Members Guitarist4life Posted October 14, 2007 Members Share Posted October 14, 2007 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. Link to comment Share on other sites More sharing options...
Members modulusman Posted October 14, 2007 Members Share Posted October 14, 2007 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? Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted October 14, 2007 Author Members Share Posted October 14, 2007 i had the volume all the way up!but amp is just 300watts..the cab can handle 1000W peak:confused: Link to comment Share on other sites More sharing options...
Members moody Posted October 14, 2007 Members Share Posted October 14, 2007 i had the volume all the way up!but amp is just 300watts..the cab can handle 1000W peak:confused: 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. Link to comment Share on other sites More sharing options...
Members WynnD Posted October 14, 2007 Members Share Posted October 14, 2007 1000 watts peak500 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. Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted October 14, 2007 Author Members Share Posted October 14, 2007 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 Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted October 14, 2007 Author Members Share Posted October 14, 2007 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 Link to comment Share on other sites More sharing options...
Members moody Posted October 14, 2007 Members Share Posted October 14, 2007 1000 watts peak500 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). Link to comment Share on other sites More sharing options...
Members flanc Posted October 14, 2007 Members Share Posted October 14, 2007 I'd say 300watts is about right for that cabinet. Link to comment Share on other sites More sharing options...
Members Gary in NJ Posted October 14, 2007 Members Share Posted October 14, 2007 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. Link to comment Share on other sites More sharing options...
Members dboomer Posted October 14, 2007 Members Share Posted October 14, 2007 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. Link to comment Share on other sites More sharing options...
Members abzurd Posted October 14, 2007 Members Share Posted October 14, 2007 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). Link to comment Share on other sites More sharing options...
Members twostone Posted October 14, 2007 Members Share Posted October 14, 2007 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 Link to comment Share on other sites More sharing options...
Members agedhorse Posted October 14, 2007 Members Share Posted October 14, 2007 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? Link to comment Share on other sites More sharing options...
Members dboomer Posted October 14, 2007 Members Share Posted October 14, 2007 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 Link to comment Share on other sites More sharing options...
Members agedhorse Posted October 14, 2007 Members Share Posted October 14, 2007 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 I think the clipped waveform's increased harmonics was causing the HF overload which was lighting the protection lamps. This is not the same issue with the low frequency section. Link to comment Share on other sites More sharing options...
Members dboomer Posted October 14, 2007 Members Share Posted October 14, 2007 I think the clipped waveform's increased harmonics was causing the HF overload which was lighting the protection lamps. This is not the same issue with the low frequency section. High frequency harmonics have very little power to them. They increase the power maybe a couple of percent. Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted October 15, 2007 Author Members Share Posted October 15, 2007 i burned the tweeter! I bridged the amp (600W total) and connected the cab.. it sounded really good for a while, then, all of the sudden, the tweeter died. I opened the cab, took out the tweeter and opened it up. The coils are all black and smell horrible. so I guess I burned it. now, if i replace the driver's diaphragm, will it make it work again or do i need to replace the whole driver?? BTW, I found a new diaphragm on ebay for $21dlls Link to comment Share on other sites More sharing options...
Members Guitarist4life Posted October 15, 2007 Author Members Share Posted October 15, 2007 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? I dont know why but the amp starts to clip when I connect an SM58.. Im talking about the input clipping... why is that? Link to comment Share on other sites More sharing options...
Members moody Posted October 15, 2007 Members Share Posted October 15, 2007 I dont know why but the amp starts to clip when I connect an SM58.. Im talking about the input clipping... why is that? SM58 plugged into what? at what settings? What sort of cable? Link to comment Share on other sites More sharing options...
Members abzurd Posted October 15, 2007 Members Share Posted October 15, 2007 Bridged the amp? sigh..... why would you do that? Link to comment Share on other sites More sharing options...
Members sharnrock Posted October 15, 2007 Members Share Posted October 15, 2007 Is this guy for real? Link to comment Share on other sites More sharing options...
Members lifeloverwg Posted October 15, 2007 Members Share Posted October 15, 2007 Is this guy for real? Link to comment Share on other sites More sharing options...
Members Al Poulin Posted October 15, 2007 Members Share Posted October 15, 2007 It's not one of those new speakers with stage lighting effects built-in is it? Because that would be cool! Yeah, those Peak power ratings are not only useless, they are also dangerous to those who don't understand what they mean... It's not really fair to blame the user, because the 1000 watt number IS THERE. Why would it be there if the speakers couldn't handle it? They wouldn't just put it there to sell the speaker would they? I like Yorkville's definition of their Program Power rating which is the ONLY one listed on their cabinets : ''It means DO NOT APPLY MORE THAN THIS MUCH POWER TO THIS SPEAKER''. Simple, clear and given the 2 year Even if you break it warranty, probably pretty accurate. Al Link to comment Share on other sites More sharing options...
Members moody Posted October 15, 2007 Members Share Posted October 15, 2007 This guy is probably feeling plenty bad about what he's done without anyone rubbing it in. As to replacing the diaphram... I think just replacing that should be fine if the coil gap is still nice and clean?? I think in the given situation, if he wants to go louder than he is then he needs both more powerful speakers and more powerful amps. More importantly he needs to read, question, research and study before he goes any further. I had my period of killing speakers and amps but that was years ago, a bit of knowledge goes a long way. We've all made mistakes, don't think he's an idiot for doing it. Link to comment Share on other sites More sharing options...
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