sub is smoking

I Got a Sony XM-1252GTR 2/1 Channel in Brige mode at 340 watts/ 800Watts Max to a pionner premier 12" sub 400watts rms/ 1200max
And Afther like two minute smoke was coming from the vent of the enclosure. I dismount the sub to see it was coming from the magnet
how is this possible my amp is not that strong??

You are mismatched. It sounds like you are expecting more than your system is capable of providing, and you have misadjusted your amp.

Re-set your gain.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Here's the simplest answer:

Speakers like two things.

1) A.C. signals

2) Voice coil venting

Speakers dislike two things:

1) D.C. signals

2) Lack of venting.

My guess is that the sub was driven into sub-sonic tones or that the amp was overdriven causing the signal to saturate meaning that the sub was getting a D.C. signal too often for too long. It doesn't take much power to do so, a 1.5 volt battery on the coil for a minute would have yielded the same results.

This amp is actually 125 watts according to CEA standards. The lack of sufficient clean power will destroy your sub.

Get an amp that puts out 400 watts CEA and you should be in business (don't forget sub-sonic filtering and box tuning).

BTW, your sub should be in a

Sealed 0.85 - 1.75 cubic feet  or

Ported 1.25 - 2.05 cubic feet

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Big Dog wrote:

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My guess is that the sub was driven into sub-sonic tones or that the amp was overdriven causing the signal to saturate meaning that the sub was getting a D.C. signal too often for too long. It doesn't take much power to do so, a 1.5 volt battery on the coil for a minute would have yielded the same results.

---

That's ABSOLUTELY wrong, on two points. 1: The failure he is describing is electrical, and not mechanical. 2: Unless the TOTAL POWER DISSIPATED EXCEEDS THE ELECTRICAL RATING OF THE WOOFER, the voice coil doesn't give a crap whether the voltage across the terminals is AC or DC. Period.

1.5 volts, across 4 ohms equals .56 watts. That's one-half of one watt. Now, if the woofer (really, ANY driver) is rated for SIGNIFICANTLY less than one watt, .5 watts will NEVER blow ANY speaker. Even connecting a decent 4 ohm woofer across a 12 volt car battery won't blow it, as even at 12 volts that's only 36 watts.

Big Dog wrote:

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This amp is actually 125 watts according to CEA standards. The lack of sufficient clean power will destroy your sub.

---

This is also a complete fallacy. Low power CANNOT damage a speaker. Done and done. We've been over this and over this... Here, read this thread... It explains everything completely.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Then I have nothing more to say.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

thx a lot
I readjust my amp and everything is going well so far

To quote myself, I said:

Big Dog wrote:

---

Here's the simplest answer:

Speakers like two things.

1) A.C. signals

2) Voice coil venting

Speakers dislike two things:

1) D.C. signals

2) Lack of venting.

---

This is the same thing as what is said here: https://www.bcae1.com/2ltlpwr.htm ,"Remember that during the clipped portion of the waveform current is still flowing through the voice coil. Since the displacement of the voice coil (and therefore the airflow around the voice coil) is no longer proportional to the heat being generated, the voice coil can overheat."

An overheated voice coil can burn the schellac off the voice coil wire thus emmitting that undeniable smell that prompted this post to begin with.

You'll notice that I started my first post with the statement : "Here's the simplest answer " wanting to avoid beating a dead horse.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Whenever I catch my subs smoking I smack them upside the head, make them read some literature about lung cancer, ground them for three weeks and take away their Nintendo privileges.

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lol

that's right, you regulate DYohn! Tell those silly subs who's boss.

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RTFM

DYohn] wrote:

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henever I catch my subs smoking I smack them upside the head, make them read some literature about lung cancer, ground them for three weeks and take away their Nintendo privileges.

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So you have to play your Nintendo subless?  Three weeks of Donkey Kong sounding like Minnie Mouse would suck. 

hmmmmmmmmmm never fried any subs lol yet. but i did fry a mtx crossover once. ahhhhhhhh the smell of burnt electronics. sniff sniff brings back memories. i need a moment alone sniff sniff.

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OWWWWWWWWWWW you said you discharged the cap!

OK.... Make note of my signature first........ With that said, what is the CEA Standard, and how do you search it? I'd like to know more about this subect

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The Only Stupid Question, is the one Un-asked

I'm glad you asked.

Here's the article: CEA

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Or... here's a little more info, with links to further information. While the JBL is informative, it's a little bit ...elementary.

Depending on how in-depth you want to get, you can also look to the CEA, this link deals specifically with the measurement of power amplifiers. The entire text is rediculously overpriced at $72.00, but there's where you go to get ALL the answers for that particular question.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

While the wiki is informative, it doesn't outline the CEA standard. For the real deal you need to become a member and shell out the $72. For free, I thought the JBL article was well written in laymen's terms and can easily be understood when comparative shopping - which is what the primary purpose of the standard is - to cut through the marketing mumbo-jumbo.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

I like the Andy Wehmayer article.

Steven, re Donkey Kong.  it's punishment, but I will stop short of torture.  :)

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Want to know more about acoustics and energy? Here's some light reading while on your coffee break. Electrical analogs of physical structures.

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Prepare your future. It wasn't the lack of stones that killed the stone age.