Members DBR013 Posted May 28, 2013 Members Share Posted May 28, 2013 Hello folk,I have heard about this happening but what causes this? Pushing the speakers over their capabilities I think can be one and can it destroy the rider? Link to comment Share on other sites More sharing options...
Members agedhorse Posted May 28, 2013 Members Share Posted May 28, 2013 If the voice coil gets hot enough, it can ignite the surrounding paper in a pulped paper cone or dust cap. Used to be that with treated paper bobins, those too would ignite.It's fairly rare, but possible. Link to comment Share on other sites More sharing options...
Members Tomm Williams Posted May 28, 2013 Members Share Posted May 28, 2013 In my early days when my head was buried way up my ***, I smoked a set of Carvin boxes. You could literally see the smoke coming out of them. Not sure what went wrong but I was so green at the time it could have been anything. Link to comment Share on other sites More sharing options...
Members dcastar Posted May 28, 2013 Members Share Posted May 28, 2013 Skip to 1:05 for carnage Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted May 28, 2013 Members Share Posted May 28, 2013 In general you will find this happen after an amplifier failure/problem that causes DC across the voice coil. The exact amount will depend on a lot of factors. But essentially what happens is that there is excessive heating allowing for a build of volitle gasses... when the voice coil opens, there is a small spark. If all of the conditions are correct, this small spark will contain enough engery to ignite the gases... and again, if all of the conditions are correct, there will be enough gases to ignite the cone.I have never seen this occur with AC. IME the ignition path (spark-gases-cone) is broken due to the air-flow induced by the cone motion.There are test methods to determine the points at which this could occur (I tech'ed on the research for EIA-636). Link to comment Share on other sites More sharing options...
Members DanBAP Posted May 28, 2013 Members Share Posted May 28, 2013 I was once assisting on a session where the engineer got drunk and passed out at the console with the music looping and the speakers (Adam S3A's) all the way up. The clip lights were just on steady - no blinking. After a little bit, the ribbon tweeters started sparking and smoking, which is when I woke him up. -Dan. Link to comment Share on other sites More sharing options...
Members vort Posted May 28, 2013 Members Share Posted May 28, 2013 Never happened with pro speakers, but when I was around 16, I got a new album for Christmas and decided to give it a listen in my room. The speakers were old woodgrain stereo speakers that were hand-me-downs. As I'm listening to the music, I start to smell something burning. I look over to the speakers, and one is glowing orange. All of sudden a ring appears as the cloth grill starts melting away, then a flame pop's up. Panicing, I turned off the stereo and grabbed a pillow to beat the fire out. Spent the rest of the day cleaning the black soot off of everything in my room, and mourning the loss of my favorite pillow. I don't remember any more what the album was, but when I tell the story, I joke that it was Black Sabbath. Link to comment Share on other sites More sharing options...
Members happwith12strin Posted May 28, 2013 Members Share Posted May 28, 2013 As an experiment, I hooked up two Pioneer consumer stereo speakers (non pa speakers) to a power amp.they played for 20 minutes and then caught fire. Link to comment Share on other sites More sharing options...
Members dboomer Posted May 28, 2013 Members Share Posted May 28, 2013 I can't say whether the cause was AC or DC but since Dc will take out a speaker almost instantly I'm guessing AC is more of a problem. I've seen it happen with speakers rated at very high power levels too. I remember testing very high power woofers where the magnet was over 300 degrees so I'm guessing the temp could be double down in the gap. Now if you freeze up the vc and coil there could be some very high temps reach the cone. As you can guess manufacturers react quickly when the get such reports as liability can always come into play. Link to comment Share on other sites More sharing options...
Members Tomm Williams Posted May 29, 2013 Members Share Posted May 29, 2013 Add captain of a cruise ship to that list Link to comment Share on other sites More sharing options...
Members RoadRanger Posted May 29, 2013 Members Share Posted May 29, 2013 vort wrote: I don't remember any more what the album was, but when I tell the story, I joke that it was Black Sabbath. That'll teach yah for playing it backwards . Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted May 29, 2013 Members Share Posted May 29, 2013 Mutha Goose wrote: In general you will find this happen after an amplifier failure/problem that causes DC across the voice coil. The exact amount will depend on a lot of factors. But essentially what happens is that there is excessive heating allowing for a build of volitle gasses... when the voice coil opens, there is a small spark. If all of the conditions are correct, this small spark will contain enough engery to ignite the gases... and again, if all of the conditions are correct, there will be enough gases to ignite the cone. I have never seen this occur with AC. IME the ignition path (spark-gases-cone) is broken due to the air-flow induced by the cone motion. There are test methods to determine the points at which this could occur (I tech'ed on the research for EIA-636). I wasn't thinking about over-powering the snot out of a speaker... LOL! I guess I was thinking about closed systems and what happens within the context of a properly designed system. Link to comment Share on other sites More sharing options...
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