I have ran a 1000/1 and a TA7801, both amps were reliable and never went into protect. Why would you say the JL is more reliable? Because its JL?

umm no, i am not a jl fan boy, i am a fan boy for quality products.

jl is of higher quality compared to some of the other brands. Yes they are **** expensive and gone mainstream, but if you can get a jl amp for a good price than you are set. You get a regulated power supply which sets it apart from the competition, have all wattage available at all time is very nice to have. I love the tuning options on there amps and having a bandpass filter on the highs amp and being able to adjust Q, center freq, subsonic, and other features as well. I am not saying jl is the **** but they make some quality products and demand a premium for it. i have all jl amps in my car and my girls car call me a fanboy, but then you would have to call me a focal fan boy as well as my girls car has all focal highs. What about stinger i use their wiring as well am i a stinger boy now lol.

i think a fanboy is one that has tunnel vision and only see's one brand and makes a system solely consisting of that one brand.

I know you can buy other brands just as good if not better, but my point was a jl 500/1 should be able to bump a sub that the op was using. it did not sound right that the amp was not playing anything. I think op needs to look at his wiring or have some equipment bench tested.

 

[GMCJimmyslt2000 10+ year member]

Sounds like u have a poor ground.

Where it located?

Did u scrap away paint and make sure u have good contact?

 

[DidUHearThat? 10+ year member]

Sounds like loose power or ground connection. Check at the fuse locations, look for burn marks or corrosion. Clean the contacts and tighten them down.

As suggested above, plug an ipod or cd player directly into the amplifer RCA inputs to see if the problem is your head unit/RCA lines.

 

[denali804 10+ year member]

Is the subwoofer volume turned up on your jvc deck?????? Also what subwoofer settings do you have on that deck??????

 

[KyleBechtold 5,000+ posts]

i put my bet on ground.. the jl probably went into protect from low voltage.. and with the loose ground it vibrates and the changing in power makes the subs pulsate..

 

[faiz23 10+ year member]

i put my bet on ground.. the jl probably went into protect from low voltage.. and with the loose ground it vibrates and the changing in power makes the subs pulsate..

that is what i thought that a bad ground threw the jl into protect, where the mtx was able to play with a bad ground since it does not have the regulated power supply and is not as picky as the jl.

check ground, check resistance,