So i burnt my voice coil 3 weeks ago, and have been using the same speakers since. I havent gotten around measuring the ohm but the burnt woofer plays fine and theres no rubbing. But the thing is the burnt smell still lingers, after 3 weeks!
Could it be the motor is constantly overheating now or is the smell of enamel really that noxious?
Could it be the motor is constantly overheating now or is the smell of enamel really that noxious?
You did not *burn* your voicecoil or your speaker would not sound at all, at most you *overheated * it.
And yes, toasted Epoxy stinks.
If ,that is what happens when not all the turns have been roasted, some may be short circuited, others not, which makes the voice coil not have its original impedance value. Measuring the DC value can give us an idea of the damage if we can compare it with a similar healthy speaker.
One of the manufacturers of car audio speakers more known (and very good) in the 70´s were the Jensen.
At one point I bought a couple of coaxial speakers two ways from housed them in the front doors of my car.
They did not sound bad, but it was not the sound that I expected from the Jensen, that sounded very muted in the media and with poor bass, I thought I had not hit the best model.
When measuring them, the two measured very similar, below their nominal value as they should be, so do not imagine anything strange ...
Some years later, I sold that car and the buyer did not want to pay an extra minimum for the sound equipment improved by me, (including the FM-cassette player, also Jensen) so I took everything apart and stayed on a shelf.
The water had run out and damaged the paper cones, even though they were talking with a closed casing on their top to prevent this.
So I decided to restore them to make some small boxes to use them with a desktop PC. (At no little distance away, they are not armored)
When disarming them, I found the cause of the bad sound, they had been used (and very badly) and they had several toasted and short turns, from there their bad sound.
Buy new cones, enameled wire of the exact size, and await the dream of the righteous in a box.
I think what discourages me the most is that they are double-wound, doing the job on a paper former involves looking for a piece that is the exact size to avoid deformation, etc, etc ...
I reworked the frame so that they breathe well, so in the next post - in the thread car audio - will go the photos the porn photos for the voyeurs...
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This persistant smell is the driver's revenge for being abused !!!
I would also measure it to be sure it doesn't have any shorted windings. I guess there is a second one around for comparison.
Regards
Charles
I measured them and theyre about the same? The burnt one's 6ohm, the undamaged ones 6.1
I discard that I would have used a multimeter with a very low scale to measure ohms.
That said, there can not be a difference of only one tenth of ohms between an operating speaker (typically the impedance is measured 1000 hertz, it depends on the type of speaker and the manufacturer) and an unconnected one where only one resistance of a winding is measured. copper.
(The normal thing is that an 8-ohm speaker measures around 6 ohms or less in DC, a 4-ohm speaker can be around 2 ohms) but that depends a lot on the type of speaker (the design of your motor).
The burned sector adds the resistance that should not have in DC, hence that misleading reading.
Send it to repair, or burn your amplifier, as you have already indicated.
That will not eliminate the risk that the turns will short-circuit in a total overheating.
The enamel no longer fulfills its function of isolation between them .
Yeah, that burnt smell coats/adsorbs onto everything (cone, magnet, basket, enclosure) and continues out gassing seemingly forever.
You could remove the drivers and leave the box and drivers out in the sun for a couple of days after a wipe down with a moist cloth.
This will help but the source of the smell is the cooked voice coil and this will continue to 'stink' for quite a while.
Dan.
You could remove the drivers and leave the box and drivers out in the sun for a couple of days after a wipe down with a moist cloth.
This will help but the source of the smell is the cooked voice coil and this will continue to 'stink' for quite a while.
Dan.
^ That's assuming that the burnt part is in the overhung part of an overhung coil.
If it stinks badly then likely the insulation is already quite damaged. If a short happens between adjacent turns there will be negligible change to resistance or inductance. If a short happens between layers, both will drop drastically, make the coil heat up drastically more than normal and also potentially damage the amplifier.
I would replace the driver as it's probably a ticking time bomb.
If it stinks badly then likely the insulation is already quite damaged. If a short happens between adjacent turns there will be negligible change to resistance or inductance. If a short happens between layers, both will drop drastically, make the coil heat up drastically more than normal and also potentially damage the amplifier.
I would replace the driver as it's probably a ticking time bomb.
The variation of inductance will be very high.
I verified this on a tweeter with a shorted turn.
I can explain why. It is exactly like with the transformer when you check the leakage inductance with the secondary coil shorted.
The ability of the coil to storage e energy is much affected and this means less inductance, not because the coil has a turn less but because of a shorted turn that consume energy.
I verified this on a tweeter with a shorted turn.
I can explain why. It is exactly like with the transformer when you check the leakage inductance with the secondary coil shorted.
The ability of the coil to storage e energy is much affected and this means less inductance, not because the coil has a turn less but because of a shorted turn that consume energy.
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