Rsd 12 smelling burnt on only 300 rms?

[lukeman269]

I just got the sub yesterday and I have it hooked up to my Directed D600 running at 2 ohms at 300 rms. I did have the bass boost on when I was smelling the sub burning. The gain was only at about 65 percent as well. I wouldn't think this sub should be burning. I was wondering if I have to wire it differently? I currently have the sub running parallel. I have coil 1 hooked up to the amp and ran wires accordingly positive to positve and neg to neg. I was wondering if I had to hook it up where coil 1 positive running to the amp and coil 2 neg running to the amp and then pos. to pos. and neg to neg. Or would that not even make a difference? I have also heard of underpowering the sub will blow the sub before overpowering it will. So should I get a better amp? Any help is appreciated thanks.

[Bfowler]

sounds like you have it wired up right.

like this:

• is the sub distorting?
  
  the smell could be glue burning as it breaks in which is fine. if the sub is distorting something needs fixing

[lukeman269]

Yep that's how its hooked up. It wasn't distorting but the glue burning could have been what that was. Thanks man! Ya learn something new everyday!

[ttocs]

You can blow an amp from too little power just as you can from too much. Make sure it is staying clean and not clipping.

[stipud]

One of my most pasted links: http://www.bcae1.com/2ltlpwr.htm

[ttocs]

ah wow. As an installer I saw many many subs blown when they were just hooked up to deck power. I mean it was not like once or twice, but once or twice a month while I was working.

[Stryker]

ah wow. As an installer I saw many many subs blown when they were just hooked up to deck power. I mean it was not like once or twice, but once or twice a month while I was working.

What kinda customer hooks any sub up to deck power??? A 16 year old perhaps?

[ttocs]

you would be amazed what would come in the door. Normally proud as a peacock, lookey what I did! But if that article was true there would be no way a deck should ever blow a subwoofer right? myself and any other person working in the industry has seen it happen.

[lukeman269]

You can blow an amp from too little power just as you can from too much. Make sure it is staying clean and not clipping.

How do I know if its clipping or not? Or is that the same as distortion?

[Bfowler]

distortion is a by-product of clipping.



lets say your amp is 300rms

imagine a sine wave on a graph that that goes from 300 to -300

the sine wave starts small, and as you increase your volume gets closer to that 300 peak mark.

if you drive it past that rather then increase the size of the graph, it starts cutting (or clipping as it were) off the tops of the waves. until instead of a smooth sin curve, it actually resembles a square

(img from bcae)





basic geometry tells us that a square has almost twice the area of a circle of the same width/diameter

so a clipped wave is pushing almost twice the power to the speaker. the distortion you hear is the sub trying to play a "square" wave.



to summarize. it isnt really "too little" power that blows speakers.

its trying to get a amp with not enough power to perform like one that does have adequate power, that kills speakers.

[Jacampb2]

Yes, it is a myth that you can blow a sub by under powering it.
Assuming AC supply before clipping, it is just not electrically possible! A sub is a linear electric motor. There are basically two ways it can fail, by exceeding the mechanical limits of the motor and suspension (over excursion), and by exceeding the thermal limits of the of the motor. The thermal power dissipation is directly related to the input voltage and resistance of the voice coil. The thermal limits are typically set by voice coil former material, voice coil wire gauge, resin characteristics, and mechanical cooling design.

Under powering a driver means you are supplying it less input voltage, which in turn means less current, which means less thermal power dissipation. So, you cannot reach the thermal limit by under powering.

The same thing applies to exceeding the motors mechanical limits. The magnetic field generated by the voice coil causes the motor movement. The amount of travel is directly related to the strength of the magnetic field created, and the magnetic field's strength is proportional to the current in the voice coil. Lower input voltage equals lower input current (ohm's law, the coil resistance stays the same) and lower current equals less driver movement, it is impossible for the motor to exceed its mechanical travel when it is under powered.

There are other ways a driver can be destroyed, clipped AC as mentioned, straight DC supply, mechanical damage to the motor alignment or suspension, and adhesives failing just to name a few.

I worked as an installer for about 4 years back in early 2k, I have never seen a speaker blown from under powering it. I have also never seen a sub hooked up to the internal amp in a HU, so maybe we have a bit sharper crowd around here, or maybe the clients were smarter back then... My guess is, that if someone claimed they under powered a speaker to death, that they blew the speaker some other way and were trying to cover it up or they were just to stupid to know what they did.

Later,
Jason

[ttocs]

oh sure then what ever. Half the crowd here still thinks that the multi-meter way is the best way to tune an amp too ..... I have seen many many speakers that had advertised a whole shit load of power, that were blown by either factory or even and aftermarket deck. Now I am know that you guys have much more experience as an installer to tell me that it has never happened or that my customers were dumber then yours but that is just not the case is it? If this were true then it would just never be possible to blow a good set of 6 x 9s from a deck power, let alone any kind of woofer but I just love to lie to you guys, it has never ever ever ever happened unless it was some kind of freak of nature that only seems to happen to the costomers that come to my shop.

Who is the person that typed that article tom? I see no name attached to it to back it up and was just wondering who said this? I do not base my thoughts on a random internet post that anyone can type. I have seem people link to articles to explain why they took a 12v non-rechargable flashlight battery and hooked it up to their power wire like a cap to keep their headlights from dimming. Turns out it was written by a software engineer that was just too smart for his own good. I base my posts on personal experiences and I have seen many many decks blow speakers advertising that they could hold much much more power then the deck was ever able to put out. Can't tell you how many blown high power 6 x 9s I have replaced that just could not have blown according to this article.

[gridracer]

I can tell you as an installer for 15 years I saw lots of speakers blown because of not enough power output on the amp so the owner cranks the gain up all the way and drives the speaker into distortion resulting in a burnt voice coil. Happened weekly where I worked. Now me I always had double the power my subs recommended and gains turned down and never once have I burnt a voice coil on a sub. So in theory no too little power might not blow up the speaker BUT the idiot with too little power cranks up the gains and overdrives his speaker,clips the signal and burns the coil and that is where the too little power blowing speakers "myth" comes from. In closing too little power was still the cause because of a idiot behind the controls. I also have seen guys blow 6x9's off of deck power 50x4 which is really like 16x4 RMS blowing up a 100 watt RMS speaker? how does that happen if too little power didn't cause it? Its because of an idiot trying to play it louder thgan the amp can safely play it.

[stipud]

I'd bet a half decent subwoofer could even thermally dissipate a clipped AC signal or a few volts of DC even...

They probably threw shit on top of the woofers or pushed them in while they were playing and shorted out the voicecoil somehow. If they were dumb enough to run a sub on deck power they are dumb enough for everything else too (not that I didn't try the same thing when I was 16 ).

[ttocs]

again, who wrote that article?

I would dare to say I have replaced more speakers for too little power then because they were honest-to-god overdriven from power. I will always throw 2x the rated power at a speaker before I will give it half the rated power if I had my choice...

[gridracer]

No one will ever convince me that too little power will not blow a speaker. I have seen it too many times. Over 15 years I have probably installed 500 speakers in cars off deck power, and I have seen lots come back with blown speakers if not from too little power than what? they aren't pushing on them while playing in the doors or putting stuff on top of them. I guess me and ttocs just don't install properly or we both had the same supplier for speakers and they were a bad batch.

[Bfowler]

as jacob mentioned, its scientifically imposable to blow a sub on too little power

we are just arguing over semantics though.

the initial problem is too little power. they want more volume then their speaker makes on the given amps unclipped power. so the keep turning it up, the amp clips, and produces more unclean power. and the sub frys from trying to play clipped waves (which have almost 2 times the voltage as unclipped)

so the initial problem is too little power.

but the specific reason the sub fails is more voltage then it can dissipated...or too much power.




its sort of like the argument that every car accident is caused by excessive speed given the situation

[Bfowler]

i just thought of a way to further elaborate on that analogy.


what about the question "a car is going 100mph and crashes. did it crash from "too much", or "not enough" performance?"

one answer could be "not enough performance" the car wouldn't have crashed if it had better brakes/suspension/tires etc

the other side would say "too much performance" if the car was slower, it couldn't have been pushed to the point of crashing.


so both are technically right.

[ttocs]

ok, if this is some cute semantics thing to look smart or something then great, enjoy the joke. But what what the average DIY'er gets from that article, or the phase that it is scientifically impossible to blow a speaker from too little power is that they are never going to blow a speaker such as a high power 6 x 9 or a small woofer with their deck. That is wrong in every way I don't care how you want to turn it around.

What I say is that you are just as likely to blow a speaker with too little power as you are with too much power. If this really is a semantics thing then it is the funniest piece of audio snake-oil I have heard yet to date and I see no reason behind it.

[eulogious]

Who is the person that typed that article tom? I see no name attached to it to back it up and was just wondering who said this? I do not base my thoughts on a random internet post that anyone can type.I have seem people link to articles to explain why they took a 12v non-rechargable flashlight battery and hooked it up to their power wire like a cap to keep their headlights from dimming. Turns out it was written by a software engineer that was just too smart for his own good. I base my posts on personal experiences and I have seen many many decks blow speakers advertising that they could hold much much more power then the deck was ever able to put out. Can't tell you how many blown high power 6 x 9s I have replaced that just could not have blown according to this article.

again, who wrote that article?

ok, if this is some cute semantics thing to look smart or something then great, enjoy the joke. But what what the average DIY'er gets from that article, or the phase that it is scientifically impossible to blow a speaker from too little power is that they are never going to blow a speaker such as a high power 6 x 9 or a small woofer with their deck. That is wrong in every way I don't care how you want to turn it around.

Wow, you seem so bent on learning the sources to "prove" your point that they are wrong, yet you fail to mention ANY facts/legitimate sources to support your argument AT ALL. Tom, Jason, and Brain have not only present FACTS that can be proven by methods accepted by the scientific community, but also supporting scenarios that would backup the FACTS that they presented. You have yet to supply any sort of proof or facts that under powering a speaker will blow it other than your "personal experiences". But yet you insist on saying they are wrong? Based on what, non provable personal experiences? Not much of an argument.

Let me ask you this, and anyone else that insist that you can blow a speaker with too little power, Did you ever test scientifically before AND after replacing the "blown" speaker for ANY other reasons that it could blow? Did you test the car before touching it to get a base reading to make sure that direct DC wasn't coming from the deck or to make sure that there was absolutely NOTHING else wrong with the car before you installed anything? What about after installing it? Did you test the speaker to make sure that it had NO factory defects before installing it? Did you document all this at the time and then have a co-worker go over your test, recreate them and get the exact same results? Because you can do that with a speaker and prove that it WILL NOT fail under any test when operated under normal, controlled, factory recommended conditions, even with low power. This is a fact that can NOT be proven wrong.

If you answer no to any of those questions then there is no way that you can argue against facts that have been presented. Seriously. Get some facts/test/sources to prove that under powering a speaker will blow it, otherwise you are just spouting out your opinion, and we all know what opinions are like

I can't stand seeing an argument that is so non factual from one side it's stupid. Personal experiences are great, but unless you can prove them or that they happened, they mean absolutely nothing to anyone else but you. Facts on the otherhand...

Edit: Corrected Jason's name, my bad!

[holmis]

I have worked in the Audio-video industry for about 15 years... This is what I have experienced both with car stereo & home audio,

The most common cause of blown speakers comes from underperformed amps.
When you blow a speaker with a underpowered amp, you usally (not always) get a speaker with noice (Coocked woicecoil that rubs the magnet).
When you blow a speaker with to much power, usally you can see the voicecoil has got hot over a longer period of time & the coil get dark colored & black due to high temp.
Have seen this a lot on Cerwin Vega home speakers. Young guys dont have money to by a deacent amp, the result is usally blown Tweeter & mids... sometimes the sub too. When they get more money & buy higher Q amps with more power, the tweeter & mids rearly blows, but the subs get burned ...

The clue is how "pure" the power you send to the speakers is...

...

[eulogious]

The clue is how "pure" the power you send to the speakers is...

...

to summarize. it isnt really "too little" power that blows speakers.

its trying to get a amp with not enough power to perform like one that does have adequate power, that kills speakers.

Exactly

[Jacampb2]

Look, I can see how you would arrive at that conclusion, with the scenario that you are now giving us, but it is still not too little power, the root cause is the user trying to get more output than what amplifier in question can provide by driving the amp into clipping and driving the speaker with what amounts to nearly DC input.

No offense intended, but physics and electrical laws, not some obscure theory and creative guesswork, say that this is impossible. Do the math and see for yourself. What do you think happens when you turn the volume down? Do you think your amplifier puts out the rated amount of wattage all the time that it is on?

Tell you what, I will happily test out this myth. I will power one of my xmax 8's with one of my backup HU's in the shop. I will measure the HU output and get a rough idea of what kind of power it is putting out, but I highly doubt it will do over 16 watts or so. You tell me how long it will take to blow being underpowered and I will put my speakers on the line. What do you say?

**edit** Oh, and BTW, I am Jason, not Jacob

Later,
Jason

[eulogious]

**edit** Oh, and BTW, I am Jason, not Jacob

Later,
Jason

Sorry about that, I was just dealing with a Jacob on another forum and it just carried over, my bad

[gridracer]

If you read my first post in this thread I explain exactly how people blow speakers with too little power. Its exactly what you guys are saying.