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Author Topic: JBL MP418 SP powered single 18 sub (built in ce2000)  (Read 5516 times)

Bill Burford

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JBL MP418 SP powered single 18 sub (built in ce2000)
« on: June 10, 2011, 05:40:01 am »

I purchased a JBL MP418SP powered sub in 2002.
the built in Crown CE2000 finally kicked the bucket.  It still works at low levels but clips very early.  My best description of where it would typically clip now is (on the internal amp channel.. external amp with load not clipping when internal clips) around -50 to -40dB.  The amp goes into thermal shutdown when cold after clipping a few times.

How the amp was used (misused):
I'd say it had been used for nearly 2000 hours at levels which would cause it to frequently clip intermittently when some component(s) finally gave out within the amp a few weeks ago.  the sub sounded the same as always (I think).

I am pleased with the sub.  I didn't think it would last that long the way I ran it.
More info: I estimate that for the first 600 hours of use or so that I ran the crossover open-ended sending it frequencies down to however low rock music goes ( not to mention unusually high compression on bass guitar for that period ).  After the first ~600 hours I eventually rolled off the x-over at 12 dB/octave BW at I believe 28Hz which I knew was useless but I was hoping my sub was special and would one day surpass the other MP418ís.  I have not tried to measure the impedance of the driver coil yet.  I roll off my newer subs at a higher frequency (to the tune of 6 Hz above the driver response) and steeper slope after considering many of the valuable comments/critiques in the old forums. I hope this was appropriate.
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Tim McCulloch

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Re: JBL MP418 SP powered single 18 sub (built in ce2000)
« Reply #1 on: June 11, 2011, 11:30:52 am »

Hi Bill-

I've followed your story regarding MP418 in another forum here.  I really think the issue is a bad output transistor or driver transistor, or possibly a defect in the protection circuit.

Other than the amp issue, what was your sonic impression of the MP418, and how does it compare to other subs you've used?

Tim "No dog in this fight" Mc
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Randall Hyde

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Re: JBL MP418 SP powered single 18 sub (built in ce2000)
« Reply #2 on: June 12, 2011, 12:16:32 pm »



Other than the amp issue, what was your sonic impression of the MP418, and how does it compare to other subs you've used?

Tim "No dog in this fight" Mc

I have a couple of the passive variant from my first sound system.
If you do the typical "one sub on each side of the stage" these guys are almost useless for live acts. They work well for recorded music, but suck at live work.

However, if you stick the pair of them together and couple them, they actually work, sort of. Won't kick your chest in at all, but you can *hear* some low frequency stuff from them.

They do make *great* speaker stands, though :). I often put them one per side for use as stands for a couple of JBL 225 columns in my "C" system. I leave one of them unplugged and the sound is better throughout the venue when doing that (well, except for power alley, of course).

I've long since bought a bunch of SRX 728s cabs (running off IT8000 amps), so I'm a bit spoiled. But I get lots of small jobs that won't pay for the SRX rig, so the Mpro 418 cabs let me provide "subs" for those jobs. One big advantage of the 418s cabs is that one person can setup and run the whole show. Can't do that with the SRX 728s :(
Cheers,
Randy Hyde
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