# Burning smell when I turn it up.



## Texas_Ace (May 24, 2007)

Ok, i have noriced this a few times. I will be listening to my system and i will turn it up and almost instantly i will start to smell a burning smell.

Not like a on fire smell but like when you use a new drill for the first time smell. What i want to know is where is it coming from? The speakers? the amp? the HU?

The amp is an A/D/S/ 6.25 
the speakers are some cheap efx componets
and a Alpine HU.


My guess is that it is the speakers but why would they be doing that?


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## Hillbilly SQ (Jan 26, 2007)

i'm gonna blame either the passive crossovers or tweeters. i had that happen with a pg xenon component set.


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## Oliver (Jun 25, 2007)

Texas Ace, do a search for "clipping".

You might be burning the varnish off of your voice coils.

When clipping occurs, there are some hard to handle watts produced.

Start looking for some more speakers, just in case !


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## tcguy85 (Oct 29, 2007)

probably come clipping.


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## demon2091tb (May 30, 2005)

Or glue thats melting off the vc assembly or inside the passives.......If you get Grey smoke then theres a problem.......


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## solacedagony (May 18, 2006)

Hic said:


> When clipping occurs, there are some hard to handle watts produced.


Watts are watts, there's just more of them


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## Thumper26 (Sep 23, 2005)

lol, true, but the "more of them" part is the issue.


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## Oliver (Jun 25, 2007)

Manville Smith on "What's that smell"  

100 watts of power (twice the heat as a sine wave).

Music has a significantly higher crest factor than sine waves or square waves. A highly dynamic recording (Sheffield Lab, Chesky, etc.) typically has a crest factor of 20dB or more, meaning that its average power is 100 times lower than its peak power. So, if we play our 100 watt amplifier just below clipping with the typical audiophile recording our speaker is only needing to dissipate 1 watt of average power over time.

Modern commercial recordings typically exhibit crest factors of around 10dB, meaning that the average power is 10 times lower than the peak power. So, our 100 watt amp just below clipping would deliver an average power over time of 10 watts that the speaker has to dissipate.

Okay, so what happens when we clip the amplifier (which we all do at times). When the amplifier enters into clipping, the peak power no longer increases, but here's the KEY... THE AVERAGE POWER CONTINUES TO INCREASE. We can often tolerate a fair amount of clipping... as much as 10 dB or more above clipping with a reasonably dynamic recording... a bit less with a compressed commercial recording.

So, if we turn the volume up 10dB higher than the clipping level with our Sheffield Lab recording, we have now reduced the crest factor of the signal reaching the speakers by 10dB... so instead of needing to dissipate 1 watt average, we are asking the speaker to dissipate 10 watts average, and we're probably ok.

If we turn up the volume 6dB past clipping on a compressed commercial recording (or bass music recording), we have taken the crest factor of the signal from a starting point of 10dB to only 4dB, asking the speaker to dissipate an average power of 40 watts instead of 10 watts... that's FOUR TIMES the average power, which generates four times the heat.

SO, in most cases, the reason clipping can damage a speaker really has nothing to do with anything other than an increase in average power over time. It's really not the shape of the wave or distortion... it's simply more power over time.

When someone plays Bass Mekanik clean (unclipped) on a 1000 watt amplifier the average power is 100 watts (10dB crest factor). You can also make 100 watts average with Bass Mekanik by heavily clipping a 200 watt amplifier.

If someone is blowing a woofer with 200 watts of power due to a lack of restraint with the volume control... they will blow it even faster with a 1000 watt amplifier because they will probably turn it up even more and now they have more power to play with... this is the recipe for aroma of voice coil.

When woofers are rated for power, an unclipped signal is assumed. We use test signal with a crest factor of 6dB for power testing and can run a speaker at its rated power for hours and hours on end without thermal or mechanical failure. For example, a W1v2 can dissipate 150 watts average power for eight hours or more with signal peaks of 600 watts. So, we rate the speaker for 150W continuous power. This way, when a customer needs to choose an amp for it, they will hopefully choose one that can make about 150 W clean power... Even if they clip the bejeezus out of that amplifier, it is unlikely that the speaker will fail thermally. This is a conservative method, but it needs to account for the high cabin temperatures in a car (think Arizona in the summer) which significantly impacts heat dissipation in the speaker. A top plate that starts at 150 degrees F is not as effective at removing heat as one that starts at 72 degrees F in the lab... and this affects the ramp up of heat in the coil.

DISCLAIMER: The frequency components of clipping can affect tweeters due to their low inductance and lack of low-pass filtering. Clipping essentially raises the average power of high frequencies to a point that can damage tweeters... Woofers and midranges couldn't care less about these high frequency components because their filtering and/or inherent inductance knocks that stuff out of the picture.

Best regards,

Manville Smith


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