Sub going out at higher volume

[blazed]

So I've had these 2 Memphis 12' subs, 800watt good AMP and they work working great. Right until I got my car battery replaced. I believe the battery they installed was a knock-off chinese crappy battery, so there isn't much power. As soon as I got the battery, I noticed a slightly slower car, as in it would take much longer to go from lets say 0-30 or anything, just a lot slower acceleration. But mainly, it affected my subs, at least that's what I think. My volume is 0-62. Whenever I go around 40-50, depending on the song, the song continues, but the subs cut out. I have to turn the volume down until the subs start working. I have even put all of the sub settings to the lowest, like all of the MHZ and HZ settings and stuff from the car audio faceplate. So I am thinking of getting a capacitor, but its around 125$ installed, so I don't want to get the wrong thing and still have the problem. My question is will this capacitor really be worth it? Will it get my audio system back to the way it was? Like 60 volume, FULL bass, and still working, and bumpin'? Or should I get my car battery replaced? What exactly is the problem and how should I fix it? Thank you!

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[audioholic 5,000+ posts]

The problem sounds like low voltage, as you seem to already suspect. Exactly how or why is hard to say without more info.

What I dont understand is, you say these problems all started when the batt was replaced with a cheap chinese version, yet your idea to fix the problem has nothing to do with the battery.

 

[blazed]

im blazed right now. but when i checked prices of battery, they were about 20$ more. and im just not sure if that was the problem 100%, im just guessing it is

and what other info would be helpful? ill try to get it

 

[dadydolas 10+ year member]

My sub does the same thing. I think it is either your new battery, as that is when the problem began. or you may have had your amp set improperly and now something has went bad inside and its on its way out.

 

[audioholic 5,000+ posts]

Well if the problem occurred once the batt was changed, that's already a pretty strong case for the batt being the problem. If its literally hurting the engine's performance, Id have it looked at anyway. Id suggest returning to where you purchased the batt and explain your problems/concerns to them. Im honestly not sure at this point how a poor battery would consume so much engine power, but I believe you when you say that is the case. So assuming that is true, there must be a major voltage problem, and should be easy for a batt shop to diagnose.

a cap, especially in this situation, is merely a bandaid to cover over the real problem. A new batt may be a few dollars more, but its the 'right' fix, its still cheaper than buying a cap and realizing it didn't help much, if at all. Caps dont create power, and if the batt is starving the car for voltage, the cap will probably make the problem worse, not help it. After all, any power the cap would receive would still come thru the battery (from the alt).

 

[audioholic 5,000+ posts]

My sub does the same thing. I think it is either your new battery, as that is when the problem began. or you may have had your amp set improperly and now something has went bad inside and its on its way out.

Sub cutting out at high volumes is a very common problem, virtually always due to low voltage, and almost never truly fixed by adding a capacitor. A good way to test this would be to adjust your bass down (either at the h/u or the amp's gain controls) and then see if the system's volume can be turned up to a higher level on the deck before cutting out.

 

[dadydolas 10+ year member]

Sub cutting out at high volumes is a very common problem, virtually always due to low voltage, and almost never truly fixed by adding a capacitor. A good way to test this would be to adjust your bass down (either at the h/u or the amp's gain controls) and then see if the system's volume can be turned up to a higher level on the deck before cutting out.

so your saying it is more likely to be the voltage rather than the amp. or just commenting

 

[audioholic 5,000+ posts]

so your saying it is more likely to be the voltage rather than the amp. or just commenting

Amplifiers have protection circuitry in them that puts them into 'protection mode' when the voltage gets too low (or high). The power supply type in the amplifier will affect its ability to handle voltage deviations, but even loosely regulated power supplies tend to have this precaution.

To answer your question, Im suggesting low voltage is causing the amplifier to shut off, as its suppose to do. This should not be looked at as a fault of the amplifier, but as a problem with the charging system.

 

[dadydolas 10+ year member]

good to know thanks

 

[blazed]

A good way to test this would be to adjust your bass down (either at the h/u or the amp's gain controls) and then see if the system's volume can be turned up to a higher level on the deck before cutting out.

yea i did that so much. i have it on the lowest settings right now, and I get 47 sometimes.. just depends on the song really. it probably is the battery then, i will have that checked out, thank you very much for all the info

also, i just want to make sure, a weak battery COULD cause these problems right? ie, the engine slowing down because less juice and subs cutting out at higher volumes. i just really want to know if its a possibility its the battery.. because the person who replaced it was my dad who is a mechanic haha.

im guessing he just thought the old battery was old and replaced it with his own, and he does tend to "save" alot, so i'm guessing it was a really cheap quality one, but even if it was, is this all possible? thats what im tryin to understand, thanks again for all the info.

 

[audioholic 5,000+ posts]

It makes alot of sense in regards to the stereo. A poor performing battery will, of course, limit power supplied to the stereo, and create a problem much like you describe. As for hurting engine power and over all acceleration, that's a new one on me. In theory, once the car is started, it should run with no battery at all, as the alternator is what actually creates the electrical energy for the car. But this created energy still passes through the batt, and that could diminish voltage to the car's computer, which I suppose might affect how it controls the engine, and thus hurt performance. But like I said, I dont think Ive ever heard of replacing the battery really affecting acceleration of the vehicle. Talk to your dad and see what he thinks. Mysterious problems like this are much easier to troubleshoot in person than through a computer.

Glad I could be of help.