Things some of you should know if you don't already.

chakabobo18

There is nothing wrong with Pok's 2004 or 2005 line up, it's the people who don't know how to set there amp's gain to match the output voltage coming off the back of the head unit from the pre amps that destroy these subwoofers. The RMS of a name brand subwoofer is stated in plain english for one simple reason, and that is because it is the maker telling the consumer to not exceed the RMS limit, because continuous exceeding of the limit will eventually cause damage to the sub. How long it takes to damage the sub, all depends on how much power is being used in excess of the RMS limit.

If that isn't the problem, then you may want to start observing your electrical systems power source not the battery , but the battery's power source, the alternator. If you alternator isn't supplying your vehicles electrical system with enough amps to compensate for how many amps your amplifier(s) are drawing, then you will starve the amplifier(s) of the power it needs to supply maximum power to the subwoofers, forcing the amplifier to compensate for the lack of DC voltage with AC voltage. This will rip any car audio subwoofer on the market apart no matter how strong it is.

neomagus00

your first paragraph is mostly good... the only thing 'wrong' with the lineup is that the subs handle their RMS, but that's it, they don't take more like people expect them to.

your second paragraph is good up until the bit where you speak of compensating for DC with AC... what does that mean? if the alternator can't provide enough juice, the amp will simply not put out as much power; if the amps were properly set to begin with, clipping will be minimal if it exists at all. if there's a large enough voltage drop that major clipping is occurring, the entire car will dim and you know something is very wrong. That clipping will tear apart a sub; i don't know what this mysterious AC is...

chakabobo18

Again the subs being able to handle more that their rated RMS all depends on how excessive power is being supplied to them and that goes for any sub. It kinda seems like those people expect way too much of the polk subs, when there aren't differently at all from any other sub as far as the fundamentals go such as max power, rms, etc.

I refer to clipping as also AC voltage, because years ago, I didn't realize that 700 watts of AC voltage was far more powerful that 700 watts of DC voltage. Anyways, I took two 400 rms watt subs and hooked them up to a 700 watt dinosaur home receiver and clipped the hell out of the signal being sent to them.

Point being, car subs come in 4, 2 and 1 ohm, which are designed to handle DC voltage from a battery. If a gain is set too high on a amplifier, the amplifier will try and draw more DC voltage than is supplied, which is why I call it AC voltage because you know as well as I do that standard house sockets output 120 volts compared to a 12-14.4 volt car battery. As long as you have DC voltage going to you amp, you will have very minimal clipping.

It's not like I'm saying this is the technical term for when car audio system is deprieved of DC voltage, but this is more of a term that I use because of my personal experience and how I can relate it to what I've been through.

You are right about one thin, when there is a large enough voltage drop, the light bulbs and head lamps will dim, and the subs will clip; but what do you call the voltage when the the electrical system is dimming and the subs are clipping from lack of DC voltage?

neomagus00

the amp will ALWAYS get DC voltage, the car has no other way to make power. and you have AC and DC mixed up a bit. a standard waveform is entirely AC. clipping changes some of that into DC, and at maximum clipping, ALL of the power a sub recieves is DC. also, as i think you know, more clipping translates to more power dissipation across a sub. the extra power wouldn't be so bad, except that the sub has reduced cooling capabilities when it's getting a highly clipped signal (slightly, but it does make a difference), and it's the extra power plus less cooling that melts VCs.

chakabobo18

Originally posted by neomagus00
the amp will ALWAYS get DC voltage, the car has no other way to make power. and you have AC and DC mixed up a bit. a standard waveform is entirely AC. clipping changes some of that into DC, and at maximum clipping, ALL of the power a sub recieves is DC. also, as i think you know, more clipping translates to more power dissipation across a sub. the extra power wouldn't be so bad, except that the sub has reduced cooling capabilities when it's getting a highly clipped signal (slightly, but it does make a difference), and it's the extra power plus less cooling that melts VCs.

Ok how about this, when the car system is being deprieved of oxygen, the DC voltage isn't pure, therefore leading to clipping and as you said, a bit more power minus some cooling potential with the voice coils, eventually leading to burning of them out.

neomagus00

yes, except the DC voltage is still pure, there's just less of it.

MacLeod

My $.02:

An amp will always get DC.

If an amp is not getting enough voltage, it puts out less power and eventually shuts off and puts out nothing.

Car system being deprived of oxygen? Lost me on that one.

As far as subs handling power it all depends on the manufacturer. MTX makes virtually indestructible subs. My little 8" is a 150 RMS sub yet its been getting nearly 400 for the last 8 months or so without a problem. Youre right tho that a good rule of thumb is to stay within rated power handling.

Clipping doesnt hurt speakers. A speaker doesnt know the difference between a clipped and round signal. When an amp clips it sends out a signal usually double its rated power and its the exess power that kills the sub. Example: Take a 500 watt sub and hook a 100 watt amp to it. You can push it to clipping all day long and twice on Sundays and the sub will never even whimper because even tho the amp is clipping, its only sending out 200 watts which is well below the subs limits.

And as far as I know, 700 watts is 700 watts regardless of its source. Thats like saying 100 pounds of metal is heavier than 100 pounds of wood.

neomagus00

Originally posted by MacLeod
Thats like saying 100 pounds of metal is heavier than 100 pounds of wood.

you mean you don't remember the elementary school joke, "which is heavier, a pound of rocks or a pound of feathers?", and EVERYONE got it wrong the first time?

chakabobo18

Originally posted by MacLeod
My $.02:

An amp will always get DC.

If an amp is not getting enough voltage, it puts out less power and eventually shuts off and puts out nothing.

Car system being deprived of oxygen? Lost me on that one.

As far as subs handling power it all depends on the manufacturer. MTX makes virtually indestructible subs. My little 8" is a 150 RMS sub yet its been getting nearly 400 for the last 8 months or so without a problem. Youre right tho that a good rule of thumb is to stay within rated power handling.

Clipping doesnt hurt speakers. A speaker doesnt know the difference between a clipped and round signal. When an amp clips it sends out a signal usually double its rated power and its the exess power that kills the sub. Example: Take a 500 watt sub and hook a 100 watt amp to it. You can push it to clipping all day long and twice on Sundays and the sub will never even whimper because even tho the amp is clipping, its only sending out 200 watts which is well below the subs limits.

And as far as I know, 700 watts is 700 watts regardless of its source. Thats like saying 100 pounds of metal is heavier than 100 pounds of wood.

Damn I had just wrote a page worth of information and accidently closed the window, so I'll just make this long story short........I agree with you on the DC voltage now that you refreshed my memory on what happens when you don't get enough voltage.

What kind of amp are using to power the MTX? I can tell you right now that now all amps are made alike, obviously one reason is because of the voltage used to rate the amp's power it the same with every maker, but I'm refering to companies who falsely advertise their products.

When I said oxygen, I was referring to DC voltage. I just was relating DC voltage and the amplifier to us and oxygen.

After very briefly thinking about it, it wasn't the AC voltage that tore my subs apart, it was actually the load that my subs demanded from the receiver that tore them apart. A 2 ohm sub places twice the load on a amplifier as a 4 ohm sub right? Correct! Well home receivers are typically rated at 8 ohms or 6 ohms. So when I took my receiver with its power rated based on a 8 ohm load and hooked up a 4 ohm subs to it, correct me if I'm wrong, but I think receiver tried to double it power, which only resulted in it shreding the hell out of my subwoofers.

MacLeod

First off let me just say, HOW DARE YE CHALLENGE THE POWER OF THINE CROSSFIRE!? Crossfire amps are among the most powerful amps on the planet. Thats why I chose them. They are also among the most ridiculously underrated amps as well due to the fact that they are competition level amps. The VR302 Im using on my MTX is rated at 300x1 but I guarantee you its putting out every bit of 350-400! Every Crossfire amp Ive ever seen in magazines has exceeded its ratings by 40-50%! Hmphf! Question my Crossfires. Double hmphf.

If you ran a 8 ohm receiver at 2 ohms you would be more likely to shred the receiver than the subs. Also amps dont necessarily double their power as impedance drops.

There are only 3 things that kill speakers.
1- over extending the suspension by forcing beyond its limits with too much power
2- too much heat being built up in the voice coil faster than it can dissipate it usually by too much power.
3- poking a screwdriver thru the cone.

chakabobo18

Originally posted by MacLeod
First off let me just say, HOW DARE YE CHALLENGE THE POWER OF THINE CROSSFIRE!? Crossfire amps are among the most powerful amps on the planet. Thats why I chose them. They are also among the most ridiculously underrated amps as well due to the fact that they are competition level amps. The VR302 Im using on my MTX is rated at 300x1 but I guarantee you its putting out every bit of 350-400! Every Crossfire amp Ive ever seen in magazines has exceeded its ratings by 40-50%! Hmphf! Question my Crossfires. Double hmphf.

If you ran a 8 ohm receiver at 2 ohms you would be more likely to shred the receiver than the subs. Also amps dont necessarily double their power as impedance drops.

There are only 3 things that kill speakers.
1- over extending the suspension by forcing beyond its limits with too much power
2- too much heat being built up in the voice coil faster than it can dissipate it usually by too much power.
3- poking a screwdriver thru the cone.

So what do you think destroyed my subs?

My bad on the Crossfire amplifier, it falls into the same category then as my Hifonics amplifer, because not a lot of people know about them, and if they do, they don't think much of it. My I too feel that my amplifer puts on more that its 1500 watts rms. I say this because my sometimes it has my H2 hit so hard and extending the suspension so far on my sub, I think that the cone itself is going to separate from the surrounding rubber.

MacLeod

Crossfire is better than Hifonics!

But youre right, Hifoincs is a competition level amp as well and is likely well underrated.

I dont know what blew your subs. What equipment were you using and at what power ratings? How did you have them hooked up? What kind of subs were they?

chakabobo18

Originally posted by MacLeod
Crossfire is better than Hifonics!

But youre right, Hifoincs is a competition level amp as well and is likely well underrated.

I dont know what blew your subs. What equipment were you using and at what power ratings? How did you have them hooked up? What kind of subs were they?

As far as your amp being better than mind, that's just a figment of your imagination.

I had a older model receiver from back in the 80's, freakin huge receiver, it must have weighed about 30-40lbs. 700 watt receiver, because the receiver was so old, it didn't say if that where rms or not, to my knowledge, but then again this was years ago when I first started showing interest in car audio, so back then I might not have known was rms was.

LittleCar_w/12s

Chak:
First off, I must ask what brought the onslaugt of vindictory information you have bestowed us?

Secondly, you have a few correct points on the ac point being reached in an automobile they are:

When the battery is so low on charge that the alternator's AC rectified to DC output is no longer filtered by the battery. You hear this as alternator whine, etc.
-- Note here that ANY well built amplifier whether in the deck or the sub-amp will have huge capacitors in them that eliminate this noise. Therefore this is not an issue to a good peice of equipment.

iIf the mean voltage of the electrical source (car) is lower than usual, the amp will have a lower mean voltage at it's start and therefore a significantly lower voltage in the output of the power stage. While the in-between of this is actually purposely made into AC to go through the transformer, it will always be DC on the other side. What creates the clipped signal is the output voltage is so low that the original gain settings become too high and are now out of adjustment.
-- Note here that this essentially reduces the output of the amp, no matter what, no way around it... the amp is not giving out more power now that it is clipped due to low source voltage....

With that said, having not enough power in your system cannot blow up a sub or any speaker, what can blow them up is not properly adjusting the system.


Note this as well. When you set up a car system's levels while running and they are peaked out it will almost definitely sound like crap when not running due to power decrease; but if you peak your output while it is not running you will have to mathematically factor out what the output will be when it is lest you eat a speaker. The easiest solution is buy an amp with more power than you need and simply use a little less, but this takes self-control.


Therefore it seems there to be only three reasons for blowing up a speaker:
Stupidity or ignorance as to how to set up a system,
Genuine component failure (speaker or amp),
Or simply being a jackass.

Which one did you do?

chakabobo18

Originally posted by LittleCar_w/12s
Chak:
First off, I must ask what brought the onslaugt of vindictory information you have bestowed us?

Secondly, you have a few correct points on the ac point being reached in an automobile they are:

When the battery is so low on charge that the alternator's AC rectified to DC output is no longer filtered by the battery. You hear this as alternator whine, etc.
-- Note here that ANY well built amplifier whether in the deck or the sub-amp will have huge capacitors in them that eliminate this noise. Therefore this is not an issue to a good peice of equipment.

iIf the mean voltage of the electrical source (car) is lower than usual, the amp will have a lower mean voltage at it's start and therefore a significantly lower voltage in the output of the power stage. While the in-between of this is actually purposely made into AC to go through the transformer, it will always be DC on the other side. What creates the clipped signal is the output voltage is so low that the original gain settings become too high and are now out of adjustment.
-- Note here that this essentially reduces the output of the amp, no matter what, no way around it... the amp is not giving out more power now that it is clipped due to low source voltage....

With that said, having not enough power in your system cannot blow up a sub or any speaker, what can blow them up is not properly adjusting the system.


Note this as well. When you set up a car system's levels while running and they are peaked out it will almost definitely sound like crap when not running due to power decrease; but if you peak your output while it is not running you will have to mathematically factor out what the output will be when it is lest you eat a speaker. The easiest solution is buy an amp with more power than you need and simply use a little less, but this takes self-control.


Therefore it seems there to be only three reasons for blowing up a speaker:
Stupidity or ignorance as to how to set up a system,
Genuine component failure (speaker or amp),
Or simply being a jackass.

Which one did you do?

Hmmm.......lets see

Thanks for clearing up the AC situation, which I didn't quite have a full grasp on. I knew that AC voltage did exist at some point in the electrical system. but not exactly where.

Replacing the amp with a more powerful and using less power might be the easiest solution, that will only work for experienced people. The ultimate and safest solution is still to replace the alternator, because you can never have to much power.

You know there's no need for profanity up in my thread, after reading your post, I'd say that you seem like a intelligent person, so I'm sure that you can use that intelligence of yours to come up with more creative words than jackass.

Just to clear up any misdirection from the last paragraph, I'm not saying, I don't have an answer to your question, look at it more like I'm not trying to get kicked out of the Polk forum for responding to your question on your level.

MacLeod

LOL!! Wait til you meet Jstas!

AustinKP

wait...Jackass is profanity? As the others can attest, I never swear, but even I will use jackass
Anyway, in a nutshell, what was the point of your posts? I read them, but I don't understand what you're getting at. Especially since, as you admitted yourself, you don't firmly have a grasp on everything you're saying.
-Austin

bknauss

Originally posted by chakabobo18
Ok how about this, when the car system is being deprieved of oxygen, the DC voltage isn't pure, therefore leading to clipping and as you said, a bit more power minus some cooling potential with the voice coils, eventually leading to burning of them out.

You always get DC voltage. What happens is that the alternator can't provide enough current, so the voltage drops. Its still DC, just not as much as before.

chakabobo18

Originally posted by AustinKP
wait...Jackass is profanity? As the others can attest, I never swear, but even I will use jackass
Anyway, in a nutshell, what was the point of your posts? I read them, but I don't understand what you're getting at. Especially since, as you admitted yourself, you don't firmly have a grasp on everything you're saying.
-Austin

chakabobo18

As I titled the thread, "things you should know if you don't already," meant that you go in and post things you know, learn or have experienced. In my case, I put why I knew, which was somewhat inaccurate, which is totally find, I enjoy learning what I don't know. So there didn't really have to be any point to the threads.

But you can't tell me that you didn't understand what I was getting at because you went to into further detail, on why had heard by word of mouth, which lead me to a deeper understanding of what I was trying to say.

Isn't that what this forum that Polk has bestowed upon us is all about, even better, isn't that was this thread is about?

For you see I may not have saw the full picture just as you did, but I do personally know how to avoid that situation.

In one of my threads I talked about blowing two subs, yeah well that was roughly 5 years ago when I first started to show interest in car audio.

The point of this post is we all will put information on the forum that is somewhat inaccurate, but their will always be someone to come along and correct that person. :cool:

So what do you think of your Hifonics amplifier?
Does that secondskin stuff actually work?

chakabobo18

It is just my computer of do any of you guys and girls not see my profile signature?

neomagus00

it only shows up on your first post in a thread.

and i don't know personally about hifonics, but it's described as 'competition quality' by some... and it was good enough for pimp my ride...:rolleyes:

and yes, secondskin is amazing stuff. milspec for heat, too, which is very tasty.

chakabobo18

What is a relay? What is the point of using them or the benefit of having them?

spwuinmk67

Hey neo, I think I saw something about Secondskin being on Pimp My Ride, also. I didn't know Hifonics was until I watched it at work today. Spinner grilles?!?!

AustinKP

Originally posted by chakabobo18
So what do you think of your Hifonics amplifier?
Does that secondskin stuff actually work? [/B]

I love my HiFonics amp. It puts out its rated power and does so very cleanly. For the money, I don't know that it can be beat. I paid $220 for mine shipped.
The SecondSkin Spectrum has made a noticable difference in the noise in my trunk, and I'm only halfway done so far. I still have another gallon to paint in. I've never used another dampener, so I have nothing to compare it to, but this has worked well for me. -Austin

neomagus00

spunky: i didn't actually watch it, i saw it on hifonics' site... i can't stand that show...

chakaka: a relay uses a small input signal to close or open a switch that passes much more power. they're used on things like many-amp setups to turn all the amps on - the HU can't supply all 15 amps off one remote lead, so you run the remote lead into a relay, and through the other side of the relay you run way more voltage, say 2 V instead of 0.2... the HU's remote lead flips the relay, allowing the power to hit the amps, turning them on.

basically any time a small current needs to activate something big... motorisation is a common one too.