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  • JBL JRX115 crossover GLOW!!!!

    I just bought a brand new JBL Jrx115 (250w-1000w 8ohm) cab

    I was trying it with Soundtech 300w(8ohm) amp and to my surprise, the crossover inside the JBL cab started glowing! it looked like it was about to go on fire.
    I know it doesn't suppose to do that because when I lowered the volume, the glowing stopped.
    Im new to this PA thing. Help. What could be causing the glow?
    any opinions are welcomed.
    Im a perfectionist who isn't perfect.

  • #2
    It is probably a light bulb inside the cab that is suppose to soak up the excess power to keep you from frying your horn driver. How loud were you?

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    • #3
      i had the volume all the way up!
      but amp is just 300watts..
      the cab can handle 1000W peak
      Im a perfectionist who isn't perfect.

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      • #4
        i had the volume all the way up!
        but amp is just 300watts..
        the cab can handle 1000W peak


        What is that in RMS?? The amp is probably clipping at way more than 300watts. Be glad you're seeing lights instead of hearing nothing.

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        • #5
          1000 watts peak
          500 watts continuous (Might be RMS rating)
          300 watt amp pushed for everything it's worth might be sending some level of distorted sound out at 600 watts. I'm with the other guys. Be glad it's still working and back it off some in the future. Replacing or reconing drivers ain't no fun. Maybe shedding several hundred dollars every month might make you rethink the "louder must be better" approach to music.

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          • #6
            I was told that JBL recommends a 250w-500w amp..
            mine is 300w, so I thought it wasn't that bad.

            Its not that i want to use it at extremely loud levels.. Its just not loud enough to mic the drum kit, bass, vocals, guitars and keyboard. We would probably sound louder using our individual amps LOL!
            BTW, my amp/mixer is 300wx2 @8ohms

            I just cant understand why the crossover light bulbs are glowing with 300w when it suppose to handle up to 1000W
            Im a perfectionist who isn't perfect.

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            • #7
              It is probably a light bulb inside the cab that is suppose to soak up the excess power to keep you from frying your horn driver. How loud were you?


              you're right!
              I checked the crossover and saw two small light bulbs in there!
              thanks
              Im a perfectionist who isn't perfect.

              Comment


              • #8
                1000 watts peak
                500 watts continuous (Might be RMS rating)
                300 watt amp pushed for everything it's worth might be sending some level of distorted sound out at 600 watts.


                It might be pushing out even more than that.

                Alternatively, because the bulbs are protecting the high end of your system, the high frequency section of the speaker will not take as much as the low end?? have you got a lot of high end signal going through?? (I'm not sure how it works and I've rarely had problems with to much high).

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                • #9
                  I'd say 300watts is about right for that cabinet.
                  https://www.facebook.com/pages/Full-Steam/179028619290

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                  • #10
                    I was told that JBL recommends a 250w-500w amp..
                    mine is 300w, so I thought it wasn't that bad.


                    All amps distort when pushed to their maximum output, some more then others. What is important is that the speakers see "clean" power. If you want to drive the speakers in that 300 watt region, do it with an amp that can put out 500 to 600 watts. This way you are assured that clean power is reaching the speakers.
                    Gary

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                    • #11
                      One thing that people forget about speaker ratings. Manufacturers do publish power ratings ... but none of them believe the speakers sound good at those levels. Distortion goes up dramatically as the power rises.

                      Besides this ... the distortion really goes up when you light up the protection circuit.
                      Don Boomer

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                      • #12
                        Keep in mind too that "all the way up" really doesn't mean much. The volume knobs on the amps are just input sensitivity (basically a mixer). For instance, if you backed down the knobs to 2/3, that doesn't mean you're only giving the speakers 200w. If you hit the amp with a hot signal you can still get it to put out max power and then some (the "and then some" would be the clipping). If your amp doesn't have clip limiters you may want to invest in an outboard limiter, especially if running sound yourself (nobody watching it all the time).
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                        • #13
                          Keep in mind too that "all the way up" really doesn't mean much. The volume knobs on the amps are just input sensitivity (basically a mixer). For instance, if you backed down the knobs to 2/3, that doesn't mean you're only giving the speakers 200w. If you hit the amp with a hot signal you can still get it to put out max power and then some (the "and then some" would be the clipping). If your amp doesn't have clip limiters you may want to invest in an outboard limiter, especially if running sound yourself (nobody watching it all the time).


                          Maybe a clip limiter recommendation might help

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                          • #14
                            Don, THIS is why I make many of the recommendations the way I do... this is what the majority of the market you were selling into consists of.

                            Guitarist4life, your speakers are 250 watts RMS, the 300 watt amp is a great match for the way you are likely to operate your gear. Now, if 300 watts (undistorted) does not deliver enough volume for your application, you need more speakers and more power. Or, much more efficient speakers is another possibility.

                            When you drive the snot out of an amp (were the red clip lights flashing on the amp... do you understand what this means?) the resulting distortion increases the high frequency content of the program and overloads the high frequency drivers in the speakers. The lamps absorb this high frequency overload and protect the drivers... but this is not foolproof and if you keep doing this there WILL be damage.

                            Out of curiosity, what makes you think you can turn everything up all the way? Disn't the awful distorted sound cause you any concern... did you notice this?
                            -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                            Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

                            Currently product development engineer: Mesa Boogie

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                            • #15
                              Maybe a clip limiter recommendation might help


                              Clip limiting is not what you need ... average/continuous/rms limiting is what is called for. Clipped peaks are tolerable to the listener. The other thing is peaks are usually not the problem with speaker burnout
                              Don Boomer

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