Avalanche 15 Coil Smell at 70 watts?

[matt09 0]

I have been running my Avalanche 15 in an unfinished sonotube for many months on a low wattage amp. I have never been able to really crack it up, but hooked it up to a new Sony PA amp and tried it with sine waves from a computer with the amp turned up full. I noticed after a small while the centre of the cone on the speaker was warm and there was a smell starting to come from the port hole in the magnet.

How is this possible just from 70 watts ???

I can verify it was about 70 watts as I measured the current and voltage which was 4.7 amps, 14.2 volts with load applied.

It would be great if someone could make sense of this.

[fbi90909 0]

with the amp turned up full.

clipping?

[danracer 0]

perhaps the amp could've been clipping.... ohh you beat me to it lol

Edited December 2, 2007 by danracer

[matt09 0]

Yeah, I thought of that already but surley that still wouldn't be enough to make a 1000watt coil hot?

[Jybfan04 1]

Yeah, I thought of that already but surley that still wouldn't be enough to make a 1000watt coil hot?

Clipping can burn any coil if it can generate enough heat..

[matt09 0]

I suppose looking at it, it would be like giving it a DC voltage of 14.2v at 4.7A, but surley this is still nothing compared to the energy input compared to 800-1000 watts. Would the Avalanche be damaged? I didn't let it heat up too much so just a bit of singed coil?

[JimJ 11]

Moral of the story is...use proper amps

[fbi90909 0]

Moral of the story is...use proper amps

x100 thousand 47 times.

i explain it to a lot of people that don't think using a smaller amp can cause damage to a subwoofer. if they properly set the gains it's fine, but if they try to get as much out put from the little amp it's going to cause clipping.

[matt09 0]

Do you think the damage is superficial or will it now be hindered in some way?

[buickid 0]

If it still plays, I think it should be fine.

[johnecon2001 82]

I doubt you damaged it permanently, lucky for you.

Don't do that again though.

[matt09 0]

Yeah, it still plays fine, I don't know how badly the coils being burnt though. I just won't be putting too much power though when i get an amp - I'll probably use a Behringer 1200 watt PA amp which is what most people use with them for a home setup, gains not up too high obv.

[johnecon2001 82]

Yeah, it still plays fine, I don't know how badly the coils being burnt though. I just won't be putting too much power though when i get an amp - I'll probably use a Behringer 1200 watt PA amp which is what most people use with them for a home setup, gains not up too high obv.

How about you actually set the gains in accordance to how much the sub can handle this time?

The proper way is to use an oscilliscope, but since not everyone has one, you can use a DMM as well.

[jearhart 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

my guess is that you finally heated it up enough to get the glue smell a little. i wouldnt worry about it at all

[Duke 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

my guess is that you finally heated it up enough to get the glue smell a little. i wouldnt worry about it at all

Set the gains to how much the amp can cleanly produce.

[jearhart 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

my guess is that you finally heated it up enough to get the glue smell a little. i wouldnt worry about it at all

Set the gains to how much the amp can cleanly produce.

huh?

[Duke 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

my guess is that you finally heated it up enough to get the glue smell a little. i wouldnt worry about it at all

Set the gains to how much the amp can cleanly produce.

huh?

Amplifiers will start to produce a clipped/unclean signal at a certain volume/gain setting where there components can no longer cleanly increase the power. Find out where that will happen on your amp and set it slightly below that point. Clipping really likes to happen when you try and feed more power to say, a 1000 watt sub... but your amp only produces 70 watts. That heats up the coils quickly. Underpowering a sub isn't bad, UNLESS the signal is clipped/distorted/unclean.

I'm not the best at explaining it, especially when my sleeping pills are kicking in.

Edited December 3, 2007 by Duke

[matt09 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

This is what I was getting at from the beginning, I understand the dangers of clipping but on such a low wattage it doesn't make sense. There shouldn't be enough power to make the gague of the wire on the coil become warm.

[Duke 0]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

This is what I was getting at from the beginning, I understand the dangers of clipping but on such a low wattage it doesn't make sense. There shouldn't be enough power to make the gague of the wire on the coil become warm.

Thats how you blow/damage a speaker with low wattage... clip the signal. It CAN and quite possibly will cause that type of damage.

[BKOLFO4 29]

there is no way you damaged the coild on your sub. even if you were sending a full clip the sub would only be seeing 119.49 watts. not nearly enough to damage the coils on a 1000w sub.

my guess is that you finally heated it up enough to get the glue smell a little. i wouldnt worry about it at all

x2.

An amp that normally produces 70 watt RMS, even fully clipped should not be enough to hurt that driver. Clipping is not what hurts the driver - it is the fact that the RMS power can increase theoretically to match the peak power if the output becomes a square wave at the peak voltage without damaging the amp.

If he had a 800-1000 watt amp and clipped it hard enough, there could be damage.

A 70 watt amp clipped hard enough should hurt the amp before it hurts an avalanche.

http://www.forceaudio.com/showthread.php?t=15

"Normalized power was a little more interesting. We could not prove within the scope of our test that a different signals of normalized power would have any different effects on the driver, regardless of the amount of cone excursion. Some people may still argue this, but it seemed pretty clear to us that weather a square or sine was put into a driver at a normalized power level, it still failed about evenly.

An extra test.... Remember when some people say "It doesn't even matter if it is only a few watts, if it's pure distortion, it will ruin your woofers".... Well we took a 10 watt square wave and ran it into a Pioneer 10" subwoofer for a few hours.... Nothing happened to it, of course, the motor didn't even get hot...."

In this test, they showed a driver could be driven with a sine wave or square wave without damage. . .

A woofer does not know if it is receiving distortion or not (heck, most rock music has distortion added anyway, right?). If you are not going beyond the mechanical or thermal limits, it should not hurt the driver.

Maybe if you were clipping it hard enough, the equipment you were using to take the voltage and current readings was not acurate. . .

BTW - I have run the avalanche on 1400 watts in my suburban without any problems.

Brian

Edited December 4, 2007 by BKOLFO4

[matt09 0]

Thanks for all the info, does anyone really have any idea how it actually caused the coil to smell and the centre of the cone to become warm in the end though?

This is the amp I was using here.

As BKOLFO4 is saying and what I have thought all along is that it can't physically happen from such a low output.

I don't suppose it could be that I have bought a dodgy Avalanche that already has a severly damaged voice coil?

- I bought it off a guy who had used it for home audio and assured me it was only used a handful of times but I still don't understand . . .

[sundownz 197]

70 - 100 watts will still generate heat in any woofer.

Less than 1% of the input energy moves the speaker cone in a typical subwoofer.

Ever touched a 100-watt light bulb? It's VERY hot... and thats with a huge air gap and glass in between your finger and the filament. The woofer coil is much closer and directly physically connected to the dust cap, it will get hot without a tremendous amount of power given enough time.

[jearhart 0]

70 - 100 watts will still generate heat in any woofer.

Less than 1% of the input energy moves the speaker cone in a typical subwoofer.

Ever touched a 100-watt light bulb? It's VERY hot... and thats with a huge air gap and glass in between your finger and the filament. The woofer coil is much closer and directly physically connected to the dust cap, it will get hot without a tremendous amount of power given enough time.

this is what i was saying, even though you didnt come close to the limits of your sub, it still heated it up some. when subs are new the glue will heat up and smell, that is normal.

[Fi Car Audio 64]

Wouldnt have figured that given the coil and former size that it would heat up to that extent... Ill have to test with 70W of power to one on the bench and see what the thermal rise time is for it (Do it with DC as it would be a worst case scenario). Easier to test than pulling out the old thermo books...lol

Thanks,

Scott

[johnecon2001 82]

ouch 70w DC is no fun.