# Help - bass cut out while driving ???



## duckymcse (Mar 15, 2009)

Help me, I can't figure this out.
It only happen when I drive and turn the volume up loud with a song that have hard hitting bass, my subwoofer loose the sound temporary and came back within a second over and over again. This is only happen when I am driving.
If I park(not driving) with engine on, I don't experience that problem at all.
What is the most likely the cause of it?


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## hcbassplay (Jun 19, 2005)

Sounds like your sub amp is going momentarily into protection, what are you running?


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## dolbytone (Jun 30, 2010)

Have you investigated all of the obvious possibilities like power/ground connections or a damaged wire that could be grounding out?


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## kyheng (Jan 31, 2007)

Get your self a multimeter and start measuring your voltage at battery, amp's power supply and distribution block... Looks like either is you got high resistance on connection or your altenator not producing enough power(unlikely?)....


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## waylouderthanyou (Dec 22, 2009)

it can be the voltage is to low at the amp and it is shutting off and coming back on to protect itself _or _the coil in your subwoofers are bad. if one coils is bad and you hit a certain hertz the amp will read the bad ohm load and reboot itself. had this same problem with my zapco 9.0 pusging a dd 9515. one week later, both sub coils blew.


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## waylouderthanyou (Dec 22, 2009)

btw, what kind of amp and sub are you running?


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## duckymcse (Mar 15, 2009)

JL 12W7 sub with JL HD 750/1 amp.



hcbassplay said:


> Sounds like your sub amp is going momentarily into protection, what are you running?


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## duckymcse (Mar 15, 2009)

If I park with engine on (not driving), everything work fine. I'm sure my power and grounding is good. 



dolbytone said:


> Have you investigated all of the obvious possibilities like power/ground connections or a damaged wire that could be grounding out?


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## duckymcse (Mar 15, 2009)

I went to Walmart and purchase one of these: Innova Equus 3721 Battery and Charging System Monitor
Great little device for $15 to monitor both battery and alternator. I highly recommend getting one if you can find one.
The first thing I test is the battery and my battery failed the test. It is holding charge at 12.1V which is not good.
I notice during driving, my charging system (Alternator) voltage fluctuating between 12.3V - 14.4V. When the voltage drop under 13V, my subwoofer lost the bass note. When the voltage stay over 14V, my subwoofer hit hard and loud without problem.
Look like both my battery and Alternator is not good.
But I still don't understand why when I park with engine on (not driving), everything work fine.



kyheng said:


> Get your self a multimeter and start measuring your voltage at battery, amp's power supply and distribution block... Looks like either is you got high resistance on connection or your altenator not producing enough power(unlikely?)....


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## duckymcse (Mar 15, 2009)

Yeah, you are right. Voltage is too low.
How did you manage to fix the problem?



waylouderthanyou said:


> it can be the voltage is to low at the amp and it is shutting off and coming back on to protect itself _or _the coil in your subwoofers are bad. if one coils is bad and you hit a certain hertz the amp will read the bad ohm load and reboot itself. had this same problem with my zapco 9.0 pusging a dd 9515. one week later, both sub coils blew.


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## kyheng (Jan 31, 2007)

If you are getting low voltage, that's means you have high resistance on your ground or power.... That's why a multimeter are the best tool to know everything.

JL amps can go as low as 8V before it shut it self down... Tested this on my JL A6450....


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## Oliver (Jun 25, 2007)

http://www.diymobileaudio.com/forum...ced/93523-amp-randomly-goes-into-protect.html

Same thing I have seen repeatedly on forums, *then amp gets r-e-p-l-a-c-e-d
*


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## dolbytone (Jun 30, 2010)

duckymcse said:


> If I park with engine on (not driving), everything work fine. I'm sure my power and grounding is good.


So that's a no. If you are driving things are vibrating which would make a poor connection or skinned wire more likely to make itself known. Don't just assume your connections are good because it doesn't do anything at a stand still.

You need to actually check this stuff as part of the process of troubleshooting. Throwing darts at the problem and picking what the dart lands on is not a methodical way of finding a problem. You should start from Step 1 and move through the system in logical order. This way we can eliminate possible causes and move forward with confidence instead of going around in circles when this or that doesn't magically resolve the issue.


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## fish (Jun 30, 2007)

Just saw this thread earlier...

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/93545-jl-audio-amp-recall.html


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## duckymcse (Mar 15, 2009)

Thanks for this headup. Mine is part of the recall 
I probably wouldn't have bass for 2 week once I send it back to JL for the recall. Felt like the world is crumbling down without bass in the car, LOL.




fish said:


> Just saw this thread earlier...
> 
> http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/93545-jl-audio-amp-recall.html


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## duckymcse (Mar 15, 2009)

I don't think my amp shutdown at all. I just lost the hard hitting bass at loud volume for like less than 1/2 second. I think if the amp shutdown, it take longer more than that to come back up.
Today, I notice that while driving if my RPM is above 2500, my subwoofer hit hard without any problem. To keep above 2500, I have to drive close to 80MPH consistantly.
I suspect my Alternator is not produce enough juice under 2500 rpm or my battery is not holding enough charge to satisfy the instant hard bass note.
I got 3 choice to experiment.
1. Replace the battery with a AGM deep cycle battery
2. Upgrade my stock power/ground wiring to the BIG 3
3. Replace the Alternator with a higher AMP

I'm going to give #1 and 2 and try and see how it's go.
Replacing the Alternator is the last thing on my mine  



kyheng said:


> If you are getting low voltage, that's means you have high resistance on your ground or power.... That's why a multimeter are the best tool to know everything.
> 
> JL amps can go as low as 8V before it shut it self down... Tested this on my JL A6450....


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## kyheng (Jan 31, 2007)

Why you never consider a multimeter first? Rather than spending money for no reason.....


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## duckymcse (Mar 15, 2009)

I don't see how I can test with the multimeter while driving.
Remember, everything work fine if I don't drive.



kyheng said:


> Why you never consider a multimeter first? Rather than spending money for no reason.....


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## dolbytone (Jun 30, 2010)

Just because the issue occurs when you are driving doesn't mean you need to be driving to test for good connections. Taking down some measurements with a multimeter is good advice. Once you have confirmed everything is good, it then makes sense to spend a little money, but not before checking a few other things...

Does it run fine without turning the vehicle on? I can play my stereo full blast with no issues and I'm using a larger amplifier than you are. You should be able to do the same, but if not, it would then make sense to look at getting a new battery.

Point is, figure out what it is first, then fix it. Don't just go replacing things with no plausible cause.


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## duckymcse (Mar 15, 2009)

My battery run out of charge in less than 10 minutes if I don't turn on the engine. That was 3 months ago. I wouldn't dare to run my audio system without turning the engine on since than. It's ain't fun when your car don't start in the middle of nowhere 
I don't have a voltmeter to measure. I'll get one and learn from it. 



dolbytone said:


> Just because the issue occurs when you are driving doesn't mean you need to be driving to test for good connections. Taking down some measurements with a multimeter is good advice. Once you have confirmed everything is good, it then makes sense to spend a little money, but not before checking a few other things...
> 
> Does it run fine without turning the vehicle on? I can play my stereo full blast with no issues and I'm using a larger amplifier than you are. You should be able to do the same, but if not, it would then make sense to look at getting a new battery.
> 
> Point is, figure out what it is first, then fix it. Don't just go replacing things with no plausible cause.


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## kyheng (Jan 31, 2007)

^Well said.... Using a cheap multimeter is know what actually happens. With car stopped and if you are getting voltage of <10V, you should know what needs to be done, like cleaning the connections, checking the ground...
You may spend $$$ to upgrade everything, but without knowing the actual cause, you are sweeping dirt to below your carpet. Samething will still happens later on. I learn this in the hard way by wasted $$$ to change battery but later found out dirty connections that causes all the problems....


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## Oliver (Jun 25, 2007)

duckymcse said:


> My battery run out of charge in less than 10 minutes if I don't turn on the engine. .


Irst step *replace battery*


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## tanakasan (Sep 8, 2007)

duckymcse said:


> My battery run out of charge in less than 10 minutes if I don't turn on the engine. That was 3 months ago. I wouldn't dare to run my audio system without turning the engine on since than. It's ain't fun when your car don't start in the middle of nowhere
> I don't have a voltmeter to measure. I'll get one and learn from it.


10 minutes!?! Battery replacement needed!

Robert


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## Oliver (Jun 25, 2007)

also , a few guys will tell you to check your grounds


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## IamMightyJo (May 27, 2021)

Why does my subs cut off when I hit a bump? Then only turns back on if I turn my truck off then back on?


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