QuestionMy subs twice now have burnt to a crisp. The voils coils are so black that it looks like someone has spray painted them. First off, have you ever seen anything like this and if so, what caused it and what did you do to fix it? My subs and amp are MTX and the amp is the one that is rated for those subs. Everything has been installed by profetionals, so im not sure what the problem is and why its doing that?
If you have a fourms section on your site, or you have other people you can ask this questions to, i would love to hear as much feed back as possible as i would like nothing more then to have a working sterio in my car
AnswerPaul,
To answer both parts of your 1st question:
Yes, I certainly have seen this before.
The voice coils may have been treated with a black material from the factory but even of they do not appear burnt, I would bet the voice coil wires broke in 1/2 (put an ohmmeter across their leads to see for sure).
If they are 'open', it is time for new speakers as most professional reconing shops would laugh at you (possibly not to your face) for bringing them anything that was not a McCaulley, JBL, Bozak, Altec ect..
Why it happened:
The voice coil has more heat than it can dissipate due to its' design and the current that goes through it.
At least a few things can cause it but it boils down to overheating of the VC.
1) Incorect Impedance load on the amp.
2) Amp Levels set to high (the use of 45hz 'bass boost' buttons should be avoided at all times). The amp level adjustments should be done with all EQ settings 'flat', no treble or bass, loudness or DSP's boosts on.
3) Improper crossover settings.
4) Incorrect (or poorly constructed) enclosure for the speakers.
5) Defective amplifier.
How can it be fixed?
How can it be prevented is probably a more pertinent question in this case.
I have never had great luck with MTX speakers.
I remember using an 18 made by them for about 2 weeks [and I blew two of them in that time frame]. I blew the 2nd one in about 2 seconds (playing the same tune that had blown the 1st one).
Knowing that it had been setup very correctly, I decided real fast that just because a speaker has a 10 year warranty does not mean I want to replace one every week for the next ten years and I choose to get a pair of Kicker C-18's [which are bulletproof at specified loading and wattage levels].
*I might add that there is probably no speaker on earth that could not be damaged by misuse in the gain structure/crossover setup or by the operator.
I do not know if the install shop advised you to buy MTX or what (and it is very hard to know exactly what a customer will subject their system to once it is installed).. that said:
If you really want the subs to be bulletproof, do some research for advice (from me, for instance) then purchase better speakers.
On the lighter side:
I have seen some MTX amps that really pounded but I have never seen one that (driven hard) lasted very long either.
As to the 2nd question:
This would fall under the 'what caused it' section.
Sorry , but I do not know of a forum here at allexperts for non-volunteering members.
I hope this sheds some light on this speaker issue for you.
If you need more information or a second opinion, please feel free to re-ask this to another volunteer. We aim to please.
Sincerely,
Jerry Mael
