pyellman Posted February 14, 2015 Share Posted February 14, 2015 I have a ProMedia 2.1 system, about 5 years old. The other day, I noticed the right satellite speaker was buzzing/humming pretty bad, and when I got closer, I could smell burning. I unplugged the system of course. Today, I took apart the satellite, and also took the back panel off the subwoofer/amplifier. There was no visible damage of any kind to the subwoofer/amp, it actually seems to be in very good shape. So, with the cover off the satellite so I could see exactly where the smoke might be coming from, I plugged the system back in and powered it up. Smoke immediately began coming from the mid-bass on the the satellite; it seems to be the cardboard-like part of the cone that is burning. It seems like a genuine fire hazard. Other than that, the components of the satellite speaker also seem to be in fine shape, including the braided wire that attaches to the cone. I'd be interested in hearing any theories on what might be the cause of the failure of the satellite, and whether it would be risky to attach a different (purchased used on Ebay, for example) satellite speaker to the right channel. Thanks for any thoughts. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 14, 2015 Share Posted February 14, 2015 Welcome to the forum! I am bumping this. This is a very curious thing. It seems like in order for this to happen you would need to have way too much power going to a speaker. Is there enough current at normal levels to cause a fire in any speaker? This would be a good one for the MythBusters. Anybody have an idea for our new friend? Quote Link to comment Share on other sites More sharing options...
pyellman Posted February 15, 2015 Author Share Posted February 15, 2015 Replying to my own post to add some information. First of all, I know almost nothing about this stuff, I'd just like to rescue my ProMedia 2.1 system if possible, so please bear with me. On further analysis, it looks like the voice coil is pretty cooked (see attachment). It took me a while to recognize this as the voice coil, I expected something bigger from looking at pics on the internet. I guess the burning/smoke was the voice coil and adhesive. Looking around, there are some opinions on the implications of a burnt voice coil, such as at sound.westhost.com/articles/speaker-failure.html#s7. According to this, discolouration in the middle or all over the coil indicates that the coil was "driven with too much audio power for too long". I almost never turned these speakers up past about 1/3 of the way, even accounting for Windows volume control. In fact, at the time of the burnout, my daughter was listening through headphones attached to that speaker, there was no sound coming out at all. Other sources blame "pure overpower", or a power surge for a fried coil. I have read that this system has fuses protecting both channels, but I have been unable to locate such a fuse on my model. Inside my subwoofer/amp I only see one fuse labeled "Fuse 1", and it looks nothing like the kind of replaceable fuse that is shown for this system in other posts on this forum (mine is square/grey-black). Here's a nice video of a speaker/coil being driven to the point of flameout youtube.com/watch?v=KErbjC98yoM. I will note that my speaker would begin to smoke almost immediately when powered up through the subwoofer/amp, without any movement at all. I've got a used ProMedia 2.1 satellite speaker coming in the mail, and I plan to harvest the mid-bass and put it in my satellite (which is also the control pod). I would like to hear if anyone has suggestions on how to test the other components, either in the amp or the satellite, to determine if they might be the source of the problem. As I said, a visual inspection reveals nothing, in fact everthing else is quite pristine. I want to feel safe leaving this speaker plugged in to the amp! Quote Link to comment Share on other sites More sharing options...
The History Kid Posted February 15, 2015 Share Posted February 15, 2015 Promedia would play nice with even the Quintets honestly...they're similar speakers. I've tested that theory without any issue. So a simple replacement will do just fine, probably cheaper and easier to find too. Quote Link to comment Share on other sites More sharing options...
OO1 Posted February 15, 2015 Share Posted February 15, 2015 too small speakers - too much power - too little overall quality - time to buy a serious speaker and have fun - Quote Link to comment Share on other sites More sharing options...
hydro_pyro Posted February 16, 2015 Share Posted February 16, 2015 If it was smoking without loud music playing, then it was caused by a power amp failure. Specifically, "fusing", when an output transistor or FET burns up and turns full-on, dumping full DC supply directly to the speaker. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 16, 2015 Share Posted February 16, 2015 FETs do get hot and burn out. As I understand they usually burn out in the shorted position. Makes sense... You might want to watch this sale: http://www.ebay.com/itm/One-Amplifier-For-Klipsch-ProMedia-2-1-THX-Computer-Speakers-USED-WORKS-/171679026398?pt=LH_DefaultDomain_0&hash=item27f8de0cde Quote Link to comment Share on other sites More sharing options...
OO1 Posted February 16, 2015 Share Posted February 16, 2015 FETs do get hot and burn out. As I understand they usually burn out in the shorted position. Makes sense... You might want to watch this sale: http://www.ebay.com/itm/One-Ampl FETs do get hot and burn out. As I understand they usually burn out in the shorted position. Makes sense... You might want to watch this sale: http://www.ebay.com/itm/One-Amplifier-For-Klipsch-ProMedia-2-1-THX-Computer-Speakers-USED-WORKS-/171679026398?pt=LH_DefaultDomain_0&hash=item27f8de0cde super cheap solution ifier-For-Klipsch-ProMedia-2-1-THX-Computer-Speakers-USED-WORKS-/171679026398?pt=LH_DefaultDomain_0&hash=item27f8de0cde 1 Quote Link to comment Share on other sites More sharing options...
pyellman Posted February 16, 2015 Author Share Posted February 16, 2015 Thank you very much for the input. I have to think the thought about the fused transistor or FET is on the mark. Maybe I'll check the voltage on that output for grins. I guess I will be bidding on that used amp, but laughing at myself at the same time -- if I replace that, I'll have replaced everything but the the left satellite! Still be cheaper and better than the garbage Logitech system I just sent back. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 17, 2015 Share Posted February 17, 2015 Thank you very much for the input. I have to think the thought about the fused transistor or FET is on the mark. Maybe I'll check the voltage on that output for grins. I guess I will be bidding on that used amp, but laughing at myself at the same time -- if I replace that, I'll have replaced everything but the the left satellite! Still be cheaper and better than the garbage Logitech system I just sent back. Also, there was a guy on last week who said the new Klipsch 2.1's aren't nearly as good as the one you have. he bought one and returned it. Fixed up his old 2.1 and kept on truckin'. Quote Link to comment Share on other sites More sharing options...
DaveWJr Posted June 4, 2015 Share Posted June 4, 2015 Are you positive that the speaker wasn't making a very violent sound at some point? The cardboard piece you're talking about is called the former. There's a little 1-2mm extension below the last winding of voice coil (what your thumb is touching in the picture). Did you crush that area, or was it like that when you removed it? It should be perfectly cylindrical. My theory is that it bottomed out very severely (where the cone moves so far that the former slams into the bottom of the motor, therefore crushing that part I pointed out), and became misaligned. The next time you turned on the system, the voice coil was stuck at an angle, so even if you kept going up in volume, it's just going to make a buzzing/rubbing sound and not be able to cool itself. Bottoming out happens for a multitude of reasons, hence it's important to know if you heard anything at any time besides a buzz. Let me know. Quote Link to comment Share on other sites More sharing options...
DaveWJr Posted June 4, 2015 Share Posted June 4, 2015 And no, you can't cause a fire from a loudspeaker unless you actually try to. Even if ported, voice coils cook so quickly that you won't get enough oxygen into the box to catch something else on fire. More importantly, any voice coil big enough to be a fire threat wouldn't be on a former that's made of a flammable material. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted June 4, 2015 Share Posted June 4, 2015 And no, you can't cause a fire from a loudspeaker unless you actually try to. Even if ported, voice coils cook so quickly that you won't get enough oxygen into the box to catch something else on fire. More importantly, any voice coil big enough to be a fire threat wouldn't be on a former that's made of a flammable material. Dave, Thank you for clearing something up for me. I always thought the former was the slot/gap where the former rides. I did not know the former was the tube the voice coil wrapped around. Quote Link to comment Share on other sites More sharing options...
DaveWJr Posted June 4, 2015 Share Posted June 4, 2015 (edited) Nope! That gap-like area is given the technical name of: gap. Technically magnetic gap, but close enough. Edited June 4, 2015 by DaveWJr 2 Quote Link to comment Share on other sites More sharing options...
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