On May 4, 10:43 pm, dpierce.cartchunk....@[EMAIL PROTECTED]
wrote:
> On May 4, 3:31 pm, luvpoc...@[EMAIL PROTECTED]
wrote:
>
> > Hi, I just started reading Daniel Levitin's book, "This is Your Brain
> > on Music" and in the introduction he says that in his college days he
> > listened to music at such high volumes that: "I actually set my
> > loudspeakers on fire by cranking the volume too high." Is this
> > hyperbole, or can this really happen? Has anybody here ever
> > experienced this?
>
> The short answer is no, it can't happen.
>
> The long answer is still no.
>
> I have, for a variety of clients, done extreme stress testing
> of loudspeakers to the point of irrecoverable failure under
> a wide variety of circumstances. I have driven voice coils
> to the point of melting the attached domes, to beyond the
> point of boiling the ferrofluid out of the gap, and so on.
>
> In THOUSANDS of cases, there does not exist a single
> case of ANY of them coming remotely close to catching
> fire. In all cases, the electrical system simply opened
> up first.
>
> There was once a high-end store in Harvard Square
> which had a pair of EPI 100 speakers where the center
> of the cone was charred and burned through, and the
> store's claim was that their McIntosh amplifiers were
> so powerful that they set the speakers on fire. A friend
> bought the speakers for $5 as a curiosity and brought
> them buy. The burn pattern was VERY curious, indeed.
> While the cone was indeed burned, as in fire, the voice
> coil itself was perfectly intact and had NO signs of
> ANY thermal stress whatsoever. Further, the speakers
> had their grills, and there was no sign of soot or ash
> in the backside of the grill cloth, even thoughthe cones
> were extensively damaged.
>
> The conclusion was simple: the single case that I was
> able to examine where there was visual evidence of a
> fire was deliberately burned with a torch as a sales
> gimmick.
>
> The reasons it can't happen are many. In most cases,
> the voice coil or the solder joints for the flex leads or
> the power supply caps give up LONG before there's
> enough heat generated to raise the temperature to
> the ignition point of the cone. The voice coil is buried
> in a steel structure that conducts a LOT of the heat
> away. The speakers at that point are sounding SO
> awful by being so several overdriven that they are
> beyond intolerable to listen to. And so on.
>
> It's urban legend, short and sweet.
>
> Now, you want STUPID loud? I once knew a kid
> who would brag about the fact that he would take
> his Phase Linear 700 and hook it to his Bose 901's
> and set them up almost like giant headphones
> and play it SO loud his ears would bleed. He
> though it was WAY cool.
>
> I met him about 5-8 years later and he was a sorry
> young man in his mid 20's who was almost completely
> deaf.
Oh, I dunno...
You are assuming well-made, well-designed speakers that would
generally fail as you describe from being over-driven.
However, here are a few designed-to-fail situations:
http://www.youtube.com/watch?v=TSqy7p--O2c
http://www.youtube.com/watch?v=oNBdWfBgqXk
Sub-woofers are strange beasts - and those designed for vehicles yet
stranger. One needs suspend assumptions when dealing with such
animals. Catching fire from being over-drive would not surprise me at
at all given that the are designed simply _not_ to fail from whatever
abuse as might be thrown at them.
I do remember one "legend" - an AR rep stating that their AR-9
speakers could be plugged into a wall and not sustain damage for at
least ten full minutes. Yeah... right... Imagine that warranty claim.
Peter Wieck
Melrose Park, PA
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