Blown Speaker

[dougnelson]

Sound on a BLI M1 stopped working. No response after resetting CV and using button reset, I contacted BLI and they sent me a new speaker.  Transplant was successful!  Any ideas why speakers blow?  And any tips to preventing this from happening again. Thanks.

[Steveruger45]

Speakers can “blow” for a number of reasons.
To mention a few,
1. Too much signal for too long.
2 Impedance too low for the amplifier.
3. Speaker Power capacity too low for the amplifier
4. Physical damage,  old age, brittle diaphragm.   And more.

I would assume BLI matched the speaker they fit with the decoders amplifier so 2 should not be the cause, plus this problem would more likely damage the amplifier.
It could be the speakers power capacity is right on or a little below the amps output power and then 1 came into play.   Turning down the volume could help in this case.

[wazzou]

Keep it below 10.

[dougnelson]

Speakers can “blow” for a number of reasons.
To mention a few,
1. Too much signal for too long.
2 Impedance too low for the amplifier.
3. Speaker Power capacity too low for the amplifier
4. Physical damage,  old age, brittle diaphragm.   And more.

I would assume BLI matched the speaker they fit with the decoders amplifier so 2 should not be the cause, plus this problem would more likely damage the amplifier.
It could be the speakers power capacity is right on or a little below the amps output power and then 1 came into play.   Turning down the volume could help in this case.

These seem to be mostly out of my control.  Any chance that dirty track or dust could play a role?

[Steveruger45]

These seem to be mostly out of my control.  Any chance that dirty track or dust could play a role?

Unlikely.

[peteski]

Since it is unlikely that too much power was applied, and the speaker's impedance was matched to the decoder (since it was selected by the manufacturer) it is unlikely that the defect was caused by something electrical (like too much current burning out the coil, or the leads that feed the coil).  Especially since the new speaker works when hooked up to the original decoder. It was likely a mechanical failure.  Have you measured the resistance between ther speaker's terminals?  Is it an open circuit?

My suspicion is that one of the feed wires between the solder terminals and the voice coil failed (broke, unsoldered?).  If you very carefully take the speaker apart, you might be able to do a postmortem.

[dougnelson]

Peteski:  I disconnected the speaker wires and reconnected them to the new speaker and it was back working.  Maybe a failure inside the speaker, but it does not sound like there is anything to be done to avoid this.

[jdcolombo]

I suspect your speaker was defective from the start - probably a bad wire in the voice coil that failed.  It happens.

As others have noted, speakers can fail as a result of over-driving by an amp and other things, none of which would appear to apply here.  Chalk it up to bad karma.  The replacement will likely work forever.

John C.

[dougnelson]

I suspect your speaker was defective from the start - probably a bad wire in the voice coil that failed.  It happens.

As others have noted, speakers can fail as a result of over-driving by an amp and other things, none of which would appear to apply here.  Chalk it up to bad karma.  The replacement will likely work forever.

John C.

Fingers crossed.  Thanks.

[peteski]

Peteski:  I disconnected the speaker wires and reconnected them to the new speaker and it was back working.  Maybe a failure inside the speaker, but it does not sound like there is anything to be done to avoid this.

You're rigth.
I just thought you were interested in figuring out what failed inside the speaker. When something fails I often like to play a detective to try to figure out what happened to cause the failure.