i was driving the other day, with my system pretty loud as i allways do, and all sound cuts out, since i have 2 amps, one for the sub and 1 for the speakers, i assumed it was the fuse at the battury terminal. i have blown this once before about 6 months ago and i replaced the fuse and everything was fine, so i replaced the fuse again, but unless the volume is down very low, my sub will start to beat but then cut out from the protection circuits within the amp. when i have the engine off, the sub will beat fine, but when the engine is running, the sub cuts out. so i put my mates sub in my car to see how that would work. it works fine. so my guess was my sub is busted?. can any one help?

Check the voltage going to the amp too. I would suspect that the amp may be damaged, and if the car is running, the input voltage will be higher than standard 12v (probably around 14v) and protection circuits may be triggering unnecessarily.

All in all I'd say the amp is stuffed though... maybe try another amp with your sub just to check there isn't a short somewhere else (I have heard of coils in subs shorting out and pulling impedance too low). Also - can you confirm if the amp is actually dying when this happens? It could even be the head unit remote trigger that turns on the amp is not working correctly.

Check the voltage going to the amp too. I would suspect that the amp may be damaged, and if the car is running, the input voltage will be higher than standard 12v (probably around 14v) and protection circuits may be triggering unnecessarily.

All in all I'd say the amp is stuffed though... maybe try another amp with your sub just to check there isn't a short somewhere else (I have heard of coils in subs shorting out and pulling impedance too low). Also - can you confirm if the amp is actually dying when this happens? It could even be the head unit remote trigger that turns on the amp is not working correctly.
He has put his mates sub in and it works, so it has to be the sub. Strange that it works with the engine off but not with it on :think:. The only difference is that the amp will getting a little bit more voltage, so the sub may have a short.

check sub wiring at the sub and at the amp, its prob shorting out somewhere ur amp is going into protection as it cant handle the low impedance.

Check the resistance across the terminals.

i checked the impedance across the subs terminals and i couldnt get a reading, it was giving off wild readings, so i checked my mates sub to make sure the multi meter was workin and it was reading 4.2 ohms, so yeah, i just got a quote, to do a recoil, was $165 so i think mabey i should just buy a new sub, i just dont know what caused my sub to die on me, i was running the 300 WRMS sub on 200WRMS amp, and i never herd any distortion or clipping, if the crossover frequency was set too low, would that damage a sub?

i checked the impedance across the subs terminals and i couldnt get a reading, it was giving off wild readings, so i checked my mates sub to make sure the multi meter was workin and it was reading 4.2 ohms, so yeah, i just got a quote, to do a recoil, was $165 so i think mabey i should just buy a new sub, i just dont know what caused my sub to die on me, i was running the 300 WRMS sub on 200WRMS amp, and i never herd any distortion or clipping, if the crossover frequency was set too low, would that damage a sub?
if its ported yes it can, as you shouldnt play below the tuned freq ideally you should have a subsonic filter for ported subs.

I'd say the more likely scenario is you had the gains on your amp too high and you were clipping the sub; caused ur VC to fry.

What VC config is the sub? 4 ohm? or dual 4/dual 2?

if its ported yes it can, as you shouldnt play below the tuned freq ideally you should have a subsonic filter for ported subs.

I'd say the more likely scenario is you had the gains on your amp too high and you were clipping the sub; caused ur VC to fry.

What VC config is the sub? 4 ohm? or dual 4/dual 2?


I would like to know what the VC config has to do with it? I'm asking because mi rockford sub stopped working all together one day halfway through a song. And it is 4-ohm DVC

the sub was sealed, and its a single voice coil, at 4 ohms, i can see the coil through vents and it looks/smells burnt, how can i prevent it from happening again, all my wiring is more than adequate, running 200WRMS on a 600W max sub, which is about 300WRMS should i install a cap?, the original amp which i bought with the sub, which they said would be fine, was less power, i didnt want to risk clipping and to make it sound better i upgraded the amp. are there any crossovers out there that i can change the freq by remote, just like the gain on my amp?
is it possible to pull apart the sub to get the coil and do a rewind on it myself?

What's the brand and model of the sub?
Just because it is 600wmax doesn't mean it's 300wrms.
What brand and model amp are you running?
What are the specs of the amp?
Are you running the amp in bridged mode at all?
Have you properly level set the system/subs?

What's the brand and model of the sub?
Just because it is 600wmax doesn't mean it's 300wrms.
What brand and model amp are you running?
What are the specs of the amp?
Are you running the amp in bridged mode at all?
Have you properly level set the system/subs?

it was a clarion SW12 or somthing and a jay car responce amp 2X80WRMS bridged giving 200WRMS AA0420 model MOSFET what do you mean by level set?

it was a clarion SW12 or somthing and a jay car responce amp 2X80WRMS bridged giving 200WRMS AA0420 model MOSFET what do you mean by level set?
By level setting a system (I might have the wrong terminology?) you turn the gains down on your amp, turn your headunit on max volume (and max bass/subout if you use this feature), then turn the gain slowly up on your amp until you hear distortion and/or clipping, and then turn the gain down slightly to just before this point.

This way you can never under/overpower your sub/s. Even though you may not have heard clipping from inside your car with music playing, doesn't mean it wasn't, because often the bass can drown out the clipping sound unless you have your ears right next to the sub.

oh ok i dont think i set the level then, the sensitiyity level was 3/4 and the bass boost was more than half, but i dont think there was any distortion. i have had the sub for a year

the sub was sealed, and its a single voice coil, at 4 ohms, i can see the coil through vents and it looks/smells burnt, how can i prevent it from happening again, all my wiring is more than adequate, running 200WRMS on a 600W max sub, which is about 300WRMS should i install a cap?, the original amp which i bought with the sub, which they said would be fine, was less power, i didnt want to risk clipping and to make it sound better i upgraded the amp. are there any crossovers out there that i can change the freq by remote, just like the gain on my amp?
is it possible to pull apart the sub to get the coil and do a rewind on it myself?
A cap will do absolutely nothing to stop this happening again.
As it is sealed you wont require a subsonic filter.
The sub should be able to handle any frequencies you throw at it.
I would set the gains a bit more conservatively on the amp, dont crank it as much, or better yet, spend more $ on a better sub.

From what you say I think you were feeding a bit too much power in. If your headunit has high voltage RCA outs eg => 4volts and you were using a loud source with lots of bass then it may have been enough to do damage. Bass boost is evil and shouldnt be used... :) (but thats just me being picky)


I would like to know what the VC config has to do with it? I'm asking because mi rockford sub stopped working all together one day halfway through a song. And it is 4-ohm DVC
Voice coil config can change what load your amp sees. If you have a 4 ohm SVC you are fine as it will always be a 4 ohm load, but if you have a 4 ohm DVC you can wire it in series = 8 ohm load, or you can wire it in parallel = 2 ohm load.

Say you wire it at 2 ohms your amp will now be seeing a 2 ohm load. In comparison to a 4 ohm load the amp will now put out twice as much power into your sub as it is driving a lower impedance. (providing your amp can handle that load; if it cant handle that load it will most likely go into protection)

But if it is setup right and you are aware of what load the amps are seeing, what power your amp puts out then, what your speakers can handle and make sure the gains have been matched correctly you'll be fine. Most importantly listen to clipping and dont ask more than your gear can provide.

i keep hearing about clip limiters, are they any good at preventing clipping or are they expensive.

never heard of them, but if you: set the gains sensibly; get over the whole louder is better thing, and resist the urge to crank your tunes beyond what the gear is capable of you wont have a problem with clipping or damaged gear.

If you want to get loud; thats all good... Buy gear that can put out/handle that kind of power.

If in doubt set your gains lower, mine are really low, I drive around with my headunit on MAX sometimes (most headunits will distort above 75% though so I wouldnt recommend this)

When u set your gains turn them down to min on the amp, play a few cd's or test tones set your headunit to the loudest it will go to before distorting, slowly bring the gains up until the speakers just start to clip, back off a few degrees where you know it will be safe.

Now it doesnt matter if your drunk friends jump in the car and crank the tunes while your driving as you know that the gear cant distort.

This has more benefits than this. it means that when you are listening to music where your headunit will normally be at 1/5 volume and really pumping, you can now use the entire volume range, so you have more volume 'steps'; it is now easier to find the perfect volume. Most headunits have better dynamics when their output is higher and better noise rejection as well.

:)

Peace

Tim

oh ok i dont think i set the level then, the sensitiyity level was 3/4 and the bass boost was more than half, but i dont think there was any distortion. i have had the sub for a year
hmmm as Tim said i think you have your gains set too high, do you know what your pre-out voltage is on your headunit? If it's around 4/5v i'd say it could well be your gains, esp. seen as you had bass boost on which i've personally found to cause clipping more than improper gain settings, but not sure if it was just my setup or not.

i keep hearing about clip limiters, are they any good at preventing clipping
or are they expensive.
Never heard of them, but If their sole purpose is to stop clipping, they sound like a waste of money because a properly tuned system won't have clipping issues.

Preventing clipping really isn't all that hard... just don't turn the volume up so far lol

Clipping can actually happen at any time, and in some cases isn't even noticeable. It occurs when the amplified levels go beyond the rail voltage of the amp (which in the case of a car is obviously typically 12v). Usually it means that the peaks and troughs of the waveform get "clipped" or flattened out while the rest of the waveform stays the same (which is why it may not always be noticeable when this is occurring). When it hits the point where the waveform is clipping, the output going into the sub is actually a DC square wave, rather than a typical AC waveform. This causes rapid overheating of the coil, eventually causing it to fail.

The theory behind the way a standard speaker works is by moving coil inside a permanent magnetic field. The movement is based on an AC waveform forcing the rapid back-forward motion of the coil (and thus the cone) within the magnetic field. If you just run a DC waveform in, the coil will be held still at the farthest end of the coil travel, and draw an excess of current causing overheating. It's a very similar theory to the way transformers operate - they can only use AC, as the rapidly reversing field is what induces a voltage in the secondary coil. If you put a DC voltage through, it will just overheat the coil and cause it to fail very quickly (as it is effectively a short circuit).

ok enough theory... as others have suggested - fix up the level, and don't overdrive the sub. However, in some cases I've actually heard it's better to have a weaker speaker than an amp, as a clipping amp will destroy a speaker much faster than an overdriven speaker. If you are driving the sub constantly to the level of clipping, it could easily destroy the ouptut stages of the amp from running it under almost no load.

Voice coil config can change what load your amp sees. If you have a 4 ohm SVC you are fine as it will always be a 4 ohm load, but if you have a 4 ohm DVC you can wire it in series = 8 ohm load, or you can wire it in parallel = 2 ohm load.

Say you wire it at 2 ohms your amp will now be seeing a 2 ohm load. In comparison to a 4 ohm load the amp will now put out twice as much power into your sub as it is driving a lower impedance. (providing your amp can handle that load; if it cant handle that load it will most likely go into protection)

But if it is setup right and you are aware of what load the amps are seeing, what power your amp puts out then, what your speakers can handle and make sure the gains have been matched correctly you'll be fine. Most importantly listen to clipping and dont ask more than your gear can provide.


Oh ok, i already have this understanding, i thought that maybe there was another issue with DVC subs that i didnt know about.

I have also found that power output ratings on amps can sometimes be misleading. For instance, my brother has a Boss audio 4ch that is supposed to be 100watt RMS per channel. Now I have an Infinity Reference 4ch that reckons its rated at 97watt RMS. Now, my system can be at least twice as loud as my brothers system, his gains are set to max. Mine are only set 1/4 of the way. Go figure.

Quality is everything.

Bit off topic but my 2c anyway.

thanx every one, ive learnt an expensive lesson, i knew about the dangers of clipping, but i just didnt realise that i was doing it, and how easy it was, i guess i just got carried away when turning it up too loud.
mmm not sure on the voltage output tho

it only over heated let it cool