I purchased a Fi 18BL dual 1 ohm. built a box for it and installed in a silverado. the silverado had two Massive Audio N4 amplifiers. The end goal was one on each coil and we started with that. did some testing, and it was stupid loud. resulted in my neighbor coming out to yell at me because we were shaking things off his walls during some initial testing.
For break-in we wired it up on one amp with coils in series for a 2 ohm load, 1kw per coil. End goal was 2kW RMS per coil (4kW Peak).
the sub lasted for 3 hours total (install to failure), maybe 60 minutes of actual use. all but a few seconds of it was on music at a reasonable volume. even the sine wave signals were well controlled. the output was 139.7dB on TL shortly before it failed, a few seconds at a time looking for frequency peak, not being pushed very hard. Gains set with a scope. good excursion but nothing extreme.
coil unwound from the former. that is what is wrong.
spent 2 weeks with Fi going back and forth, they asked all sorts of questions (typical stuff i would ask). finally gave me an RMA.
they reviewed the sub and said the suspension was still stiff and the sub looked new. no damage or issue other than the coil off the former. they said that because the sub was still stiff, i must have wired the coils out of phase. that is their way of getting out of a valid warranty claim.
i say the sub would not be possible of 140dB of output if the coils were out of phase. i know how to wire coils correctly. i say the sub looks and feels new because it only had an hour of use. of course it's stiff.
i measured the coils after the issue and one was 1 ohm and the other was 2 ohm. i didn't measure them before. neither coil was open, the glue just let loose. i know coil resistance can change when a sub has issues, but i suspect mismatched coils is what caused the issue in the first place. i see this as a clear instance of a mfr defect.
we are still negotiating.
other's have experience with this?
i have pics...