Determining power handling of a speaker ?

[Eeyore]

maybe just "dry lubricant" of fine graphite powder laid in the track area
instead.

That'll change the resistance won't it ?

Graham

 

[Michael A. Terrell]

Oh for heaven's sake guys, it's *force cooled* !

Certain manufacturers have also demonstrated their voice coils operating red
hot, the materials are that good.

Graham

Really? How do they maintain the impedance? The resistance would go
up quite a bit, and the insulation wouldn't last very long. It sounds
like another audiofools dream.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Leonard Caillouet]

Really? How do they maintain the impedance? The resistance would go
up quite a bit, and the insulation wouldn't last very long. It sounds
like another audiofools dream.

I seem to recall some manufacturer in the 1980s demonstrating something like
this, touting the durability of their kapton voice coil formers. I am not
sure that the demo was using actual voice coil wire.

Leonard

 

[Ron(UK)]

Really? How do they maintain the impedance? The resistance would go
up quite a bit,

It does, that`s why power compresion occurs.

and the insulation wouldn't last very long.

probably not, I have seen coil formers baked very brown by the heat
from the coil without the coil itself failing, I doubt the actual voice
coil could withstand glowing red, specially as they are almost always
copper or aluminium. Maybe the term red hot was meant as a
colloquialism for 'very very hot', certainly above 100c

I`m quite prepared to be educated tho.

Ron(UK)

 

[Eeyore]

Really? How do they maintain the impedance? The resistance would go
up quite a bit,

It does ! The effect is usually called 'power compression' and it can typically
knock up to 3dB off the speaker sensitivity with prolonged high power use. That'll
give you some inkling as to the temp rises involved.

Since such speakers are invariably used with 'active crossovers' on the inputs to
the amplifiers it doesn't cause any adverse issues with crossover responses.

The company that first made that 'red hot' claim was Precision Devices. You can
find a 1000W continuous rated speaker of theirs here.

http://www.precisiondevices.co.uk/showdetails.asp?id=17

and the insulation wouldn't last very long. It sounds
like another audiofools dream.

Kapton voice coil formers are now the norm for decent quality speakers.

I have *never* seen a purely thermal failure in any *modern* voice coil.

Graham

 

[Ron(UK)]

It does ! The effect is usually called 'power compression' and it can typically
knock up to 3dB off the speaker sensitivity with prolonged high power use. That'll
give you some inkling as to the temp rises involved.

Since such speakers are invariably used with 'active crossovers' on the inputs to
the amplifiers it doesn't cause any adverse issues with crossover responses.

The company that first made that 'red hot' claim was Precision Devices. You can
find a 1000W continuous rated speaker of theirs here.

http://www.precisiondevices.co.uk/showdetails.asp?id=17



Kapton voice coil formers are now the norm for decent quality speakers.

I have *never* seen a purely thermal failure in any *modern* voice coil.

Graham

I`ve seen the pigtails melt before the voice coil does.

Ron(UK)

 

[Meat Plow]

I`ve seen the pigtails melt before the voice coil does.

Ron(UK)

I'm a musician who plays bass. My rig is a 1000 watt rms Crown
Microtec power amp biamped to a 4x10 cab and 1x15 cab. I caught the Cerwin
Vega 15" speaker on fire at an outdoor gig and didn't even know it until
people in the crowd yelled at me. Prior to that, the speaker was reconed
and I guess the person who reconed it used flammable materials as I'm
pretty sure a speaker cone isn't supposed to catch fire. And since we had
a fire extinguisher hand I was able to put it out right away saving the
cabinet. I measured the voice coil and it wasn't open or shorted. I sent
it back to the local reconer and he redid it for free and promised it
wouldn't catch fire again which it never did.